Document:

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                                                                 EXHIBIT 10.5

                          LOAN AND SECURITY AGREEMENT

Agreement No. ________

                         Dated as of January 30, 1998

                                    between

                           MMC/GATX PARTNERSHIP NO. I
                            Four Embarcadero Center
                                   Suite 2200
                            San Francisco, CA 94111

                                   as Lender

                                      and

                                VIROLOGIC, INC.
                             a Delaware corporation
                              270 E. Grand Avenue
                         South San Francisco, CA 94080

                                  as Borrower

                           CREDIT AMOUNT: $3,000,000

Repayment Period:                       48 months
Treasury Note Maturity:                 48 months
Minimum Funding Amount:                 $100,000
Loan Margin:                            450 basis points
Maximum Number of Fundings:             Ten (10)

                 Commitment Termination Date: December 31, 1998

     The defined terms and information set forth on this cover page are a part
of the Loan and Security Agreement, dated as of the date first written above
(this "Agreement"), entered into by and between MMC/GATX PARTNERSHIP NO. I
("Lender") and the borrower ("Borrower") set forth above. The terms and
conditions of this Agreement agreed to between Lender and Borrower are as
follows:

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     1.01. Certain Definitions. Unless otherwise indicated in this Agreement or
any other Operative Document, the following terms, when used in this Agreement
or any other Operative Document, shall have the following respective meanings:

     "Borrower's Home State" shall mean the state in which Borrower's principal
place of business is located.

     "Business Day" shall mean any day other than a Saturday, Sunday or public
holiday under the laws of California, or other day on which banking
institutions are authorized or obligated to close in California.

     "Claim" has the meaning given to that term in Section 10.03.

     "Collateral" has the meaning given to that term in Section 5.01(a).

     "Commitment Fee" shall mean the fee previously paid by Borrower to Lender
upon the execution and delivery by Lender and Borrower of the "term sheet"
setting out certain principal terms and conditions of the transaction
contemplated by this Agreement.

     "Commitment Termination Date" shall mean the date specified on the cover
page of this Agreement.

     "Credit Amount" shall mean the maximum amount that Lender is committed to
lend (if the conditions specified in Schedule 3 are satisfied), which amount is
set forth following such term on the cover page of this Agreement.

     "Default" shall mean any event which with the passing of time or the
giving of notice or both would become an Event of Default hereunder.

     "Default Rate" shall mean the per annum rate of interest equal to the
higher of (i) 18% or (ii) the Prime Rate plus 6%, but such rate shall in no
event be more than the highest rate permitted by applicable law.

     "Eligible Equipment" shall mean scientific laboratory, test equipment and
automated processing equipment, reasonably acceptable to Lender.

     "Environmental Law" shall mean the Resource Conservation and Recovery Act
of 1987, the Comprehensive Environmental Response, Compensation and Liability
Act, and any other federal, state or local statute, law, ordinance, code, rule,
regulation, order or decree (in each case having the force of law) regulating
or imposing liability or standards of conduct concerning any Hazardous
Material, as now or at any time hereafter in effect.

     "Equipment" has the meaning given to that term in Section 5.01(a).

     "Event of Default" has the meaning given to that term in Section 9.01.

     "Event of Loss" has the meaning given to that term in Section 6.01(e).

     "Final Payment" shall mean, with respect to each Loan, a payment (in
addition to the regular monthly payment of principal and accrued interest on
the Note) due on the Maturity Date for such Loan in an amount equal to the Loan
Amount for such Loan multiplied times ten percent (10.0%).

     "Funding Date" shall mean any date on which a Loan is made to or on
account of Borrower under this Agreement.

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     "Hazardous Material" means any hazardous, dangerous or toxic constituent
material, pollutant, waste or other substance, whether solid, liquid or
gaseous, which is regulated by any federal, state or local governmental
authority.

     "Intellectual Property" shall mean Borrower's interest in any patent
applications, trademarks, copyrights, computer programs, design rights,
license rights, trade secret rights, rights to unpatented inventions,
know-how, operating manuals, claims for damages by way of any past, present
and future infringement of any of the foregoing, and all proceeds thereof.

     "Interim Payment" shall mean, with respect to each Loan, an amount equal
to the initial Loan Amount multiplied by the percentage equal to the product of
(i) the quotient derived from dividing the initial Loan Factor with respect to
such Loan by 30, and (ii) the number of days from (and including) the Funding
Date of such Loan to (but not including) the first Payment Date with respect to
such loan.

     "Landlord Consent" shall mean a consent in the form of Exhibit B or such
other form as Lender may agree to accept.

     "Lien" shall mean any pledge, bailment, lease, mortgage, hypothecation,
conditional sales and title retention agreements, charge, claim, encumbrance or
other lien in favor of any Person.

     "Loan" shall mean each advance by Lender to Borrower under this Agreement.

     "Loan Amount" shall mean, as of any date, with respect to each Loan, the
original principal amount of such Loan less the aggregate of all Stated Costs
of Equipment with respect to which prepayments of such Loan have been made.

     "Loan Factor" shall mean, with respect to each Loan, the amount set forth
as a percentage with respect to such Loan in the applicable Loan Terms
Schedule, calculated using the Loan Rate applicable to such Loan.

     "Loan Margin" shall mean the number of basis points set forth following
such term on the cover page of this Agreement.

     "Loan Rate" shall mean, with respect to each Loan, the per annum rate of
interest (based on a year of twelve (12) 30-day months) equal to the sum of (a)
the U.S. Treasury note rate of a term equal to the Treasury Note Maturity as
quoted in the Wall Street Journal on the date the Loan Terms Schedule for such
Loan is prepared, plus (b) the applicable Loan Margin.

     "Loan Terms Schedule" shall mean, with respect to each Loan, a schedule in
the form of Schedule 1 hereto, duly completed to set forth the terms applicable
to such Loan.

     "Loan Value" shall mean, with respect to each Loan, the percentage set
forth in the Loan Terms Schedule applicable to such Loan, determined as of the
Payment Date on which payment of an amount is to be made, or if such date is
not a Payment Date, as of the next Payment Date following such date.

     "Make-Whole Premium" means an amount equal to the greater of (i) zero and
(ii) the excess of (x) the sum of the present values, at the date of prepayment
of (1) the amount of all accrued and unpaid Scheduled Payments with respect to
the Loans or portion of such Scheduled Payments, which will not be required to
be made as a result of such prepayment, and (2) the Final Payment with respect
to the Loans (each such payment an "Amount Payable") (each such Amount Payable
discounted separately at the Treasury Rate, determined on the date three (3)
Business Days before the date of prepayment, compounded monthly, from the date
such Amount Payable would be due), over (y) the aggregate principal amount of
the Loans to be prepaid. The "Treasury Rate" shall be the yield (as quoted in
the Western edition of The Wall Street Journal on the date which is three (3)
Business Days prior to the date

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of prepayment) on U.S. Treasury securities adjusted to a constant maturity
equal to the then remaining number of full months to maturity of the Loans.

     "Maturity Date" shall mean, with respect to each Loan, the last Business
Day of the Repayment Period applicable to such Loan.

     "Maximum Number of Fundings" shall mean the maximum number of fundings
under this Agreement specified on the cover page of this Agreement.

     "Minimum Funding Amount" shall mean the dollar amount specified on the
cover page of this Agreement.

     "New Equipment" shall have the meaning given to that term in the
applicable Loan Terms Schedule if such term is used in connection with this
Agreement.

     "Note" shall mean the promissory note of Borrower, substantially in the
form of Exhibit A.

     "Obligations" has the meaning given to that term in Section 5.01.

     "Officer's Certificate" has the meaning given to that term in Schedule 3.

     "Operative Documents" shall mean this Agreement, the Note, the Warrant,
the Landlord Waiver and Consent(s) and all other documents, instruments and
agreements (including Loan Terms Schedules) executed and delivered in
connection herewith or therewith or in respect of the closing of the
transactions contemplated hereby or thereby.

     "Payment Date" has the meaning given to that term in Section 2.04(a).

     "Permitted Liens" shall mean (a) the Lien created by this Agreement,
(b) Liens for fees, taxes, levies, imposts, duties or other governmental
charges of any kind which are not yet delinquent or which are being contested
in good faith by appropriate proceedings which suspend the collection thereof
(provided, however, that such proceedings do not involve any substantial danger
of the sale, forfeiture or loss of any item of Equipment and that Borrower has
adequately bonded such Lien or reserves sufficient to discharge such Lien have
been provided on the books of Borrower), (c) Liens identified on Schedule 2,
(d) Liens to secure payment of worker's compensation, employment insurance, old
age pensions or other social security obligations of Borrower in the ordinary
course of business of Borrower, and (e) minor easements, licenses,
reservations, covenants, conditions, waivers, on real property, restrictions on
the use of real property, or minor irregularities of title to real property,
which, in each case, do not in the aggregate materially impair the use thereof
in the operation of the business of Borrower.

     "Person" shall mean and include an individual, a partnership, a
corporation, a business trust, a joint stock company, a limited liability
company, an unincorporated association or other entity and any domestic or
foreign national, state or local government, any political subdivision thereof,
and any department, agency, authority or bureau of any of the foregoing.

     "Prime Rate" shall mean the interest rate per annum publicly announced
from time to time by Bank of America NT & SA (or its successor) as its
reference rate, but such rate shall in no event be more than the highest
interest rate permitted by applicable law.

     "Repayment Period" shall mean the period beginning on the first Payment
Date and continuing for the number of calendar months or quarters set forth
following such term on the cover page of this Agreement.

     "Scheduled Payments" has the meaning given to that term in Section 2.04(a).

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     "Stated Cost" shall mean, with respect to each item of Equipment, the
dollar amount assigned thereto, as set forth on Annex A to the applicable Loan
Terms Schedule, by Borrower and Lender at the time of the making of the Loan
for which such item of Equipment serves as collateral.

     "Subsidiary" shall mean any corporation of which a majority of the
outstanding capital stock entitled to vote for the election of directors
(otherwise than as the result of a default) is owned by Borrower directly or
indirectly through Subsidiaries.

     "Term" shall mean the period from and after the date hereof until the
payment or satisfaction in full of all Obligations under this Agreement and the
other Operative Documents.

     "Treasury Note Maturity" shall mean the period of months set forth
following such term on the cover page of this Agreement.

     "Warrant" shall mean a warrant to purchase securities of Borrower
substantially in the form of Exhibit C.

     1.02. Headings. Headings in this Agreement and each of the other Operative
Documents are for convenience of reference only and are not part of the
substance hereof or thereof.

     1.03. Plural Terms. All terms defined in this Agreement or any other
Operative Document in the singular form shall have comparable meanings when
used in the plural form and vice versa.

     1.04. Construction. This Agreement is the result of negotiations among,
and has been reviewed by, Borrower and Lender and their respective counsel.
Accordingly, this Agreement shall be deemed to be the product of all parties
hereto, and no ambiguity shall be construed in favor of or against Borrower or
Lender.

     1.05. Entire Agreement. This Agreement, together with the terms set forth
in each Loan Terms Schedule and each of the other Operative Documents, taken
together, constitute and, contain the entire agreement of Borrower and Lender
and, with regard to their respective subject matters, supersede any and all
prior agreements, term sheets, negotiations, correspondence, understandings and
communications among the parties, whether written or oral, with respect to
their respective subject matters.

     1.06. Other Interpretive Provisions. References in this Agreement to
"Articles," "Sections," "Exhibits," "Schedules" and "Annexes" are to recitals,
articles, sections, exhibits, schedules and annexes herein and hereto unless
otherwise indicated. References in this Agreement and each of the other
Operative Documents to any document, instrument or agreement shall include (a)
all exhibits, schedules, annexes and other attachments thereto, (b) all
documents, instruments or agreements issued or executed in replacement thereof,
and (c) such document, instrument or agreement, or replacement or predecessor
thereto, as amended, modified and supplemented from time to time and in effect
at any given time. The words "hereof," "herein" and "hereunder" and words of
similar import when used in this Agreement or any other Operative Document
shall refer to this Agreement or such other Operative Document, as the case
may be, as a whole and not to any particular provision of this Agreement or
such other Operative Document, as the case may be. The words "include" and
"including" and words of similar import when used in this Agreement or any
other Operative Document shall not be construed to be limiting or exclusive.
Unless otherwise indicated in this Agreement or any other Operative Document,
all accounting terms used in this Agreement or any other Operative Document
shall be construed, and all accounting and financial computations hereunder or
thereunder shall be computed, in accordance with generally accepted accounting
principles as in effect in the United States of America from time to time. The
terms and conditions set forth in each Loan Terms Schedule are incorporated
herein by this reference.

     2.01. Credit Facility. On the terms and subject to the conditions hereof
and relying upon the representations and warranties herein set forth as and
when made or deemed to be made, Lender agrees to lend to Borrower, from time to
time prior to the Commitment Termination Date, the Loans; provided,

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however, that the aggregate original principal amount of the Loans shall not
exceed the Credit Amount at any time; provided, further, that the aggregate
original principal amount of any Loan shall not exceed the aggregate original
cost of the items of Equipment being financed with such Loan; provided,
further, that the aggregate principal amount of the Loans relating to the
financing of transferable software licenses, freight, installation, software,
leasehold improvements and intangible items shall not exceed forty percent
(40%) of the Credit Amount. If repaid or prepaid, the principal of the Loans
may not be re-borrowed.

