<PAGE>   1
                                                                    EXHIBIT 4.31

                                 CLASS B WARRANT


THE SECURITIES REPRESENTED BY THIS WARRANT HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS. THE
SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE OFFERED FOR SALE,
SOLD, TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR
APPLICABLE STATE SECURITIES LAWS, OR AN OPINION OF COUNSEL IN A FORM REASONABLY
SATISFACTORY TO THE ISSUER THAT REGISTRATION IS NOT REQUIRED UNDER SAID ACT OR
APPLICABLE STATE SECURITIES LAWS OR UNLESS SOLD PURSUANT TO RULE 144 UNDER SAID
ACT. NOTWITHSTANDING THE FOREGOING, THIS WARRANT MAY BE PLEDGED IN CONNECTION
WITH A BONA FIDE MARGIN ACCOUNT.

                          ADVANCED VIRAL RESEARCH CORP.

                        WARRANT TO PURCHASE COMMON STOCK

Warrant No.:  WB-1                                   Number of Shares: 1,000,000
Date of Issuance: February 9, 2001


Advanced Viral Research Corp., a Delaware corporation (the "COMPANY"), hereby
certifies that, for Ten United States Dollars ($10.00) and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, MARK ANGELO, the registered holder hereof or its permitted
assigns, is entitled, subject to the terms set forth below, to purchase from the
Company upon surrender of this Warrant, at any time or times on or after the
date hereof, but not after 11:59 P.M. Eastern Time on the Expiration Date (as
defined herein) One Million (1,000,000) fully paid and nonassessable shares of
Common Stock (as defined herein) of the Company (the "WARRANT SHARES") at the
Warrant Exercise Price per share provided in Section 1(b) below; provided,
however, that in no event shall the holder be entitled to exercise this Warrant
for a number of Warrant Shares in excess of that number of Warrant Shares which,
upon giving effect to such exercise, would cause the aggregate number of shares
of Common Stock beneficially owned by the holder and its affiliates to exceed
4.99% of the outstanding shares of the Common Stock following such exercise,
except within 60 days of the Expiration Date. For purposes of the foregoing
proviso, the aggregate number of shares of Common Stock beneficially owned by
the holder and its affiliates shall include the number of shares of Common Stock
issuable upon exercise of this Warrant with respect to which the determination
of such proviso is being made, but shall exclude shares of Common Stock which
would be issuable upon (i) exercise of the


                                      -1-


<PAGE>   2

remaining, unexercised Warrants beneficially owned by the holder and its
affiliates and (ii) exercise or conversion of the unexercised or unconverted
portion of any other securities of the Company beneficially owned by the holder
and its affiliates (including, without limitation, any convertible notes or
preferred stock) subject to a limitation on conversion or exercise analogous to
the limitation contained herein. Except as set forth in the preceding sentence,
for purposes of this paragraph, beneficial ownership shall be calculated in
accordance with Section 13(d) of the Securities Exchange Act of 1934, as
amended. For purposes of this Warrant, in determining the number of outstanding
shares of Common Stock a holder may rely on the number of outstanding shares of
Common Stock as reflected in (1) the Company's most recent Form 10-Q or Form
10-K, as the case may be, (2) a more recent public announcement by the Company
or (3) any other notice by the Company or its transfer agent setting forth the
number of shares of Common Stock outstanding. Upon the written request of any
holder, the Company shall promptly, but in no event later than one (1) Business
Day following the receipt of such notice, confirm in writing to any such holder
the number of shares of Common Stock then outstanding. In any case, the number
of outstanding shares of Common Stock shall be determined after giving effect to
the exercise of Warrants (as defined below) by such holder and its affiliates
since the date as of which such number of outstanding shares of Common Stock was
reported.

         Section 1.

                  (a)      Placement Agent Agreement. This Warrant is one of the
common stock purchase warrants (the "WARRANTS") issued pursuant to the Placement
Agent Agreement dated as of February 9, 2001 between the Company and May Davis
Group, Inc. (the "PLACEMENT AGENT AGREEMENT").

                  (b)      Definitions. The following words and terms as used in
this Warrant shall have the following meanings:

                           (i)      "ADVANCE" means the amount of funds payable
by the Investor to the Company on any Advance Date for the purchase of Common
Stock pursuant to the Credit Agreement.

                           (ii)     "ADVANCE DATE" means each date on which the
Investor makes payment of an Advance to the Company pursuant to the Credit
Agreement.

                           (iii)    "ADVANCE NOTICE DATE" means each date on
which the Company delivers to the Investor a notice requiring the Investor to
make payment of an Advance to the Company pursuant to the Credit Agreement.

                           (iv)     "APPROVED STOCK PLAN") means any employee
benefit plan which has been approved by the Board of Directors of the Company,
pursuant to which the


                                      -2-
<PAGE>   3

Company's securities may be issued to any employee, officer or director for
services provided to the Company.

                           (v)      "BUSINESS DAY" means any day other than
Saturday, Sunday or other day on which commercial banks in the City of New York
are authorized or required by law to remain closed.

