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                                                                  Exhibit 10.81

                                 PROMISSORY NOTE

US $2,640,752.50                                               January 16, 2001

        FOR VALUE RECEIVED, the undersigned hereby unconditionally promises to
pay to the order of EPIMMUNE INC. (the "Company"), with its principal place of
business at 5820 Nancy Ridge Drive, San Diego, California 92121, or at such
other place as the holder hereof may designate in writing, in lawful money of
the United States of America and in immediately available funds, the principal
sum of two million six hundred forty thousand seven hundred fifty-two dollars
and fifty cents (US $2,640,752.50) together with interest accrued from the date
hereof on the unpaid principal at the rate of 5.61% per annum, compounded
annually, or the maximum rate permissible by law (which under the laws of the
State of California shall be deemed to be the laws relating to permissible rates
of interest on commercial loans), whichever is less, as follows:

        PRINCIPAL AND INTEREST REPAYMENT. The outstanding principal amount
hereunder, together with accrued and unpaid interest thereon calculated on the
basis of a 360-day year for the actual number of days elapsed, shall be due and
payable in full on January 16, 2005, four (4) years from the date of this
promissory note (the "Note");

provided, however, that in the event that the undersigned's Continuous Service
(as defined in that certain Restricted Stock Purchase Agreement between the
undersigned and the Company of even date herewith) with the Company is
terminated for any reason prior to payment in full of this Note, then this Note
shall be accelerated and all remaining unpaid principal and interest shall
become due and payable immediately after such termination.

        If the undersigned fails to pay any of the principal and accrued
interest when due, the Company, at its sole option, shall have the right to
accelerate this Note, in which event the entire principal balance and all
accrued interest shall become immediately due and payable, and immediately
collectible by the Company pursuant to applicable law and the terms of this
note.

        This Note may be prepaid without penalty. All money paid toward the
satisfaction of this Note shall be applied first to the payment of interest as
required hereunder and then to the retirement of the principal.

        The full amount of this Note is secured by a pledge of shares of the
Company, and is subject to all of the terms and provisions of the Restricted
Stock Purchase Agreement and the Stock Pledge Agreement, each of even date
herewith between the undersigned and the Company. With respect to each
indivisible share of Company stock purchased with the proceeds of this Note, the
undersigned shall be personally liable for repayment of fifty percent (50%) of
the amounts due under this Note, and shall not be personally liable for
repayment of the remaining fifty percent (50%) of the amounts due under this
Note.

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        The undersigned hereby represents and agrees that the amounts due under
this Note are not consumer debt, and are not incurred primarily for personal,
family or household purposes, but are for business and commercial purposes only.

        The undersigned hereby waives presentment, protest and notice of
protest, demand for payment, notice of dishonor and all other notices or demands
in connection with the delivery, acceptance, performance, default or endorsement
of this Note.

        The holder hereof shall be entitled to recover, and the undersigned
agrees to pay when incurred, all costs and expenses of collection of this Note,
including without limitation, reasonable attorneys' fees.

        This Note shall be governed by, and construed, enforced and interpreted
in accordance with, the laws of the State of California, excluding conflict of
laws principles that would cause the application of laws of any other
jurisdiction.

                                            Signed  /s/ Emile Loria
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                                                    EMILE LORIA

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                                                                  Exhibit 10.82

                             STOCK PLEDGE AGREEMENT

        THIS STOCK PLEDGE AGREEMENT ("Pledge Agreement") is made by EMILE LORIA,
an individual with a residence at 31 rue du Dr Jean Arlaud, 31500 Toulouse,
France ("Pledgor"), in favor of EPIMMUNE INC., a Delaware corporation with its
principal place of business at 5820 Nancy Ridge Drive, San Diego, California
92121 ("Pledgee").

        WHEREAS, Pledgor has concurrently herewith executed that certain
Promissory Note (the "Note") in favor of Pledgee in the amount of two million
six hundred forty thousand seven hundred fifty-two dollars and fifty cents (US
$2,640,752.50) in payment of the purchase price of one million fifty-six
thousand three hundred one (1,056,301) shares of the Common Stock of Pledgee;
and

        WHEREAS, Pledgee is willing to accept the Note from Pledgor, but only
upon the condition, among others, that Pledgor shall have executed and delivered
to Pledgee this Pledge Agreement and the Collateral (as defined below):