     2.02. Use of Proceeds; the Loans and the Note.

           (a) Use of Proceeds. The proceeds of the Loans shall be used solely
for the purchase of, or reimbursement to Borrower of the Stated Cost of,
Equipment.

           (b) The Loans and the Note. The obligation of Borrower to repay the
aggregate unpaid principal amount of and interest on and to make the Final
Payments on the Loans, or to pay the Loan Value of the Loan Amount applicable
to each Loan, shall be evidenced by the Note. Lender may, and is hereby
authorized by Borrower to, endorse on a grid annexed to the Note appropriate
notations regarding the Loans evidenced by the Note; provided, however, that
the failure to make, or an error in making, any such notation shall not limit
or otherwise affect the obligations of Borrower hereunder or under the Note.

     2.03 Procedure for Making Loans.

          (a) Loan Terms Schedule. Whenever Borrower desires that Lender make a
Loan, Borrower shall deliver to Lender a list of the Equipment proposed to be
financed by such Loan and request that Lender prepare a Loan Terms Schedule for
such Loan. Lender's obligation to make the initial Loan shall be subject to the
satisfaction of the conditions set forth in Sections 8.01 and 8.02. Lender's
obligation to make each subsequent Loan shall be subject to the satisfaction of
the conditions set forth in Section 8.02.

          (b) Loan Interest Rate. Borrower shall pay interest on the unpaid
principal amount of each Loan from the first Payment Date for such Loan until
such Loan is paid in full, at a per annum rate of interest equal to the Loan
Rate determined by Lender as of the Funding Date for such Loan in accordance
with the definition of Loan Rate. The Loan Rate applicable to each Loan shall
not be subject to change in the absence of manifest error. All computations of
interest on Loans shall be based on a year of twelve (12) 30-day months. If
Borrower pays interest on any Loan which is determined to be in excess of the
then legal maximum rate, then that portion of each interest payment representing
an amount in excess of the then legal maximum rate shall be deemed a payment of
principal and applied against the principal of the applicable Loan.

          (c) Loan Factor and Loan Value Calculation. Each Loan Terms Schedule
shall establish the Loan Factor and Loan Values with respect to such Loan. The
Loan Factor shall be calculated in a manner to fully amortize the Loan over the
Repayment Period applicable to such Loan in equal periodic installments. The
Loan Factor and Loan Values applicable to each Loan shall be conclusive in the
absence of manifest error.

          (d) Disbursement. Subject to the receipt by Lender of a Loan Terms
Schedule duly executed by Borrower and the satisfaction of the conditions set
forth in Sections 8.01 and 8.02 with respect to the initial Loan and the
satisfaction of the conditions set forth in Section 8.02 with respect to each
subsequent Loan. Lender shall disburse such Loan by wire transfer to Borrower
unless otherwise directed in writing by Borrower.

          (e) Termination of Commitment to Lend. Notwithstanding anything to
the contrary in the Operative Documents, Lender's obligation to lend the
undisbursed portion of the Credit Amount to Borrower hereunder shall terminate
on the earlier of (i) the occurrence of any Event of Default hereunder, and
(ii) the Commitment Termination Date.

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     2.04. Other Payment Terms.

          (a) Principal and Interest Payments On Payment Dates. Borrower shall
make payments of principal and accrued interest for each Loan (collectively,
"Scheduled Payments"), commencing on the date set forth on the Loan Terms
Schedule applicable to such Loan and continuing thereafter during the Repayment
Period on the first Business Day of each calendar month (each a "Payment
Date"), in an amount equal to the Loan Factor multiplied by the Loan Amount for
such Loan as of such Payment Date. The Loans may not be prepaid except in the
circumstances set forth in Section 6.01(e).

          (b) Interim Payment. Unless the Funding Date for a Loan is the last
Business Day of a month or a Payment Date, Borrower shall pay to Lender the
Interim Payment payable with respect to such Loan on the date specified in the
Loan Terms Schedule applicable to such Loan.

          (c) Final Payment. Unless a Loan is prepaid in full, on the Maturity
Date with respect to such Loan, Borrower shall pay, in addition to any
remaining unpaid principal and accrued interest and all other amounts
previously due with respect to such Loan, an amount equal to the Final Payment
with respect to such Loan.

          (d) Commitment Fee. The Commitment Fee is the fee equal to $10,000
previously paid to Lender by Borrower in consideration of Lender's written
proposal to Borrower dated October 8, 1997, which fee is to be applied as set
forth in the Loan Terms Schedule for each Loan.

          (e) Place and Manner. Borrower shall make all payments due to Lender
in lawful money of the United States at the address for payments and in the
manner specified in Section 10.05(b).

          (f) Date. Whenever any payment due hereunder shall fall due on a day
other than a Business Day, such payment shall be made on the next succeeding
Business Day, and such extension of time shall be included in the computation
of interest or fees, as the case may be.

          (g) Default Rate. If either (i) any amounts required to be paid by
Borrower under this Agreement or the other Operative Documents (including
principal or interest payable on any Loan, any fees or other amounts) remain
unpaid after such amounts are due, or (ii) an Event of Default has occurred and
is continuing, Borrower shall pay interest on the aggregate, outstanding
principal balance hereunder from the date due or from the date of the Event of
Default, as applicable, until such past due amounts are paid in full or until
all Events of Defaults are cured, as applicable, at a per annum rate equal to
the Default Rate, such rate to change from time to time as the Prime Rate shall
change. All computations of such interest shall be based on a year of twelve
(12) 30-day months.

     3.01. Representations and Warranties. Except as set forth on Annex C to
Schedule No. 1 hereto, Borrower makes the following representations and
warranties to Lender as of the date hereof and again on each Funding Date:

          (a) Organization and Qualification. Borrower is a corporation duly
organized, validly existing and in good standing under the laws of its state of
incorporation and is duly qualified to do business in the state(s) in which the
Equipment will be located.

          (b) Authority. Borrower has all necessary corporate power, authority
and legal right and has obtained all approvals and consents and has given all
notices necessary to execute and deliver this Agreement and the other Operative
Documents and to perform the terms hereof and thereof. Borrower has all
requisite corporate power and authority to own or lease and operate its
properties and to carry on its businesses as now conducted.

          (c) Conflict with Other Instruments, etc. Neither the execution and
delivery of any Operative Document to which Borrower is a party nor the
consummation of the transactions therein contemplated nor compliance with the
terms, conditions and provisions thereof will conflict with or result in a
breach of

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any of the terms, conditions or provisions of the charter or the bylaws of
Borrower or, to its knowledge, any law or any regulation, order, writ,
injunction or decree of any court or governmental instrumentality or any
material agreement or instrument to which Borrower is a party or by which it or
any of its properties is bound or to which it or any of its properties is
subject, or constitute a default thereunder or result in the creation or
imposition of any Lien, other than Permitted Liens.

          (d) Title to Properties. Borrower has good and marketable title to all
Equipment which constitutes or will constitute Collateral, free and clear of all
Liens, other than Permitted Liens.

          (e) Authorization, Governmental Approvals, etc. The execution and
delivery by Borrower of each Operative Document, the granting of the security
interest in the Collateral, the issuance of the Warrant, the issuance of the
securities into which the Warrant is exercisable, the issuance of any securities
into which the securities issuable upon exercise of the Warrant are convertible,
and the performance of the obligations herein and therein contemplated have each
been duly authorized by all necessary action on the part of Borrower. No
authorization, consent, approval, license or exemption of, and no registration,
qualification, designation, declaration or filing with, or notice to, any Person
is, was or will be necessary to (i) the valid execution and delivery of any
Operative Document to which Borrower is a party, (ii) the performance of
Borrower's obligations under any Operative Document, or (iii) the granting of
the security interest in the Collateral, except for filings in connection with
the issuance of the Warrant. The Operative Documents have been or will be duly
executed and delivered and constitute or will constitute legal, valid and
binding obligations of Borrower, enforceable in accordance with their respective
terms, except as the enforceability thereof may be limited by bankruptcy,
insolvency or other similar laws of general application relating to or affecting
the enforcement of creditors' rights or by general principles of equity.

          (f) Litigation. There are no actions, suits, proceedings or
investigations pending or, to the knowledge of Borrower, threatened against or
affecting Borrower, or the business or any property or asset owned by it, before
any court or governmental department, agency or instrumentality which if
adversely determined might have a material adverse effect on the financial
condition, business or operations of Borrower.

          (g) Disclosure. Neither any Operative Document nor any other
agreement, document or certificate furnished by Borrower to Lender, including,
without limitation, historical financial statements, contains any untrue
statement of a material fact or omits to state a material fact necessary in
order to make the statements contained herein and therein not misleading in
light of the circumstances in which they were made. There is no fact known to
Borrower which materially adversely affects, or which could in the future
materially adversely affect, its ability to perform its obligations under the
Operative Documents to which it is a party.

          (h) Security Interest. Assuming the proper filing of one or more
financing statement(s) identifying the Collateral with the proper state and/or
local authorities, the security interests in the Collateral granted to Lender
pursuant to this Agreement (i) constitute and will continue to constitute first
priority security interests (except to the extent any other Permitted Lien
(other than Permitted Liens identified in clause (e) of the definition thereof)
existing on the date of this Agreement may create any priority to Lender's Lien
under this Agreement) and (ii) are and will continue to be superior and prior
to the rights of all other creditors of Borrower (except to the extent of such
Permitted Liens).

          (i) Executive Officers. The principal place of business and chief
executive office of Borrower, and the office where Borrower will keep all
records and files regarding the Collateral, is set forth in Section 10.05(a).

     4.01. Furnishing Reports. Borrower shall furnish to Lender:

          (a) Financial Statements. So long as Borrower is not subject to the
reporting requirements of Sections 12 or 15 of the Securities and Exchange Act,
as amended, promptly as they are available, unaudited monthly and audited annual
financial statements of Borrower. From and after such time as

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Borrower becomes a publicly reporting company, promptly as they are available
and in any event: (i) within 10 days from the time of filing of Borrower's
Form 10-K with the Securities and Exchange Commission after the end of each
fiscal year of Borrower, the financial statements of Borrower filed with such
Form 10-K; and (ii) within 10 days from the time of filing of Borrower's
Form 10-Q with the Securities and Exchange Commission after the end of each of
the first three fiscal quarters of Borrower, the financial statements of
Borrower filed with such Form 10-Q.

          (b) Notice of Event of Loss. As soon as possible, and in any event
within fifteen (15) days thereafter, notice in writing in reasonable detail of
any Event of Loss.

          (c) Notice of Defaults. As soon as possible, and in any event within
five (5) Business Days after the discovery of a Default of Event of Default
provide Lender with an Officer's Certificate of Borrower setting forth the
facts relating to or giving rise to such Default or Event of Default and the
action which Borrower proposes to take with respect thereto.

          (d) Miscellaneous. Such other information as Lender may reasonably
request from time to time in connection with a Funding Date or otherwise.

     5.01. Grant of Security Interest.

          (a) Grant. Borrower, in order to secure the payment of the principal,
interest and Final Payment due with respect to the Loans made pursuant to this
Agreement, all other sums due under and in respect hereof and of the other
Operative Documents, including fees, charges, expenses and attorneys' fees and
costs and the performance and observance by Borrower of all other terms,
conditions, covenants and agreements herein and in the other Operative
Documents (all such amounts and obligations being herein sometimes called the
"Obligations"), does hereby grant to Lender and its successors and assigns, a
security interest in and to the following property (collectively, the
"Collateral"):

          All right, title, interest, claims and demands of Borrower in and to
     each and every item of equipment, fixtures, personal property,
     certificates of deposit or treasury notes, which is financed with a Loan
     on and after the date of this Agreement by designating such equipment,
     fixtures, personal property, certificates of deposit or treasury notes on
     Annex A to each Loan Terms Schedule, whether now owned or hereafter
     acquired, together with all substitutions, renewals or replacements of and
     additions, improvements, accessions, replacement parts and accumulations
     to any and all of such equipment, fixtures or personal property
     (collectively, the "Equipment"), together with all proceeds thereof,
     including, without limitation, insurance, condemnation, requisition or
     similar payments, and all proceeds from sales, renewals, releases or other
     dispositions thereof.

The security interest herein granted shall constitute a first priority security
interest upon the proper filing of one or more financing statements identifying
the Collateral with the proper state and/or local authorities.

          (b) After-Acquired Property. All Equipment which is financed through
Loans shall ipso facto, and without any further conveyance, assignment or act
on the part of Borrower or Lender, become and be subject to the security
interest herein granted as fully and completely as though specifically
described herein. The definition of the term "Equipment" shall be deemed
amended on each Funding Date to incorporate all property financed with, or
which will constitute Collateral for, the Loan advanced on such Funding Date.
Any failure to formally amend such definition shall not affect the grant by
Borrower to Lender of the security interest in such Collateral pursuant to this
Article V. This Agreement and the other documents in connection herewith may be
supplemented and amended from time to time, as required by Lender, to reflect
the additional Collateral subject to the security interest granted pursuant to
this Article V.

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     5.02. Duration of Security Interest. Lender's security interest in the
Collateral shall continue until the payment in full and the satisfaction of all
Obligations, whereupon such security interest shall terminate; provided,
however, that if any item of Collateral is subject to an Event of Loss, then
following the prepayment of the Loan with respect to such item pursuant to
Section 6.01(e), Lender shall release its security interest in such item of
Collateral. Lender shall execute such further documents and take such further
actions as may be necessary to effect the release and/or termination
contemplated by this Section 5.02, including duly executing and delivering
termination statements for filing in all relevant jurisdictions.

     5.03. Possession of Collateral. So long as no Event of Default has
occurred and is continuing, Borrower shall remain in full possession, enjoyment
and control of the Collateral (except only as may be otherwise required by
Lender for perfection of its security interest therein) and to manage, operate
and use the same and each part thereof with the rights and franchises
appertaining thereto; provided, however, that the possession, enjoyment,
control and use of the Collateral shall at all times be subject to the
observance and performance of the terms of this Agreement.

     5.04. Markings on the Collateral. If requested at any time by Lender,
Borrower shall place in a conspicuous location on each item of Collateral a
notice (to be supplied by Lender) which reads as follows:

                          "MMC/GATX Partnership No. 1
                                  Lienholder"

Such notice shall not be removed (or if removed or damaged such notice shall be
replaced) until the security interest in favor of Lender in such item of
Collateral is terminated pursuant to this Agreement.

     6.01. Affirmative Covenants.

           (a) Payment of Taxes, etc. Borrower shall pay and discharge all
taxes, assessments and governmental charges or levies imposed upon it or upon
its income or profits, or upon any properties belonging to it, prior to the
date on which penalties attach thereto, and all lawful claims which, if unpaid,
might become a Lien upon any of its properties; provided that there shall be no
requirement to pay any such tax, assessment, charge, levy or claim (i) which is
being contested in good faith and by appropriate proceedings or which presents
no risk of seizure, forfeiture, levy or other event which could jeopardize any
Collateral or (ii) for which payment in full is bonded or reserved in
Borrower's financial statements.

           (b) Inspection Rights. Upon 5 Business Days' notice, Borrower shall
permit Lender or any of its agents or representatives to inspect the Equipment,
to examine and make copies of and abstracts from the records and books of
account of, and visit the properties of, Borrower and to discuss the affairs,
finances and accounts of Borrower with any of its officers or directors
relating in each case to Lender's capacity as lender and secured party
hereunder and with respect to the Collateral. Lender shall not conduct such
inspections more than three times per year.

           (c) Use; Maintenance.

               (i) Borrower shall, at its expense, make all necessary site
preparations and cause the Collateral to be operated in accordance with any
applicable manufacturer's manuals or instructions. So long as no Default or
Event of Default has occurred and is continuing, Borrower shall have the right
to quietly possess and use the Collateral as provided herein without
interference by Lender.

               (ii) Borrower shall, at its expense, maintain the Collateral in
good condition, reasonable wear and tear excepted, and comply in all material
respects with all laws, rules and regulations to which the use and operation of
the Collateral may be or become subject. Such obligation shall extend to repair
and replacement of any partial loss or damage to the Collateral, regardless of
the cause. All parts furnished in connection with such maintenance or repair
shall immediately become part of the Collateral. All such maintenance, repair
and replacement services shall be paid for and discharged by

                                      10
<PAGE>   11
Borrower with the result that no Lien will attach to the Collateral. All parts
or accessories attached to or made part of the Collateral shall be new,
fabricated or rebuilt and in any case shall be consistent with the applicable
specifications, if any, prescribed by the manufacturer of the affected
Collateral.

     (d) Insurance. Unless such provisions are amended pursuant to the terms of
any Loan Terms Schedule:

          (i)  Borrower shall obtain and maintain for the Term, at its own
expense, (x) "all risk" insurance against loss or damage to the Collateral and
(y) commercial general liability insurance (including contractual lability,
products liability and completed operations coverages) reasonably satisfactory
to Lender; provided that product liability insurance shall not be required
until Borrower conducts prospective human clinical trials of any of its
products or provides clinical laboratory services for a third party. The amount
of the "all risk" insurance shall be the greater of (x) the replacement value
of the Collateral (as new) or (y) the Loan Value of the Loan Amount applicable
to each Loan.

          (ii) The deductible with respect to "all-risk" insurance required by
clause (x) above and product liability insurance required by clause (y) above
shall not exceed $25,000; otherwise there shall be no deductible with respect
to any insurance required to be maintained hereunder. The amount of commercial
general liability insurance (other than products liability coverage and
completed operations insurance) required by clause (y) above shall be at least
$5,000,000 per occurrence. The amount of the products liability and complete
operations insurance required by clause (y) above shall be at least $5,000,000
per occurrence. Each "all risk" policy shall: (x) name Lender as sole loss
payee with respect to the Equipment, (y) provide for each insurer's waiver of
its right of subrogation against Lender, and (z) provide that such insurance
(A) shall not be invalidated by any action of, or breach of warranty by,
Borrower of a provision of any of its insurance policies, and (B) shall waive
set-off, counterclaim or offset against Lender. Each liability policy shall (w)
name Lender as an additional insured an (x) provide that such insurance shall
have cross-liability and severability of interest endorsements (which shall not
increase the aggregate policy limits of Borrower's insurance). All insurance
policies shall (y) provide that Borrower's insurance shall be primary without a
right of contribution of Lender's insurance, if any, or any obligation on the
part of Lender to pay premiums of Borrower, and (z) shall contain a clause
requiring the insurer to give Lender at least 30 days' prior written notice of
its cancellation (other than cancellation for non-payment for which 10 days'
notice shall be sufficient). Borrower shall on or prior to the first Funding
Date and prior to each policy renewal, furnish to Lender certificates of
insurance or other evidence satisfactory to Lender that such insurance coverage
is in effect. Upon the expiration or termination of the Term, Lender shall
cease to be the sole payee with respect to the Equipment and shall cease to be
named as an additional insured on each insurance policy relating to the
Collateral.

     (e) Loss: Damage; Destruction and Seizure.

          (i)  Borrower shall bear the risk of the Collateral being lost,
stolen, destroyed, damaged or seized by a governmental authority for any reason
whatsoever at any time until the expiration or termination of the Term.

          (ii) Except as set forth in Section 6.01(e)(iii), if during the Term
any item of Equipment is lost, stolen, destroyed, damaged or seized by a
governmental authority for a period equal to at least the remainder of the Term
(an "Event of Loss"), then Lender shall receive from the proceeds of insurance
maintained pursuant to Section 6.01(d), from any award paid by the seizing
governmental authority or, to the extent not received from the proceeds of
insurance or award or both, from Borrower, on or before the Payment Date next
succeeding such Event of Loss, an amount equal to the sum of: (x) all accrued
and unpaid Scheduled Payments with respect to such Loan due prior to the next
such Payment Date, (y) a prepayment in an amount equal to the Loan Value, with
respect to such Loan, multiplied by the Stated Cost of each affected item of
Collateral and (z) all other sums, if any, that shall have become due and
payable hereunder with respect to such Loan, including interest at the Default
Rate with respect to any past due amounts. On the date of receipt by Lender of
the amount specified hereinabove with respect to each such item of Collateral
subject to an Event of Loss, the provisions of this Agreement shall terminate

                                       11
<PAGE>   12
as to such Collateral. Any proceeds of insurance maintained by Borrower
pursuant to Section 6.10(d) and received by Borrower shall be paid to Lender
promptly upon their receipt by Borrower. If any proceeds of insurance or awards
received from governmental authorities are in excess of the amount owed under
this Section 6.01(e), Lender shall promptly remit to Borrower the amount
in excess of the amount owed to Lender.

          (iii) So long as no Event of Default has occurred and is continuing,
any proceeds of insurance maintained pursuant to Section 6.01(d) received by
Lender or Borrower with respect to an item of Collateral the repair of which is
practicable shall, at the election of Borrower, be applied either to the repair
or replacement of such Collateral or, upon Lender's receipt of evidence of the
repair or replacement of the Collateral reasonably satisfactory to Lender, to
the reimbursement of Borrower for the cost of such repair or replacement. All
replacement parts and equipment acquired by Borrower in replacement of
Collateral pursuant to this Section 6.01(e)(iii) shall immediately become part
of the Collateral upon acquisition by Borrower. Borrower shall take such actions
and provide such documentation as may be reasonably requested by Lender to
protect and preserve Lender's first priority security interest and otherwise to
avoid any impairment of Lender's rights under the Operative Documents, in
connection with such repair or replacement.

     7.01. Negative Covenants. So long as the Loans or the Note or other
amounts hereunder remain outstanding, Borrower shall not:

          (a) Collateral Control. Subject to its rights under Article V, (i)
terminate, waive or release any material right with respect to any Collateral or
remove any item of Collateral from Borrower's facility located at the address
set forth in Section 10.5(a) or such other address set forth in any Loan Terms
Schedule, or (ii) affix or attach or permit to be affixed or attached to any
item of Collateral any other item of property owned by Borrower or any other
lender, lessor or financing party which is not readily identifiable or separable
without any damage to such item of Collateral, without Lender's prior written
consent, which consent shall not be unreasonably withheld.

          (b) Liens. Create, incur, assume or suffer to exist any Lien of any
kind upon any Collateral, whether now owned or hereafter acquired, except
Permitted Liens (other than Permitted Liens identified in clause (e) of the
definition thereof); or create, incur, assume or suffer to exist a Lien upon any
Intellectual Property to secure indebtedness to another lender or otherwise for
borrowed money.

          (c) Other Dispositions of Collateral. Convey, sell, lease or otherwise
dispose of all or any part of the Collateral to any Person, except for Equipment
in which Lender shall have released its security interest pursuant to Section
5.02.

     8.01. Closing. At the time of execution and delivery of this Agreement,
Borrower shall have duly executed and/or delivered to Lender the items set forth
in Part I of Schedule 3.

     8.02. Other Conditions. The obligation of Lender to make each Loan shall be
subject to the execution and/or delivery to Lender of each of the items set
forth in Part I of Schedule 3 and the satisfaction of by Borrower of each
condition set forth in Part II of Schedule 3.

     8.03. Covenant to Deliver. Borrower agrees (not as a condition but as a
covenant) to deliver to Lender each item required to be delivered to Lender as
a condition to each Loan, if such Loan is advanced. Borrower expressly agrees
that the extension of such Loan prior to the receipt by Lender of any such item
shall not constitute a waiver by Lender of Borrower's obligation to deliver
such item.

     9.01. Events of Default. An "Event of Default" shall mean the occurrence
of one or more of the following described events: (a) Borrower shall (i) default
in the payment of principal of, or interest on, or fail to make the Final
Payment on any Loan when the same is due, or (ii) default in the payment of any
expense or other amount payable hereunder or thereunder for five (5) days after
receipt of written notice from Lender that the same is due; or (b) any
representation or warranty made herein or on a Funding

                                      12
<PAGE>   13
Date by Borrower in any Operative Document, or any certificate or financial
statement furnished pursuant to the provisions of any Operative Document, shall
prove to have been false or misleading in any material respect as of the time
made or furnished; or (c) Borrower shall default in the performance of any
covenant, agreement or obligation (other than a covenant, agreement or
obligation referred to in Section 9.01(a) or Section 9.01(e)) contained in any
Operative Document (other than the Warrant) and Borrower shall fail to cure
within thirty (30) days after receipt of written notice from Lender any default
in the performance of any such covenant, agreement or obligation contained
therein; or (d) Borrower shall have breached the terms of the Warrant and the
same has not been cured within five (5) days after notice thereof; or (e)
Borrower fails to maintain the insurance coverage required under Section
6.01(d); or (f) any Operative Document shall in any material respect cease to
be a legal, valid and binding obligation of Borrower enforceable in accordance
with its terms; or (g) a proceeding shall have been instituted in a court of
competent jurisdiction seeking a decree or order for relief in respect of
Borrower in an involuntary case under any applicable bankruptcy, insolvency or
other similar law now or hereafter in effect, or for the appointment of a
receiver, liquidator, assignee, custodian, trustee (or similar official) of
Borrower or for any substantial part of its property, or for the winding-up or
liquidation of its affairs, and such proceeding shall remain undismissed or
unstayed and in effect for a period of sixty (60) consecutive days or such
court shall enter a decree or order granting the relief sought in such
proceeding; or (h) Borrower shall commence a voluntary case under any
applicable bankruptcy, insolvency or other similar law now or hereafter in
effect, shall consent to the entry of an order for relief in an involuntary
case under any such law, or shall consent to the appointment of or taking
possession by a receiver, liquidator, assignee, trustee, custodian (or other
similar official) of Borrower or for any substantial part of its property, or
shall make a general assignment for the benefit of creditors, or shall fail
generally to pay its debts as they become due, or shall take any corporate
action in furtherance of any of the foregoing.