        NOW, THEREFORE, in consideration of the foregoing recitals and for other
good and valuable consideration, the receipt and adequacy of which are hereby
acknowledged, and intending to be legally bound, Pledgor hereby agrees as
follows:

        1. As security for the full, prompt and complete payment and performance
when due (whether by stated maturity, by acceleration or otherwise) of all
indebtedness of Pledgor to Pledgee created under the Note (all such indebtedness
being the "Liabilities"), together with, without limitation, the prompt payment
of all expenses, including, without limitation, reasonable attorneys' fees and
legal expenses, incidental to the collection of the Liabilities and the
enforcement or protection of Pledgee's lien in and to the collateral pledged
hereunder, Pledgor hereby pledges to Pledgee, and grants to Pledgee, a first
priority security interest in all of the following (collectively, the
"Collateral"):

           (a) one million fifty-six thousand three hundred one (1,056,301)
shares of Common Stock of Pledgee represented by certificate numbered
___________________ (the "Pledged Shares"), and all dividends, cash,
instruments, and other property or proceeds from time to time received,
receivable, or otherwise distributed in respect of or in exchange for any or all
of the Pledged Shares; and

           (b) all voting trust certificates held by Pledgor evidencing the
right to vote any Pledged Shares subject to any voting trust.

           The term "indebtedness" is used herein in its most comprehensive
sense and includes any and all advances, debts, obligations and Liabilities
heretofore, now or hereafter made, incurred or created, whether voluntary or
involuntary and whether due or not due, absolute or contingent, liquidated or
unliquidated, determined or undetermined, and whether recovery upon such
indebtedness may be or hereafter becomes unenforceable.

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        2. At any time, without notice, and at the expense of Pledgor, Pledgee
in its name or in the name of its nominee or of Pledgor may, but shall not be
obligated to: (1) collect by legal proceedings or otherwise all dividends
(except cash dividends other than liquidating dividends), interest, principal
payments and other sums now or hereafter payable upon or on account of said
Collateral; (2) enter into any extension, reorganization, deposit, merger or
consolidation agreement, or any agreement in any way relating to or affecting
the Collateral, and in connection therewith may deposit or surrender control of
such Collateral thereunder, accept other property in exchange for such
Collateral and do and perform such acts and things as it may deem proper, and
any money or property received in exchange for such Collateral shall be applied
to the indebtedness or thereafter held by it pursuant to the provisions hereof;
(3) insure, process and preserve the Collateral; (4) cause the Collateral to be
transferred to its name or to the name of its nominee; (5) exercise as to such
Collateral all the rights, powers and remedies of an owner, except that so long
as no default exists under the Note or hereunder Pledgor shall retain all voting
rights as to the Pledged Shares.

        3. Pledgor agrees to pay prior to delinquency all taxes, charges, liens
and assessments against the Collateral, and upon the failure of Pledgor to do
so, Pledgee at its option may pay any of them and shall be the sole judge of the
legality or validity thereof and the amount necessary to discharge the same.

        4. At the option of Pledgee and without necessity of demand or notice,
all or any part of the indebtedness of Pledgor shall immediately become due and
payable irrespective of any agreed maturity, upon the happening of any of the
following events: (1) failure to keep or perform any of the terms or provisions
of this Pledge Agreement; (2) failure to pay any installment of principal or
interest on the Note when due; (3) the levy of any attachment, execution or
other process against the Collateral; or (4) the insolvency, commission of an
act of bankruptcy, general assignment for the benefit of creditors, filing of
any petition in bankruptcy or for relief under the provisions of Title 11 of the
United States Code of, by, or against Pledgor.

        5. In the event of the nonpayment of any indebtedness when due, whether
by acceleration or otherwise, or upon the happening of any of the events
specified in the last preceding paragraph, Pledgee may then, or at any time
thereafter, at its election, apply, set off, collect or sell in one or more
sales, or take such steps as may be necessary to liquidate and reduce to cash in
the hands of Pledgee in whole or in part, with or without any previous demands
or demand of performance or notice or advertisement, the whole or any part of
the Collateral in such order as Pledgee may elect, and any such sale may be made
either at public or private sale at its place of business or elsewhere, or at
any broker's board or securities exchange, either for cash or upon credit or for
future delivery; provided, however, that if such disposition is at private sale,
then the purchase price of the Collateral shall be equal to the public market
price then in effect, or, if at the time of sale no public market for the
Collateral exists, then, in recognition of the fact that the sale of the
Collateral would have to be registered under the Securities Act of 1933 and that
the expenses of such registration are commercially unreasonable for the type and
amount of collateral pledged hereunder, Pledgee and Pledgor hereby agree that
such private sale shall be at a purchase price mutually agreed to by Pledgee and
Pledgor or, if the parties cannot agree upon a purchase price, then at a
purchase price established by a majority of three independent appraisers
knowledgeable of the value of such collateral, one named by Pledgor within ten
(10) days after written request by the Pledgee to do so, one named by Pledgee
within such ten (10) day period,