     9.02. Consequences of Event of Default. (a) If an Event of Default
specified under clauses (a) through (f) of Section 9.01 shall occur and be
continuing, Lender may (i) declare the Loan Value of the Loan Amount of each
Loan and all other liabilities of Borrower hereunder and under the other
Operative Documents to be immediately due and payable, without presentment,
demand, protest or further notice of any kind, all of which are hereby
expressly waived, and (ii) terminate its commitment to make Loans hereunder
and under the Note and terminate any commitment to advance money or extend
credit to or for the benefit of Borrower pursuant to any other agreement or
commitment extended by Lender to Borrower. (b) If an Event of Default
specified under clause (g) or (h) of Section 9.01 shall occur, then immediately
and without notice (i) the Loan Value of the Loan Amount of each Loan and all
other liabilities of Borrower hereunder and under the other Operative Documents
shall automatically become due and payable, without presentment, demand,
protest or notice of any kind, all of which are hereby expressly waived, and
(ii) Lender's commitment hereunder to make the Loans and any other commitment
of Lender to Borrower to advance money or extend credit pursuant to any other
agreement or commitment shall be terminated.

     9.03. Rights Regarding Collateral. Borrower agrees that when any Event of
Default has occurred and is continuing, Lender shall have the rights, options,
duties and remedies of a secured party as permitted by law and, in addition to
and without limiting the foregoing, Lender may exercise any one or more or all,
and in any order, of the remedies herein set forth, including the following:
(a) Lender, personally or by agents or attorneys, shall have the right (subject
to compliance with any applicable mandatory legal requirements) to require
Borrower to assemble the Collateral and make it available to Lender at a place
to be designated by Lender or to take immediate possession of the Collateral,
or any portion thereof, and for that purpose may pursue the same wherever it
may be found, and may enter any of premises of Borrower, with or without
notice, demand, process of law or legal procedure, to the extent permitted by
applicable law, and search for, take possession of, remove, keep and store the
same, or use and operate or lease the same until sold; (b) Lender may, if at
the time such action may be lawful and always subject to compliance with any
mandatory legal requirements, either with or without taking possession and
either before or after taking possession, without instituting any legal
proceedings whatsoever, having first given notice of such sale by registered or
certified mail to Borrower once at least ten (10) days prior to the date of
such sale, and having first given any other notice which may be required by
law, sell and dispose of the Collateral, or any part thereof, at a private sale
or at public auction, to the

                                      13

<PAGE>   14

highest bidder, in one lot as an entirety or in separate lots, and either for
cash or on credit and on such terms as Lender may determine, and at any place
(whether or not it be the location of the Collateral or any part thereof)
designated in the notice referred to above. To the extent permitted by
applicable law, any such sale or sales may be adjourned from time to time by
announcement at the time and place appointed for such sale or sales, or for any
such adjourned sale or sales, without further published notice, and Borrower,
Lender or the holder or holders of the Note, or of any interest therein, may
bid and become the purchaser at any such sale; (c) Lender may liquidate any
Collateral pledged pursuant to Section 5.01(c) and apply the proceeds thereof
to any outstanding obligations; and (d) Lender may proceed to protect and
enforce this Agreement and the other Operative Documents by suit or suits or
proceedings in equity, at law or in bankruptcy, and whether for the specific
performance of any covenant or agreement herein contained or in execution or
aid of any power herein granted; or for foreclosure hereunder, or for the
appointment of a receiver or receivers for any real property security or any
part thereof, or for the recovery of judgment for the Obligations or for the
enforcement of any other proper, legal or equitable remedy available under
applicable law.

     9.04. Waiver by Borrower. Upon the occurrence of an Event of Default, to
the extent permitted by law, Borrower covenants that it will not at any time
insist upon or plead, or in any manner whatsoever claim or take any benefit or
advantage of, any stay or extension law now or at anytime hereafter in force,
nor claim, take nor insist upon any benefit or advantage of or from any law now
or hereafter in force providing for the valuation or appraisement of the
Collateral or any part thereof prior to any sale or sales thereof to be made
pursuant to any provision herein contained, or to the decree, judgment or order
of any court of competent jurisdiction; nor, after such sale or sales, claim or
exercise any right under any statute now or hereafter made or enacted by any
state or otherwise to redeem the property so sold or any part thereof, and, to
the full extent legally permitted, except as to rights expressly provided
herein, hereby expressly waives for itself and on behalf of each and every
Person, except decree or judgment creditors of Borrower, acquiring any interest
in or title to the Collateral or any part thereof subsequent to the date of
this Agreement, all benefit and advantage of any such law or laws, and
covenants that it will not invoke or utilize any such law or laws or otherwise
hinder, delay or impede the execution of any power herein granted and delegated
to Lender, but will suffer and permit the execution of every such power as
though no such power, law or laws had been made or enacted.

     9.05. Effect of Sale. Any sale of Collateral, whether under any power of
sale available to Lender or by virtue of judicial proceedings, shall operate to
divest all right, title, interest, claim and demand whatsoever, either at law
or in equity, of Borrower in and to the property sold, and shall be a perpetual
bar, both at law and in equity, against Borrower, its successors and assigns,
and against any and all persons claiming the property sold or any part thereof
under, by or through Borrower, its successors or assigns.

     9.06. Application of Collateral Proceeds. The proceeds and/or avails of
the Collateral, or any part thereof, and the proceeds and the avails of any
remedy hereunder (as well as any other amounts of any kind held by Lender at
the time of, or received by Lender after, the occurrence of an Event of Default
hereunder) shall be paid to and applied as follows: (a) First, to the payment
of reasonable costs and expenses, including all amounts expended to preserve
the value of the Collateral, of foreclosure or suit, if any, and of such sale
and the exercise of any other rights or remedies, and of all proper fees,
expenses, liability and advances, including reasonable legal expenses and
attorneys' fees, incurred or made hereunder by Lender; (b) Second, to the
payment to Lender of the amount then owing or unpaid on the Note for Scheduled
Payments and the Loan Value of the Loan Amount with respect to each Loan, and
in case such proceeds shall be insufficient to pay in full the whole amount so
due, owing or unpaid upon the Note, then first, to the unpaid interest thereon,
second, to unpaid principal thereof and third, to the remaining balance of the
Loan Value of the Loan Amount with respect to each Loan; such application to be
made upon presentation of the Note, and the notation thereon of the payment, if
partially paid, or the surrender and cancellation thereof, if fully paid; (c)
Third, to the payment of other amounts then payable to Lender under any of the
Operative Documents; and (d) Fourth, to the payment of the surplus, if any, to
Borrower, its successors and assigns, or to whomsoever may be lawfully entitled
to receive the same.

                                      14

<PAGE>   15
     9.07. Reinstatement of Rights. If Lender shall have proceeded to enforce
any right under this Agreement or any other Operative Document by foreclosure,
sale, entry or otherwise, and such proceedings shall have been discontinued or
abandoned for any reason or shall have been determined adversely, then and in
every such case (unless otherwise ordered by a court of competent
jurisdiction), Lender shall be restored to its former position and rights
hereunder with respect to the property subject to the security interest created
under this Agreement.

     10.01. Modifications, Amendments or Waivers. The provisions of any
Operative Document may be modified, amended or waived only by a written
instrument signed by the parties thereto.

     10.02. No Implied Waivers; Cumulative Remedies; Writing Required. No delay
or failure of Lender in exercising any right, power or remedy hereunder shall
affect or operate as a waiver thereof; nor shall any single or partial exercise
thereof or any abandonment or discontinuance of steps to enforce such a right,
power or remedy preclude any further exercise thereof or of any other right,
power or remedy. The rights and remedies hereunder of Lender are cumulative and
not exclusive of any rights or remedies which it would otherwise have. Any
waiver, permit, consent or approval of any kind or character on the part of
Lender of any breach or default under this Agreement or any such waiver of any
provision or condition of this Agreement must be in writing and shall be
effective only in the specified instance and to the extent specifically set
forth in such writing.

     10.03. Expenses; Indemnification. Borrower agrees upon demand to pay or
reimburse Lender for all liabilities, obligations and out-of-pocket expenses,
including reasonable fees and expenses of counsel for Lender, from time to time
arising in connection with the enforcement or collection of sums due under the
Operative Documents. Borrower shall indemnify, reimburse and hold Lender, each
of Lender's partners, and each of their respective successors, assigns, agents,
officers, directors, shareholders, servants, agents and employees harmless from
and against all liabilities, losses, damages, actions, suits, demands, claims
of any kind and nature (including claims relating to environmental discharge,
cleanup or compliance), all costs and expenses whatsoever to the extent they
may be incurred or suffered by such indemnified party in connection therewith
(including reasonable attorneys' fees and expenses), fines, penalties (and
other charges of applicable governmental authorities), licensing fees relating
to any item of Collateral, damage to or loss of use of property (including
consequential or special damages to third parties or damages to Borrower's
property), or bodily injury to or death of any person (including any agent or
employee of Borrower) (each, a "Claim"), directly or indirectly relating to or
arising out of the use of the proceeds of the Loans, including acquisition,
use, ownership, operation, possession, control, storage, return or condition of
any item of Equipment financed by a Loan or constituting Collateral (regardless
of whether such item of Equipment is at the time in the possession of
Borrower), the falsity of any representation or warranty of Borrower or
Borrower's failure to comply with the terms of this Agreement or any other
Operative Document during the Term. The foregoing indemnity shall cover,
without limitation, (i) any Claim in connection with a design or other defect
(latent or patent) in any item of Equipment financed by a Loan or constituting
Collateral, (ii) any Claim resulting from the presence on or under or the
escape, seepage, leakage, spillage, discharge, emission or release of any
Hazardous Materials from any item of Equipment financed by a Loan or
constituting Collateral, including any Claims asserted or arising under any
Environmental Law, or (iii) any Claim for negligence or strict or absolute
liability in tort; provided, however, that Borrower shall not indemnify Lender
for any liability incurred by Lender as a direct and sole result of Lender's
gross negligence or willful misconduct. Such indemnities shall continue in full
force and effect, notwithstanding the expiration or termination of this
Agreement. Upon Lender's written demand, Borrower shall assume and diligently
conduct, at its sole cost and expense, the entire defense of Lender, each of
its partners, and each of their respective, agents, employees, directors,
officers, shareholders, successors and assigns against any indemnified Claim
described in this Section 10.03. Borrower shall not settle or compromise any
Claim against or involving Lender without first obtaining Lender's written
consent thereto, which consent shall not be unreasonably withheld.

     10.04. Waivers. (a) Borrower shall give Lender written notice within one
hundred eighty (180) days of obtaining knowledge of the occurrence of any claim
or cause of action it believes it has, or may seek to assert to allege against
Lender whether such claim is based in law or equity, arising under or

                                       15
<PAGE>   16
related to this Agreement or any of the other Operative Documents or to the
transactions contemplated hereby or thereby, or any act or omission to act by
Lender with respect hereto or thereto, and that if it shall fail to give such
notice to Lender with regard to any such claim or cause of action. Borrower
shall be deemed to have waived, and shall be forever barred from bringing or
asserting such claim or cause of action in any suit, action or proceeding in
any court or before any governmental agency or authority or any arbitrator. (b)
NOTWITHSTANDING ANYTHING TO THE CONTRARY CONTAINED IN THIS AGREEMENT OR
ANYWHERE ELSE, BORROWER AGREES THAT IT SHALL NOT SEEK FROM LENDER UNDER ANY
THEORY OF LIABILITY (INCLUDING ANY THEORY IN TORTS), ANY SPECIAL, INDIRECT,
CONSEQUENTIAL OR PUNITIVE DAMAGES.

     10.05. Notices; Payments.

            (a) All notices and other communications given to or made upon any
party hereto in connection with this Agreement shall be in writing (including
telexed, telecopied or telegraphic communication) and mailed (by certified or
registered mail), telexed, telegraphed, telecopied or delivered to the
respective parties, as follows:

            Borrower: At the address set forth on the signature page of the
                      applicable Loan Terms Schedule.

            Lender:   MMC/GATX PARTNERSHIP NO. 1
                      c/o GATX Capital Corporation
                      Four Embarcadero Center
                      Suite 2200
                      San Francisco, California 94111
                      Telephone No.: 415-955-3200
                      Telecopier No.: 415-955-3493
                      Attention: Contract Administration

with a copy of all financial information to:

                      MEIER MITCHELL & COMPANY
                      4 Orinda Way, Suite 200B
                      Orinda, California 94563

or in accordance with any subsequent written direction from either party to the
other. All such notices and other communications shall, except as otherwise
expressly herein provided, be effective when received; or in the case of
delivery by messenger or overnight delivery service, when left at the
appropriate address.

            (b) Unless Lender specifies otherwise in writing, all payments
                shall be made to:

                      GATX Capital Corporation

                      and mailed to:
                      NationsBank
                      P.O. Box 198592
                      Atlanta, Georgia 30384-8592
                      Reference: ViroLogic, Inc. and applicable invoice number

     10.06. Termination. This Agreement shall terminate on the latest Maturity
Date; provided, however, that the termination of this Agreement shall not
affect any of the rights and remedies of Lender hereunder, it being understood
and agreed that all such rights and remedies shall continue in full force and
effect until payment of all amounts owed to Lender under or in connection with
the Operative Documents, whether on account of principal, interest, fees or
otherwise.

     10.07. Severability. If any provision of any Operative Document is held
invalid or unenforceable to any extent or in any application, the remainder of
such Operative Document and all other Operative

                                      16
<PAGE>   17
Documents, or the application of such provision to different Persons or
circumstances or in different jurisdictions, shall not be affected thereby.

     10.08. Survival. All representations, warranties, covenants and agreements
of Borrower contained herein or made in writing in connection herewith shall
survive the execution and delivery of the Operative Documents, the making of
Loans hereunder, the granting of security and the issuance of the Note.

     10.09. Governing Law. This Agreement, the other Operative Documents and the
rights and obligations of the parties hereto and thereto shall be governed by
and construed and enforced in accordance with the laws of the State of
California. Any action to enforce this Agreement against Borrower may be brought
in California or, with regard to Collateral, may also be brought wherever such
Collateral is located.

     10.10. Successors and Assigns. This Agreement and the other Operative
Documents shall be binding upon and inure to the benefit of Lender, all future
holders of the Note, Borrower and their respective successors and permitted
assigns. In the event of a proposed statutory merger of the Borrower into
another corporation or a proposed sale or transfer by the Borrower of all or
substantially all of its assets to a third party business entity, then, provided
that (i) the Borrower is not in default under this Agreement or under any other
agreement between Borrower and Lender, (ii) Lender or its assignee has been
given sufficient advance written notice of the proposed merger, sale, or
transfer together with the necessary background as to the legal status,
financial and credit worthiness of the third party to the merger sale or
transfer (collectively, a "Transferee") and the Lender or its assignee within
ten days of receipt of such written notice has approved such financial and
credit worthiness of the Transferee in accordance with its then existing credit
criteria, Lender agrees that it will not unreasonably withhold its consent to
any such transfer or assignment of this Agreement (and the transfer of the
Equipment to such Transferee), provided, that (a) the said Transferee assumes
all of the Borrower's obligations under this Agreement in form satisfactory to
Lender or its assignee (and expressly releasing the Borrower), (b) the Lender is
assured that its first perfected security interest in the Equipment will
continue in full force and effect and the Transferee executes such UCC
Financing Statements as may be necessary to accomplish the same and (c) Lender
is assured that the Equipment will be adequately covered by insurance during any
move thereof, provided, further, that should Lender reasonably withhold consent,
Borrower may prepay the Loans in whole at a prepayment price equal to the
principal amount of the Loans plus interest accrued thereon through and
including the date of such prepayment, plus a premium equal to a Make-Whole
Premium. Lender may sell to any other financial entity (a "Participant")
participation interests in Lender's rights under this Agreement and the other
Operative Documents. Lender may disclose the Operative Documents and any other
financial or other information relating to Borrower or any Subsidiary to any
potential Participant, provided that such Participant agrees to protect the
confidentiality of such documents and information using the same measures that
it uses to protect its own confidential information.

     10.11. Counterparts. This Agreement may be executed in any number of
counterparts and by different parties hereto on separate counterparts, each of
which, when so executed and delivered, shall be an original, but all such
counterparts shall together constitute one and the same instrument.

     10.12. Further Assurances. Borrower will, at its own expense, from time to
time do, execute, acknowledge and deliver all and every further acts, deeds,
conveyances, transfers and assurances, and all financing and continuation
statements and similar notices, reasonably necessary or proper for the
perfection of the security interest being herein provided for in the Collateral,
whether now owned or hereafter acquired.

     10.13. Power of Attorney in Respect of the Collateral. Borrower does
hereby irrevocably appoint Lender (which appointment is coupled with an
interest), the true and lawful attorney-in-fact of Borrower with full power of
substitution, for it and in its name (a) to perform (but Lender shall not be
obligated to and shall incur no liability to Borrower or any third party for
failure to perform) any act which Borrower is obligated by this Agreement to
perform, (b) to ask, demand, collect, receive, receipt for, sue for,

                                       17
<PAGE>   18
compound and give acquittance for any and all rents, issues, profits, avails,
distributions, income, payment draws and other sums in which a security
interest is granted under Section 5.01 with full power to settle, adjust or
compromise any claim thereunder as fully as if Lender were Borrower itself, (c)
to receive payment of and to endorse the name of Borrower to any items of
Collateral (including checks, drafts and other orders for the payment of money)
that come into Lender's possession or under Lender's control, (d) to make all
demands, consents and waivers, or take any other action with respect to, the
Collateral, (e) in Lender's discretion, to file any claim or take any other
action or institute proceedings, either in its own name or in the name of
Borrower or otherwise, which Lender may reasonably deem necessary or
appropriate to protect and preserve the right, title and interest of Lender in
and to the Collateral, and (f) to otherwise act with respect thereto as though
Lender were the outright owner of the Collateral; provided, however, that the
power of attorney herein granted shall be exercisable only upon the occurrence
and during the continuation of an Event of Default. Borrower agrees to
reimburse Lender upon demand for all reasonable costs and expenses, including
attorneys' fees and expenses, which Lender may incur while acting as Borrower's
attorney in fact hereunder, all of which costs and expenses are included within
the Obligations.

     IN WITNESS WHEREOF, the parties hereto, by their officers thereunto duly
authorized, have executed this Agreement as of the day and year first above
written.

                                             VIROLOGIC, INC.

                                             By: /s/ MARTIN H. GOLDSTEIN
                                                 --------------------------
                                             Name: Martin H. Goldstein
                                                   ------------------------
                                             Title: Pres. & CEO
                                                   ------------------------

                                             MMC/GATX PARTNERSHIP NO. 1

                                             By:   Meier Mitchell & Company,
                                                   as General Partner

                                             By:
                                                 --------------------------
                                             Name:
                                                   ------------------------
                                             Title:
                                                    -----------------------

                                      18
<PAGE>   19
compound and give acquittance for any and all rents, issues, profits, avails,
distributions, income, payment draws and other sums in which a security
interest is granted under Section 5.01 with full power to settle, adjust or
compromise any claim thereunder as fully as if Lender were Borrower itself, (c)
to receive payment of and to endorse the name of Borrower to any items of
Collateral (including checks, drafts and other orders for the payment of money)
that come into Lender's possession or under Lender's control, (d) to make all
demands, consents and waivers, or take any other action with respect to, the
Collateral, (e) in Lender's discretion, to file any claim or take any other
action or institute proceedings, either in its own name or in the name of
Borrower or otherwise, which Lender may reasonably deem necessary or
appropriate to protect and preserve the right, title and interest of Lender in
and to the Collateral, and (f) to otherwise act with respect thereto as though
Lender were the outright owner of the Collateral; provided, however, that the
power of attorney herein granted shall be exercisable only upon the occurrence
and during the continuation of an Event of Default. Borrower agrees to
reimburse Lender upon demand for all reasonable costs and expenses, including
attorneys' fees and expenses, which Lender may incur while acting as Borrower's
attorney in fact hereunder, all of which costs and expenses are included within
the Obligations.

     IN WITNESS WHEREOF, the parties hereto, by their officers thereunto duly
authorized, have executed this Agreement as of the day and year first above
written.

                                             VIROLOGIC, INC.

                                             By:
                                                 --------------------------
                                             Name:
                                                   ------------------------
                                             Title:
                                                   ------------------------

                                             MMC/GATX PARTNERSHIP NO. 1

                                             By:   Meier Mitchell & Company,
                                                   as General Partner

                                             By: /s/ JAMES V. MITCHELL
                                                 --------------------------
                                             Name: James V. Mitchell
                                                   ------------------------
                                             Title: Secretary
                                                    -----------------------

                                      18
<PAGE>   20

SCHEDULES
     1  Loan Terms Schedule
     2  Existing Liens
     3  Conditions Precedent

EXHIBITS
     A  Secured Promissory Note
     ????
     C  Warrant
     D  Form of Opinion of Counsel

                                       19
<PAGE>   21
                                   SCHEDULE 1

                          LOAN TERMS SCHEDULE NO. ___

This Loan Terms Schedule No. __ (this "Schedule"), dated as of __________, 199_
is part of the Loan and Security Agreement, dated as of January 30, 1998 (the
"Loan Agreement"), between MMC/GATX PARTNERSHIP NO. 1 ("Lender") and VIROLOGIC,
INC. ("Borrower") and is incorporated therein by reference. The terms used in
this Schedule shall have the meanings given to them in the Loan Agreement
unless otherwise defined herein.

1.   The following terms are applicable to the Loan described by this Schedule:

     Loan Funding Date: ____________, 199_

     Initial Loan Amount: $_________

     Loan Factor: _____%

     Original Scheduled Payment Amount(1): $_________

     Date of First Scheduled Payment: ____________, 199_

     The schedule of Loan Values is attached to this Loan Terms Schedule as
     Annex B.

2.   Borrower shall pay to Lender an Interim Payment in the amount of $_______.
The Interim Payment is due and payable on ____________, 199_.

3.   The Commitment Fee shall be applied first to Lender's expenses, including
the fees and expenses of Lender's counsel in connection with the preparation
and negotiation of the Agreement and the other Operative Documents, such fees
to be capped at $5,000. The balance, if any, of the Commitment Fee shall be
applied on a pro rata basis (using the ratio of each Loan Amount to the total
Credit Amount) toward the first payment due from Borrower on each Loan
hereunder on the respective Funding Dates. If, on or prior to the Commitment
Termination Date, Borrower shall not have borrowed under this Agreement Loans
aggregating in an original principal amount equal to the Credit Amount, then
Lender shall retain any portion of the Commitment Fee not applied as set forth
in this Section 3.

4.   Borrower certifies that the proceeds of the Loan requested hereby will be
used for the purposes described in Section 2.02(a) of the Loan Agreement and
that the Equipment being financed with or which serves as Collateral for such
Loan is listed on Annex A hereto, which Annex A shall automatically be deemed
to be included in and amend the definition of "Collateral" under the Loan
Agreement as if such Annex A were set forth in full therein. Borrower hereby
confirms that it has granted and does further grant to Lender a security
interest in such Collateral including the Equipment specifically described on
Annex A hereto.

5.   The proceeds of the Loan should be wire transferred to Borrower as follows:

     Bank Name: Bank of America
     Bank Address: 444 Castro Street, Box 580, Mountain View, CA 94042
     Account No.: 0144-8-08321
     Routing No. (if any): 121000358
     For Account of: ViroLogic, Inc.
     Attention: Lucille Young

_______________
(1) The amount of each Scheduled Payment will change if the Loan Amount
    changes.

                                       20
<PAGE>   22
6.   Borrower certifies that (a) the foregoing information is true and correct
and authorizes Lender to endorse on the grid attached to the Note, the Loan
Rate applicable to the Loan contemplated in this Loan Terms Schedule and the
principal amount set forth as the "Initial Loan Amount" in paragraph 1 above;
(b) except as set forth in the Schedule of Exceptions attached hereto as Annex
C, the representations and warranties made by Borrower in Article III of the
Loan Agreement and in the other Operative Documents are true and correct on the
date hereof; (c) Borrower is in compliance with the covenants and the
requirements contained in Articles IV, VI and VII of the Loan Agreement; and
(d) all conditions contained in Article VIII of the Loan Agreement to the
making of the Loan described in this Loan Terms Schedule have been satisfied.

7.   All payments with respect to the Loan described on this Schedule shall be
made to Lender c/o GATX Capital Corporation, as Agent, Box 71316, Chicago,
Illinois 60694 unless otherwise indicated in a writing signed by Lender.

This Loan Terms Schedule is hereby duly executed by the parties hereto as of
the date first written above.

MMC/GATX PARTNERSHIP NO. 1
By Meier Mitchell & Company, as General Partner

By
   --------------------------------------------
Name
     ------------------------------------------
Title
      -----------------------------------------

VIROLOGIC, INC.

By
   --------------------------------------------
Name
     ------------------------------------------
Title
      -----------------------------------------

Borrower's address for notices:
270 E. Grand Avenue
South San Francisco, CA  94080

Attention: Martin H. Goldstein

                                      21

<PAGE>   23
                                    ANNEX A
                                       TO
                              LOAN TERMS SCHEDULE

     The Equipment being financed with or which serves as collateral for the
Loan described on the Loan Terms Schedule to which this Annex A is attached is
listed below.

                              Equipment Collateral

                                      22
<PAGE>   24
                                    ANNEX B
                                       TO
                              LOAN TERMS SCHEDULE

                                  Loan Values

     Payment No.        Payment Date        Loan Value*

     1
     2
     3
     4
     . . .
     [47]
     [48]

________________

* Each Loan Value percentage assumes payment of all Scheduled Payments due on
  or before the indicated Payment Date.