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and the third named by the two appraisers so selected, with the appraisal to be
rendered by such body within thirty (30) days of the appointment of the third
appraiser. The cost of such appraisal, including all appraiser's fees, shall be
charged against the proceeds of sale as an expense of such sale. Pledgee may be
the purchaser of any or all Collateral so sold and hold the same thereafter in
its own right free from any claim of Pledgor or right of redemption. Demands of
performance, notices of sale, advertisements and presence of property at sale
are hereby waived, and Pledgee is hereby authorized to sell hereunder any
evidence of debt pledged to it. Any sale hereunder may be conducted by any
officer or agent of Pledgee.

        6. The proceeds of the sale of any of the Collateral and all sums
received or collected by Pledgee from or on account of such Collateral shall be
applied by Pledgee to the payment of expenses incurred or paid by Pledgee in
connection with any sale, transfer or delivery of the Collateral, to the payment
of any other costs, charges, attorneys' fees or expenses mentioned herein, and
to the payment of the indebtedness or any part hereof, all in such order and
manner as Pledgee in its discretion may determine. Pledgee shall then pay any
balance to Pledgor.

        7. Upon the transfer of all or any part of the indebtedness Pledgee may
transfer all or any part of the Collateral and shall be fully discharged
thereafter from all liability and responsibility with respect to such Collateral
so transferred, and the transferee shall be vested with all the rights and
powers of Pledgee hereunder with respect to such Collateral so transferred; but
with respect to any Collateral not so transferred Pledgee shall retain all
rights and powers hereby given.

        8. Until all indebtedness shall have been paid in full, the power of
sale and all other rights, powers and remedies granted to Pledgee hereunder
shall continue to exist and may be exercised by Pledgee at any time and from
time to time irrespective of the fact that the indebtedness or any part thereof
may have become barred by any statute of limitations, or that the personal
liability of Pledgor may have ceased.

        9. Pledgee agrees that so long as no default exists under the Note or
hereunder, the Pledged Shares shall, upon the request of Pledgor, be released
from pledge as the indebtedness is paid. Such releases shall be at the rate of
one (1) share for each two dollars and fifty cents (US $2.50) of principal
amount of indebtedness paid, as adjusted for any stock split, stock dividend,
recapitalization, combination, reorganization, reclassification or similar event
involving a change in the capital structure of the Company. Release from pledge,
however, shall not result in release from the provisions of those certain Joint
Escrow Instructions, if any, of even date herewith among the parties to this
Pledge Agreement and the Escrow Agent named therein, except as permitted by the
terms of such Joint Escrow Instructions.

        10. Pledgee may at any time deliver the Collateral or any part thereof
to Pledgor and the receipt of Pledgor shall be a complete and full acquittance
for the Collateral so delivered, and Pledgee shall thereafter be discharged from
any liability or responsibility herefore.

        11. The rights, powers and remedies given to Pledgee by this Pledge
Agreement shall be in addition to all rights, powers and remedies given to
Pledgee by virtue of any statute or rule of law. Any forbearance or failure or
delay by Pledgee in exercising any right, power or remedy hereunder shall not be
deemed to be a waiver of such right, power or remedy, and any single or

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partial exercise of any right, power or remedy hereunder shall not preclude the
further exercise thereof; and every right, power and remedy of Pledgee shall
continue in full force and effect until such right, power or remedy is
specifically waived by an instrument in writing executed by Pledgee.

        12. If any provision of this Pledge Agreement is held to be
unenforceable for any reason, it shall be adjusted, if possible, rather than
voided in order to achieve the intent of the parties to the extent possible. In
any event, all other provisions of this Pledge Agreement shall be deemed valid
and enforceable to the full extent possible.

        13. This Pledge Agreement shall be governed by, and construed in
accordance with, the laws of the State of California as applied to contracts
made and performed entirely within the State of California by residents of such
State.

        Dated: January 16, 2001

                                                     /s/ Emile Loria
                                                     -------------------------
                                                     EMILE LORIA

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