                                      23
<PAGE>   25

                                    ANNEX C
                                       TO
                              LOAN TERMS SCHEDULE

                             Schedule of Exceptions

                                      24

<PAGE>   26
                                   Schedule 2

                                 Existing Liens
<TABLE>
<CAPTION>
     File Number              Type of Filing           Filing Date              Secured Party
     -----------              --------------           -----------              -------------
<S>  <C>                      <C>                      <C>                      <C>
1.   9631860550               Original                 November 8, 1996         Lease Management Services, Inc.
                                                                                2500 Sand Hill Rd, Ste 101
                                                                                Menlo Park, CA 94025

     96327C0402               Amendment                November 22, 1996

     97014C0073               Amendment                January 13, 1997

     97174C0134               Amendment                June 19, 1997

     97289C0110               Amendment                October 14, 1997

2.   9631860578               Original                 November 8, 1996         Taylor Made Office Systems, Inc.
                                                                                1550 Parkside Drive
                                                                                Walnut Creek, CA 94596

3.   9631860592               Original                 November 8, 1996         Taylor Made Office Systems, Inc.
                                                                                1550 Parkside Drive
                                                                                Walnut Creek, CA 94596
</TABLE>

<PAGE>   27
                                  SCHEDULE 3

                             CONDITIONS PRECEDENT

PART I:

     At the time of execution and delivery of this Agreement, there shall also
have been duly executed and delivered to Lender:

     (a) The Note;

     (b) The Warrant;

     (d) A favorable opinion of counsel for Borrower, dated as of the closing
     date, in the form attached hereto as Exhibit D;

     (e) Copies, certified by the Secretary, Assistant Secretary or Chief
     Financial Officer of Borrower as of the closing date, of Borrower's
     charter documents and bylaws and of all documents evidencing corporate
     action taken by Borrower authorizing the execution, delivery and
     performance of the Operative Documents to which Borrower is a party, in
     form and substance satisfactory to Lender and its counsel;

     (f) Good standing certificate from Borrower's state of incorporation and
     the state in which Borrower's principal place of business is located,
     together with certificates of the applicable governmental authorities that
     Borrower is in compliance with the franchise tax laws of each such state,
     each dated as of a recent date;

     (g) Evidence of the insurance coverage required by Section 6.01(d) of this
     Agreement;

     (h) All necessary consents of shareholders and other third parties with
     respect to the execution, delivery and performance of this Agreement, the
     Warrant, the Note and the other Operative Documents;

     (i) An Officer's Certificate in a form reasonably acceptable to Lender
     (the "Officer's Certificate"); and

     (j) All other documents as Lender shall have reasonably requested.

PART II

     On or prior to the Funding Date of each Loan, each of the items set forth
in Part 1 of this Schedule 3 shall have been delivered to Lender and the
following conditions shall have been satisfied or waived by Lender:

     (a) Borrower shall have provided to Lender, with respect to the Equipment
     which is intended to be financed with the proceeds of the Loan to be made
     on such Funding Date, such invoices, bills of sale, receipts, agreements,
     canceled checks, and other documents as Lender shall reasonably request to
     evidence the ownership by Borrower of, the payment in full of the purchase
     price of, and the Original Cost of, such Equipment, each in form and
     substance reasonably satisfactory to Lender; and, except with the prior
     written consent of Lender which shall not be unreasonably withheld, all
     such Equipment shall be Eligible Equipment;

                                      26
<PAGE>   28
     (b) Lender shall have received duly executed Form UCC-1 Financing
     Statements, pledge agreements or other documents and Borrower shall have
     taken such actions, if any, as Lender shall reasonably determine are
     necessary or desirable to perfect and protect its security interest in the
     Collateral;

     (c) Borrower shall have provided to Lender such documents, instruments and
     agreements, including amendments to previously filed financing statements
     terminating "after acquired property" clauses which encompass the
     Equipment, as Lender shall reasonably request to evidence the perfection
     and priority of the security interests granted to Lender pursuant to
     Article V;

     (d) No Event of Default or Default shall have occurred and be continuing;

     (e) Borrower shall have duly executed and delivered to Lender a Loan Terms
     Schedule prepared by Lender;

     (f) In Lender's reasonable, sole discretion, there shall not have occurred
     any material adverse change in the general affairs, management, results of
     operations, condition (financial or otherwise) of the Borrower, or
     prospects of Borrower;

     (g) The representations and warranties contained in this Agreement and the
     other Operative Documents to which Borrower is a party, as modified by any
     Schedule of Exceptions attached to the applicable Loan Terms Schedule as
     Annex C, shall be true and correct in all material respects as if made on
     such Funding Date and the items listed on such Schedule of Exceptions
     shall be reasonably acceptable to Lender;

     (h) Each of the Operative Documents remains in full force and effect;

     (i) Except with the prior consent of Lender which shall not be unreasonably
     withheld, (i) the amount of the requested Loan shall not be less than the
     Minimum Funding Amount; (ii) the amount of the requested Loan when
     aggregated with the amounts of all Loans previously funded shall not
     exceed the Credit Amount; and (iii) the funding of the requested Loan when
     aggregated with the number of previous fundings of Loans shall not exceed
     the Maximum Number of Fundings; and

     (j) The Funding Date of the requested Loan shall not be later than the
     Commitment Termination Date.

                                      27
<PAGE>   29

                                   EXHIBIT A

                            SECURED PROMISSORY NOTE

$3,000,000                                             Dated: January 30, 1998

     FOR VALUE RECEIVED, the undersigned, VIROLOGIC, INC. ("Borrower"), a
Delaware corporation, HEREBY PROMISES TO PAY to the order of MMC/GATX
PARTNERSHIP NO. 1, a California general partnership ("Lender") the principal
amount of Three Million Dollars ($3,000,000) or such lesser amount as shall
equal the aggregate outstanding principal balance of the Loans made by Lender
to Borrower pursuant to the Loan and Security Agreement referred to below (the
"Loan Agreement"), and to pay all other amounts due with respect to each Loan
and the Final Payment amount applicable to each Loan, on the dates and in the
amounts set forth in the Loan Agreement.

     Borrower hereby promises to pay interest to Lender on the unpaid principal
amount of each Loan from the date of such Loan until such principal amount is
paid in full, in the manner, on the dates and at such rates as are specified in
the Loan Agreement.

     The aggregate amount due on each Loan from time to time under this Note
with respect to unpaid principal, accrued interest and the Final Payment is
sometimes expressed in the Loan Agreement as the "Loan Value of the Loan
Amount".

     Principal, interest and all other amounts due with respect to each Loan,
are payable in lawful money of the United States of America to Lender as
follows: GATX Capital Corporation, P.O. Box 71316, Chicago, Illinois 60694, or
upon written notice by Lender to Borrower, Four Embarcadero Center, Suite 2200,
San Francisco, California 94111, in immediately available funds. Each Loan made
by Lender to Borrower and the interest rate applicable thereto, and all
payments made with respect thereto, shall be recorded by Lender and, prior to
any transfer hereof, endorsed on the grid attached hereto which is part of this
Note.

     This Note is the Note referred to in, and is entitled to the benefits of,
the Loan and Security Agreement, dated as of January 30, 1998, between Borrower
and Lender. The Loan Agreement, among other things, (a) provides for the making
of secured Loans by Lender to Borrower from time to time in an aggregate
principal amount not to exceed at any time outstanding the U.S. dollar amount
first above mentioned, the indebtedness of Borrower resulting from each Loan
being evidenced by this Note, and (b) contains provisions for acceleration of
the maturity hereof upon the happening of certain stated events and also for
prepayments prior to the Maturity Date with respect to each Loan only upon the
terms and conditions therein specified.

     This Note and the obligation of Borrower to repay the unpaid principal
amount of the Loans, interest on the Loans, the Final Payments on the Loans and
all other amounts due Lender under the Loan Agreement is secured under the Loan
Agreement.

     Presentment for payment, demand, notice of protest and all other demands
and notices of any kind in connection with the execution, delivery, performance
and enforcement of this Note are hereby waived.

     Borrower shall pay all reasonable fees and expenses, including, without
limitation, reasonable attorneys' fees and costs, incurred by Lender in the
enforcement or attempt to enforce any of Borrower's obligations hereunder not
performed when due. This Note shall be governed by, and construed and
interpreted in accordance with, the laws of the State of California.

                                       28

<PAGE>   30
     IN WITNESS WHEREOF, Borrower has caused this Note to be duly executed by
one of its officers thereunto duly authorized on the date hereof.

                                             VIROLOGIC, INC.

                                             By: /s/ MARTIN H. GOLDSTEIN
                                                 ----------------------------
                                             Name: Martin H. Goldstein
                                                   --------------------------
                                             Title: President & CFO
                                                    -------------------------

                                      29

<PAGE>   31
                LOANS, INTEREST RATE AND PAYMENTS OF PRINCIPAL

<TABLE>
<CAPTION>
<S>         <C>    <C>         <C>             <C>              <C>
                   Principal                     Scheduled
            Date    Amount     Interest Rate   Payment Amount   Notation By
            ----   ---------   -------------   --------------   -----------

</TABLE>

                                      30
<PAGE>   32
                                   EXHIBIT B

                         LANDLORD'S WAIVER AND CONSENT

                                      31
<PAGE>   33
                                 ATTACHMENT 1

                         LEGAL DESCRIPTION OF PREMISES

                          [To Be Provided By Tenant]

                                      34

<PAGE>   34

                                  ATTACHMENT 1

                         LEGAL DESCRIPTION OF PREMISES

Premises are located in a building which in turn is located, along with other
buildings, on the improved real property in the City of South San Francisco,
County of San Mateo, State of California, more particularly described as
follows:

Lots 1, 2, 3 and 4, inclusive, as shown on Parcel Map No. 91-284, "Being a
resubdivision of the parcels described in the deeds to Metal and Thermit
Corporation, recorded in Book 293, at Page 394 of Deeds; in Book 49, at Page
490, Official Records; in Book 77, at Page 415, Official Records; and, except
that parcel described in Book 1352, at Page 373, Official Records," filed on
February 25, 1992, in Book 65 at pages 52 through 55 inclusive of Parcel Maps,
in the Office of the Recorder of the County of San Mateo, California.
<PAGE>   35
                                  ATTACHMENT 1

                         LEGAL DESCRIPTION OF PREMISES

Premises are located in a building which in turn is located, along with other
buildings, on the improved real property in the City of South San Francisco,
County of San Mateo, State of California, more particularly described as
follows:

Lots 1, 2, 3 and 4, inclusive, as shown on Parcel Map No. 91-284, "Being a
resubdivision of the parcels described in the deeds to Metal and Thermit
Corporation, recorded in Book 293, at Page 394 of Deeds; in Book 49, at Page
490, Official Records; in Book 77, at Page 415, Official Records; and, except
that parcel described in Book 1352, at Page 373, Official Records," filed on
February 25, 1992, in Book 65 at pages 52 through 55 inclusive of Parcel Maps,
in the Office of the Recorder of the County of San Mateo, California.

<PAGE>   36
State of ______________ )
                        )
County of______________ )

     On _____________________, 199__ before me, the undersigned, personally
appeared ________________________, personally known to me (or proved to me on
the basis of satisfactory evidence) to be the person(s) whose name(s) is/are
subscribed to the within instrument and acknowledged to me that he/she/they
executed the same in his/her/their authorized capacity(ies), and that by
his/her/their signature(s) on the instrument the person(s), or the entity upon
behalf of which the person(s) acted, executed the instrument.

     WITNESS my hand and official seal.

Signature                         (Seal)
          -----------------------

State of ______________ )
                        )
County of______________ )

     On _____________________, 199__ before me, the undersigned, personally
appeared ________________________, personally known to me (or proved to me on
the basis of satisfactory evidence) to be the person(s) whose name(s) is/are
subscribed to the within instrument and acknowledged to me that he/she/they
executed the same in his/her/their authorized capacity(ies), and that by
his/her/their signature(s) on the instrument the person(s), or the entity upon
behalf of which the person(s) acted, executed the instrument.

     WITNESS my hand and official seal.

Signature                         (Seal)
          -----------------------

                                      35
<PAGE>   37
                                   EXHIBIT C

                                    WARRANT

                                      36

<PAGE>   38

                       FIRST AMENDMENT TO LEASE AGREEMENT

     THIS FIRST AMENDMENT TO LEASE AGREEMENT ("Amendment") is dated as of
February __, 2000, between ARE-Technology Center SSF, LLC, a Delaware limited
liability company ("Landlord"), and Virologic, Inc., a California corporation
("Tenant").

     A.   Trammell Crow Northern California Development, Inc. ("Original
Landlord") and Tenant entered into that certain Lease Agreement dated as of
November 23, 1999 (the "Lease"), with respect to certain premises to be located
at 335 Oyster Point Boulevard, South San Francisco, California (the
"Premises"). Unless otherwise defined in this Amendment, initially-capitalized
terms used herein shall have the meanings set forth in the Lease.

     B.   Original Landlord has contracted to acquire the real property upon
which the Premises are to be located (the "Project"), and intends to assign its
rights to acquire the Project to Landlord.

     C.   In connection with the assignment of its rights to acquire the
Project, Original Landlord intends to assign all of its rights and interest
under the Lease to Landlord.

     D.   Landlord and Tenant wish to amend the Lease as set forth herein.

     NOW THEREFORE, in consideration of the foregoing Recitals, the mutual
covenants and agreements contained herein, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged,
Landlord and Tenant agree, and amend the Lease, as follows:

     1.   Effective Date.

     Landlord and Tenant agree that this Amendment shall be effective upon the
assignment of the Lease to Landlord by Original Landlord, and such assignment
shall be a condition precedent to the effectiveness of this Amendment. The date
upon which the assignment is made and this Amendment becomes effective shall be
called the "Effective Date".

     2.   Transportation Demand Management Program.

     The Lease is hereby amended to include the following provision:

          Landlord and Tenant acknowledge that in connection with the
          development of the Project, the Peninsula Congestion Relief Alliance,
          on behalf of the Inter-City and Multi-City TSM Agencies, San Mateo
          County, will propose a Transportation
<PAGE>   39
          Demand Management ("TDM") program which will focus on reducing traffic
          congestion in the vicinity of the Project. The parties further
          acknowledge that implementation of the TDM program is expected to be
          required by the City of South San Francisco as a condition of approval
          of the development of the Project. Tenant agrees to cooperate with
          Landlord in the implementation of the TDM program, to participate in
          the TDM program, and to pay Tenant's Proportionate Share of the costs
          related to the TDM program.

     3. Counterparts.

     This Amendment may be executed in any number of counterparts, each of
which when so executed and delivered shall be deemed to be an original and all
of which counterparts taken together shall constitute but one and the same
instrument. Signature pages may be detached from the counterparts and attached
to a single copy of this Amendment to physically form one document.

     4. Reaffirmation of Obligations.

     Tenant hereby acknowledges and reaffirms its obligations under the Lease,
as such Lease has been amended by this Amendment, and agrees that any
reference made in any other document to the Lease shall mean the Lease as
amended pursuant to this Amendment. Except as expressly provided herein, the
Lease remains unmodified and in full force and effect. Any breach by Tenant of
this Amendment, including any exhibit hereto, shall constitute a breach and
default by Tenant under the Lease.

     5. Time of Essence.

     Time is of the essence with respect to each provision of this Agreement.

                                       2
<PAGE>   40
     IN WITNESS WHEREOF, Landlord and Tenant have caused this Amendment to be
duly executed and delivered as of the date first above written.

LANDLORD

ARE-Technology Center SSF, LLC,
a Delaware limited liability company

By:   Alexandria Real Estate Equities, L.P.,
      a Delaware limited partnership
      its managing member

      By:   ARE-QRS CORP.,
            a Maryland corporation,
            its general partner

            By:
                ----------------------------
            its:
                ----------------------------

TENANT

VIROLOGIC, INC.,
a California corporation

By: /s/ MARTIN H. GOLDSTEIN
    ----------------------------
Its: President & CFO
     ----------------------------

                                       3<PAGE>   1
                                                                    EXHIBIT 10.6

                              EMPLOYMENT AGREEMENT

        THIS AGREEMENT is entered into as of September 29, 1999, by and between
WILLIAM D. YOUNG (the "EXECUTIVE") and VIROLOGIC, INC., a Delaware corporation
(the "COMPANY").

        1. DUTIES AND SCOPE OF EMPLOYMENT.

               (a) POSITION. For the term of his employment under this Agreement
("EMPLOYMENT"), the Company agrees to employ the Executive in the position of
Chairman and Chief Executive Officer. The Executive shall report to the
Company's Board of Directors (the "Board").

               (b) OBLIGATIONS TO THE COMPANY. During the term of his
Employment, the Executive shall devote his full business efforts and time to the
Company; provided, however, that this shall not preclude the Executive from
serving as a non-executive member of the board of directors of up to three other
companies to the extent such other companies do not compete with the Company and
that such service does not materially impact the ability of the Executive to
fulfill his obligations to the Company. The Executive shall comply with the
Company's policies and rules, as they may be in effect from time to time during
the term of his Employment.

               (c) NO CONFLICTING OBLIGATIONS. The Executive represents and
warrants to the Company that he is under no obligations or commitments, whether
contractual or otherwise, that are inconsistent with his obligations under this
Agreement. The Executive represents and warrants that he will not use or
disclose, in connection with his employment by the Company, any trade secrets or
other proprietary information or intellectual property in which the Executive or
any other person has any right, title or interest and that his employment by the
Company as contemplated by this Agreement will not infringe or violate the
rights of any other person or entity. The Executive represents and warrants to
the Company that he has returned all property and confidential information
belonging to any prior employers.

               (d) COMMENCEMENT DATE. The Executive shall commence Employment
with the Company on a part-time basis starting on October 4, 1999 and shall
commence Employment with the Company on a full-time basis starting on November
1, 1999.

        2. CASH AND INCENTIVE COMPENSATION.

               (a) SALARY. The Company shall pay the Executive as compensation
for his services a base salary at a gross annual rate of $300,000, payable in
accordance with the Company's standard payroll schedule. (The compensation
specified in this Subsection (a), together with any increases in such
compensation that the Company may grant from time to time, is referred to in
this Agreement as "Base Compensation.")

               (b) INCENTIVE BONUSES. The Executive shall be eligible to be
considered for an annual incentive bonus as part of the Company's bonus program
based on objective or subjective criteria established by the Board after
consultation with Executive. Such bonus shall be contingent upon Executive's
continued employment through the end of the bonus period and

                                       1.
<PAGE>   2
Executive shall have no right to any pro rata portion of the bonus. The
determinations of the Board with respect to such bonus shall be final and
binding.

               (c) STOCK GRANTS.

                      (i) In consideration of Executive's service to date as a
member of the Board, and subject to the approval of the Board, the Company shall
grant to the Executive a stock bonus award of 300,000 shares of the Company's
Common Stock. Such stock bonus award shall be granted as soon as reasonably
practicable after the date of this Agreement, but in no event later than
September 30, 1999. The shares of stock granted pursuant to such stock bonus
award shall be fully vested and not subject to repurchase by the Company. In
addition, the Company will pay to Executive a cash bonus in the gross amount of
$180,000 on January 15, 2000 and a cash bonus in the gross amount of $180,000 on
April 15, 2000. Such cash bonuses shall be subject to the Company's standard
withholding policies and procedures.

                      (ii) Subject to the approval of the Board, the Company
shall grant to the Executive an incentive stock option under the Company's 1996
Stock Plan covering 300,000 shares of the Company's Common Stock. Such incentive
stock option shall be granted as soon as reasonably practicable after the date
of this Agreement, but in no event later than October 10, 1999. The per share
exercise price of the option will be equal to the per share fair market value of
the common stock on the date of grant, as determined by the Board of Directors.
The term of such option shall be 10 years, subject to earlier expiration in the
event of the termination of the Executive's Employment. The Executive shall vest
in 60,000 of the option shares on December 31, 1999 and an additional 5,000 of
the option shares on the last day of each month of continuous service
thereafter.

                      (iii) Subject to the approval of the Board, the Company
shall grant the Executive a non-qualified stock option covering 500,000 shares
of the Company's Common Stock. Such option shall be granted as soon as
reasonably practicable after the date of this Agreement, but in no event later
than October 10, 1999. The per share exercise price of the option will be equal
to the per share fair market value of the common stock on the date of grant, as
determined by the Board of Directors. The term of such option shall be 10 years,
subject to earlier expiration in the event of the termination of the Executive's
Employment. The Executive shall vest in 25% of the option shares after the first
12 months of continuous service and shall vest in the remaining option shares in
equal monthly installments over the next three years of continuous service. Such
option will include an early exercise provision that allows Executive to
exercise the option as to vested and unvested shares, subject to a right of
repurchase with respect to unvested shares.

                      (iv) Subject to the approval of the Board, the Company
shall grant the Executive an additional non-qualified stock option covering
500,000 shares of the Company's Common Stock. Such option shall be granted as
soon as reasonably practicable after the date of this Agreement, but in no event
later than October 10, 1999. The per share exercise price of the option will be
equal to the per share fair market value of the common stock on the date of
grant, as determined by the Board of Directors. The term of such option shall be
10 years, subject to earlier expiration in the event of the termination of the
Executive's Employment. The option shares shall vest as to 100% of the shares on
the fifth anniversary of the commencement date of

                                       2.
<PAGE>   3
Executive's employment with the Company, provided Executive remains continuously
employed by the Company through that date. Prior to the fifth anniversary of
Executive's employment commencement date, the vesting of the option shares shall
accelerate as to one-half (1/2) of the option shares on the occurrence of (i) a
merger or acquisition of the Company where the value of the merger or
acquisition per share of Common Stock is more than $9.25 (as adjusted for stock
splits, stock dividends, recapitalizations and the like), or (ii) the Company
makes an initial public offering ("IPO") with a per share price to the public of
more than $9.25 (as adjusted for stock splits, stock dividends,
recapitalizations and the like). Prior to the fifth anniversary of Executive's
employment commencement date, the vesting of the option shares shall accelerate
as to an additional one-half (1/2) of the option shares if the Company's product
revenue for any fiscal year exceeds $20,000,000 for such fiscal year before
December 31, 2001. Such option will include an early exercise provision that
allows Executive to exercise the option as to vested and unvested shares,
subject to a right of repurchase with respect to unvested shares.

                      (v) The grants of options pursuant to subsections (ii),
(iii) and (iv) above shall be subject to the Company's standard form of stock
option agreement, copies of each of which are attached hereto as exhibits and
must be executed as a condition of the grant. While Executive remains employed
by the Company he shall have the right to exercise his options by delivery of a
non-recourse promissory note, provided: (i) the promissory note is secured by
property other than the shares of stock being purchased ("Other Property"), (ii)
the Other Property is not owned by the payee of the promissory note, and (ii)
the Other Property is worth as much as the principal value of the promissory
note on the date of exercise. As an alternative to a non-recourse promissory
note, Executive shall have the right to exercise his options while he remains
employed by the Company by delivering a full recourse promissory note secured by
a pledge of the shares purchased thereunder. If required under the laws of the
Company's state of incorporation, Executive shall pay cash for the par value of
the exercised option shares. Interest on the promissory note shall be repayable
annually at the applicable Federal rate under the Internal Revenue Code to avoid
imputed income and the principal balance and interest shall be due in full on
the earlier of the fourth anniversary of Executive's hire date, 90 days after
the Executive's termination of employment, or the one year anniversary of the
Company's initial public offering. The note shall be subject to such other terms
and conditions as may be agreed to by the Company and Executive. The credit
extended to Executive hereunder shall equal the aggregate option price payable
for the purchased shares. For 90 days following the effective date of the
termination of his employment for any reason, Executive shall have the right to
exercise his vested stock options.

                      (vi) If the Company terminates Executive's Employment
Without Cause (as defined in section 6(d)) within one year after a Change of
Control or Executive resigns for Good Reason within one year after a Change of
Control, then each of Executive's outstanding options will become fully vested.
"Change of Control" shall mean (i) a merger or consolidation in which securities
possessing more than fifty percent (50%) of the total combined voting power of
the Corporation's outstanding securities are transferred to a person or persons
different from the persons holding those securities immediately prior to such
transaction, or (ii) the sale, transfer or other disposition of all or
substantially all of the Corporation's assets in complete liquidation or
dissolution of the Corporation. "Good Reason" for Executive's resignation will
exist if he resigns within sixty days of any of the following: (i) any reduction
in his base salary, except as generally applicable to all executive officers;
(ii) a change in his

                                       3.
<PAGE>   4
position with the Company which materially reduces his level of responsibility;
or (iii) any requirement that he relocate his place of employment by more than
fifty (50) miles from his then current office, provided such reduction, change
or relocation is effected by the Company without his written consent.

               (d) SPECIAL BONUS. Executive will participate in a special bonus
program pursuant to which he will be paid a net cash bonus of at least $50,000
and, subject to the approval of the Board, up to $100,000 each year, which will
be grossed up for tax purposes, provided he is employed as of November 1 of such
year.

        3. VACATION AND EXECUTIVE BENEFITS. During the term of his Employment,
the Executive shall be eligible for paid vacations in accordance with the
Company's standard policy for similarly situated employees, as it may be amended
from time to time. During the term of his Employment, the Executive shall be
eligible to participate in any employee benefit plans maintained by the Company
for similarly situated employees, subject in each case to the generally
applicable terms and conditions of the plan in question and to the
determinations of any person or committee administering such plan.

        4. BUSINESS EXPENSES. During the term of his Employment, the Executive
shall be authorized to incur necessary and reasonable travel, entertainment and
other business expenses in connection with his duties hereunder. The Company
shall reimburse the Executive for such expenses upon presentation of an itemized
account and appropriate supporting documentation, all in accordance with the
Company's generally applicable policies.

        5. TERM OF EMPLOYMENT.

               (a) BASIC RULE. Executive will remain employed with the Company
from the commencement date set forth in Section 1(d) until the date when the
Executive's Employment terminates pursuant to Subsection (b) below. The
Executive's Employment with the Company shall be "at will," and either the
Executive or the Company may terminate the Executive's Employment at any time,
for any reason, with or without Cause. Any contrary representations, which may
have been made to the Executive shall be superseded by this Agreement. This
Agreement shall constitute the full and complete agreement between the Executive
and the Company on the "at will" nature of the Executive's Employment, which may
only be changed in an express written agreement signed by the Executive and a
duly authorized officer of the Company.

               (b) TERMINATION. The Company may terminate the Executive's
Employment at any time and for any reason (or no reason), and with or without
Cause, by giving the Executive notice in writing. The Executive may terminate
his Employment by giving the Company 14 days' advance notice in writing. The
Executive's Employment shall terminate automatically in the event of his death
or permanent disability.

               (c) RIGHTS UPON TERMINATION. Except as expressly provided in
Section 6, upon the termination of the Executive's Employment pursuant to this
Section 5, the Executive shall only be entitled to the compensation, benefits
and reimbursements described in Sections 2,

                                       4.
<PAGE>   5
3 and 4 for the period preceding the effective date of the termination. The
payments under this Agreement shall fully discharge all responsibilities of the
Company to the Executive.

               (d) TERMINATION AGREEMENT. This Agreement shall terminate when
all obligations of the parties hereunder have been satisfied. The termination of
this Agreement shall not limit or otherwise affect any of the Executive's
obligations under Section 7.

        6.     TERMINATION BENEFITS.

               (a) SEVERANCE PAY. If the Company terminates the Executive's
Employment for any reason other than for Cause, or if employment is terminated
by the death or permanent disability of the Executive, then the Company shall:

                      (i) pay the Executive his Base Compensation for a period
of twelve (12) months following the termination of his Employment (the
"Continuation Period"), which Base Compensation shall be paid at the rate in
effect at the time of the termination of Employment and in accordance with the
Company's standard payroll procedures, and

                      (ii) provide for vesting of the options granted pursuant
to Sections 2(c)(ii) and 2(c)(iii) in an amount equal to an additional twelve
(12) months following the termination of his Employment (if the Executive has
been continuously employed by the Company for less than two years at the time of
the termination) or provide for vesting of the options granted pursuant to
Sections 2(c)(ii), (iii) and (iv) such that they shall become fully vested (if
the Executive has been continuously employed by the Company for two years or
more at the time of the termination).

               (b) HEALTH INSURANCE. If Subsection (c) below applies, and if the
Executive elects to continue his health insurance coverage under the
Consolidated Omnibus Budget Reconciliation Act ("COBRA") following the
termination of his Employment, then the Company shall pay the Executive's
monthly premium under COBRA until the earliest of (i) the close of the
Continuation Period or (ii) the expiration of the Executive's continuation
coverage under COBRA.

               (c) GENERAL RELEASE. Any other provision of this Agreement
notwithstanding, if the Executive has been continuously employed by the Company
for two years or more at the time of his termination then Subsections (a) and
(b) above shall only apply if the Executive (i) has executed a general release
(in the form attached hereto as Exhibit A) of all known and unknown claims that
he may then have against the Company or persons affiliated with the Company and
(ii) has agreed not to prosecute any legal action or other proceeding based upon
any of such claims.

               (d) DEFINITION OF "CAUSE." For all purposes under this Agreement,
"Cause" shall mean:

                      (i) Unauthorized use or intentional disclosure of the
confidential information or trade secrets of the Company;

                                       5.
<PAGE>   6
                      (ii) Any material breach of this Agreement or the Employee
Proprietary Information Agreement between the Executive and the Company;

                      (iii) Conviction of, or a plea of "guilty" or "no contest"
to, a felony under the laws of the United States or any state thereof;

                      (iv) Misappropriation of the assets of the Company or
other acts of dishonesty;

                      (v) Engagement in substance abuse which substantially
impairs Executive's ability to perform the duties and obligations of Executive's
employment or causes material harm to the reputation of the Company;

                      (vi) Personal engagement in any act of moral turpitude
that causes material harm to the reputation of the Company;

                      (vii) Commencement of employment with another employer
while Executive is an employee of the Company without the prior consent of the
Board of Directors; or

                      (VIII) Material misconduct or gross negligence in the
performance of duties assigned to the Executive under this Agreement.

        7. NON-SOLICITATION AND NON-DISCLOSURE.

               (a) NON-SOLICITATION. During the period commencing on the date of
this Agreement and continuing until (i) the date Executive's Employment
terminates if the Company terminates Executive's Employment for any reason other
than Cause, or (ii) the first anniversary of the date Executive's Employment
terminates if Executive resigns for any reason or the Company terminates
Executive's Employment for Cause, the Executive shall not directly or
indirectly, personally or through others, solicit or attempt to solicit (on the
Executive's own behalf or on behalf of any other person or entity) the
employment of any employee of the Company or any of the Company's affiliates.

               (b) NON-DISCLOSURE. As a condition of employment the Executive
has entered into a Proprietary Information Agreement with the Company, which is
incorporated herein by reference.

        8. SUCCESSORS.

               (a) COMPANY'S SUCCESSORS. This Agreement shall be binding upon
any successor (whether direct or indirect and whether by purchase, lease,
merger, consolidation, liquidation or otherwise) to all or substantially all of
the Company's business and/or assets. For all purposes under this Agreement, the
term "Company" shall include any successor to the Company's business and/or
assets which becomes bound by this Agreement.

               (b) EXECUTIVE'S SUCCESSORS. This Agreement and all rights of the
Executive hereunder shall inure to the benefit of, and be enforceable by, the
Executive's personal or legal representatives, executors, administrators,
successors, heirs, distributees, devisees and legatees.

                                       6.
<PAGE>   7
        9. MISCELLANEOUS PROVISIONS.

               (a) NOTICE. Notices and all other communications contemplated by
this Agreement shall be in writing and shall be deemed to have been duly given
when personally delivered or when mailed by overnight courier, U.S. registered
or certified mail, return receipt requested and postage prepaid. In the case of
the Executive, mailed notices shall be addressed to him at the home address
which he most recently communicated to the Company in writing. In the case of
the Company, mailed notices shall be addressed to its corporate headquarters,
and all notices shall be directed to the attention of its Secretary.

               (b) MODIFICATIONS AND WAIVERS. No provision of this Agreement
shall be modified, waived or discharged unless the modification, waiver or
discharge is agreed to in writing and signed by the Executive and by an
authorized officer of the Company (other than the Executive), No waiver by
either party of any breach of, or of compliance with, any condition or provision
of this Agreement by the other party shall be considered a waiver of any other
condition or provision or of the same condition or provision at another time.

               (c) WHOLE AGREEMENT. No other agreements, representations or
understandings (whether oral or written) which are not expressly set forth in
this Agreement have been made or entered into by either party with respect to
the subject matter of this Agreement. This Agreement and the Proprietary
Information Agreement contain the entire understanding of the parties with
respect to the subject matter hereof.

               (d) WITHHOLDING TAXES. All payments made under this Agreement
shall be subject to reduction to reflect taxes or other charges required to be
withheld by law.

               (e) CHOICE OF LAW. The validity, interpretation, construction and
performance of this Agreement shall be governed by the laws of the State of
California (except provisions governing the choice of law).

               (f) SEVERABILITY. The invalidity or unenforceability of any
provision or provisions of this Agreement shall not affect the validity or
enforceability of any other provision hereof, which shall remain in full force
and effect.

               (g) ARBITRATION. Any controversy or claim arising out of or
relating to this Agreement or the breach thereof, or the Executive's Employment
or the termination thereof, shall be settled in South San Francisco, California,
by arbitration in accordance with the National Rules for the Resolution of
Employment Disputes of the American Arbitration Association. The decision of the
arbitrator shall be final and binding on the patties, and judgment on the award
rendered by the arbitrator may be entered in any court having jurisdiction
thereof. The arbitration will be in lieu of a jury trial and Executive and the
Company each waive their right to a jury trial. The parties hereby agree that
the arbitrator shall be empowered to enter an equitable decree mandating
specific enforcement of the terms of this Agreement. The Company and the
Executive shall share equally all fees and expenses of the arbitrator. Both
parties hereby consent to personal jurisdiction of the state and federal courts
located in the State of California for any action or proceeding arising from or
relating to this Agreement or relating to any arbitration in which the parties
are participants.

                                       7.
<PAGE>   8
               (h) NO ASSIGNMENT. This Agreement and all rights and obligations
of the Executive hereunder are personal to the Executive and may not be
transferred or assigned by the Executive at any time. The Company may assign its
rights under this Agreement to any entity that assumes the Company's obligations
hereunder in connection with any sale or transfer of all or a substantial
portion of the Company's assets to such entity.

                                       8.
<PAGE>   9
               (i) COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

        IN WITNESS WHEREOF, each of the parties has executed this Agreement, in
the case of the Company by its duly authorized officer, as of the day and year
first above written.

                                       WILLIAM D. YOUNG

                                       /s/ WILLIAM D. YOUNG
                                       -----------------------------------------
                                       VIROLOGIC, INC.

                                       By:
                                          --------------------------------------
                                       Title:
                                             -----------------------------------

                                       9.
<PAGE>   10
                          [Exhibit A - Form of Release]

                          GENERAL RELEASE OF ALL CLAIMS

        In consideration of the severance benefit to be paid to me by Virologic,
Inc. in accordance with the Employment Agreement entered into as of September
__, 1999, I hereby fully and forever release and discharge Virologic, Inc. and
its directors, officers, employees, agents, successors, predecessors,
subsidiaries, shareholders, employee benefit plans and assigns (together the
"Company"), from all claims and causes of action arising out of or relating in
any way to my employment with the Company, including the termination of my
employment.

        1. I understand and agree that this RELEASE is a full and complete
waiver of all claims, including (without limitation) claims of wrongful
discharge, breach of contract, breach of the covenant of good faith and fair
dealing, violation of public policy, defamation, personal injury or emotional
distress and claims under Title VII of the Civil Rights Act of 1964, as amended,
the Fair Labor Standards Act, the Equal Pay Act of 1963, the Americans with
Disabilities Act, the Civil Rights Act of 1866, the Age Discrimination in
Employment Act of 1967, as amended (ADEA), the California Fair Employment and
Housing Act, the Family and Medical Leave Act or any federal or state law or
regulation relating to employment or employment discrimination. I further
understand and agree that this RELEASE is a full and complete waiver of all
claims, including (without limitation) claims under the Employee Retirement
Income Security Act of 1974 (ERISA) related to severance benefits. I further
understand that by this RELEASE I agree not to assist, encourage, institute or
cause to be instituted the filing of any administrative charge or legal
proceeding against the Company relating to employment discrimination.

        2. I also hereby agree that nothing contained in this RELEASE shall
constitute or be treated as an admission of liability or wrongdoing by me or the
Company. This RELEASE does not relieve the Company of its obligations to comply
with the terms of the Employment Agreement, any stock option agreement or any
employee benefit plan or similar program in which I am a participant or eligible
for benefits.

        3. I agree to abide by Company's Proprietary Information and Inventions
Agreement that I previously executed.

        4. In addition, I hereby expressly waive any and all rights and benefits
conferred upon me by the provisions of Section 1542 of the Civil Code of the
State of California (or any analogous law of any other state), which states as
follows:

        A general release does not extend to claims which the creditor does not
know or suspect to exist in his favor at the time of executing the release,
which, if known by him, must have materially affected his settlement with the
debtor.

        5. I hereby acknowledge that I have read and understand the foregoing
RELEASE and that I sign it voluntarily and without coercion. I further
acknowledge that I was given an opportunity to consider and review this RELEASE
and to consult with an attorney of my own choosing concerning the waivers
contained in this RELEASE and that the waivers are knowing,

                                       1.
<PAGE>   11
conscious and with full appreciation that I am forever foreclosed from pursuing
any of the rights that I waived.

        6. I understand that I may have up to twenty-one (21) days after receipt
of this letter within which I may review and consider, discuss with an attorney
of my own choosing, and decide to execute or not execute it. I also understand
for a period of seven (7) days after I sign this RELEASE, I may revoke this
RELEASE and that the RELEASE will not become effective until seven (7) days
after I sign it, and only then if I do not revoke it. In order to revoke this
agreement, I must deliver to the Chairman of the Board of Virologic, Inc. within
seven (7) days after I have executed this RELEASE, a letter stating that I am
revoking it.

        7. I understand that if I choose to revoke this RELEASE within seven (7)
days after I signed it, I will not receive any severance benefit and the RELEASE
will have no effect.

        8. Before signing my name to this RELEASE, I state that:

        [ ] I have read it,

        [ ] I understand it,

        [ ] I know that I am giving up important rights,

        [ ] I am aware of my right to consult an attorney before signing it, and

        [ ] I have signed it knowingly and voluntarily.

Dated:
      ---------------------------      -----------------------------------------
                                       Signature

                                       -----------------------------------------
                                       Print Full Name

                                       2.

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