                           (vi)     "CLOSING BID PRICE" means the closing bid
price of Common Stock as quoted on the Principal Market (as reported by
Bloomberg Financial Markets ("BLOOMBERG") through its "Volume at Price"
function).

                           (vii)    "COMMON STOCK" means (i) the Company's
common stock, par value $0.01 per share, and (ii) any capital stock into which
such Common Stock shall have been changed or any capital stock resulting from a
reclassification of such Common Stock.

                           (viii)   "CREDIT AGREEMENT" means the Equity Line of
Credit Agreement dated as of February 9, 2001 between the Company and the
Investor named therein for the purchase of Common Stock by the Investor.

                           (ix)     "EXCLUDED SECURITIES" means, provided such
security is issued at a price which is greater than or equal to the arithmetic
average of the Closing Bid Prices of the Common Stock for the ten (10)
consecutive trading days immediately preceding the date of issuance, any of the
following: (a) any issuance by the Company of securities in connection with a
strategic partnership or a joint venture (the primary purpose of which is not to
raise equity capital), (b) any issuance by the Company of securities as
consideration for a merger or consolidation or the acquisition of a business,
product, license, or other assets of another person or entity, (c) the
securities described in Schedule 1(a)(ix) of this Warrant and (d) options to
purchase shares of Common Stock, provided (I) such options are issued after the
date of this Warrant to employees of the Company within 30 days of such
employee's starting his employment with the Company, and (II) the exercise price
of such options is not less than the CLOSING BID PRICE of the Common Stock on
the date of issuance of such option.

                           (x)      "EXPIRATION DATE" means the date five (5)
years from the Issuance Date of this Warrant or, if such date falls on a
Saturday, Sunday or other day on which banks are required or authorized to be
closed in the City of New York or the State of New York or on which trading does
not take place on the Principal Exchange or automated quotation system on which
the Common Stock is traded (a "HOLIDAY"), the next date that is not a Holiday.

                           (xi)     "FORCED CONVERSION" means the Company may
redeem the Warrants at a redemption price of $.01 per share provided that the
Bid Price for the Common Stock equals at least $4.00 per share for a period of
ten (10) consecutive Trading Days.


                           (xii)    "ISSUANCE DATE" means the date hereof.


                                      -3-

<PAGE>   4

                           (xiii)   "OPTIONS" means any rights, warrants or
options to subscribe for or purchase Common Stock or Convertible Securities.

                           (xiv)    "OTHER SECURITIES" means (i) those options
and warrants of the Company issued prior to, and outstanding on, the Issuance
Date of this Warrant, (ii) the shares of Common Stock issuable on exercise of
such options and warrants, provided such options and warrants are not amended
after the Issuance Date of this Warrant and (iii) the shares of Common Stock
issuabale upon exercise of this Warrants.

                           (xv)     "PERSON" means an individual, a limited
liability company, a partnership, a joint venture, a corporation, a trust, an
unincorporated organization and a government or any department or agency
thereof.

                           (xvi)    "PRINCIPAL MARKET" means the New York Stock
Exchange, the American Stock Exchange, the Nasdaq National Market, the Nasdaq
SmallCap Market, whichever is at the time the principal trading exchange or
market for such security, or the over-the-counter market on the electronic
bulletin board for such security as reported by BLOOMBERG or, if no bid or sale
information is reported for such security by BLOOMBERG, then the average of the
bid prices of each of the market makers for such security as reported in the
"pink sheets" by the National Quotation Bureau, Inc.

                           (xvii)   "REGISTRATION RIGHTS AGREEMENT" means the
Registration Rights Agreement dated as of Class B Warrants February 9, 2001
between the Company and the holders of the with respect to the registration
rights pertaining to the Common Stock issuable upon exercise of this Warrant.

                           (xviii)  "SECURITIES ACT" means the Securities Act of
1933, as amended.

                           (xix)    "WARRANT" means this Warrant and all
Warrants issued in exchange, transfer or replacement thereof.

                           (xx)     "WARRANT EXERCISE PRICE" shall be equal to
110% of the Closing Bid Price of the Common Stock on any Advance Notice Date
with respect to that number of Warrant Shares the holder is entitled to purchase
on or after the Advance Date specified in the Advance Notice Date, as determined
pursuant to Section 2(b) below or $1.00, whichever is higher.

                           (xxi)    "WARRANT SHARES" means the shares of Common
Stock issuable at any time upon exercise of this Warrant.

                  (c)      Other Definitional Provisions.

                           (i)      Except as otherwise specified herein, all
references herein (A) to the Company shall be deemed to include the Company's
successors and (B) to any applicable law defined or referred to herein shall be
deemed references to such applicable law as the same may have been or may be
amended or supplemented from time to time.


                                      -4-

<PAGE>   5

                           (ii)     When used in this Warrant, the words
"HEREIN", "HEREOF"(pound) and "HEREUNDER"(pound) and words of similar import,
shall refer to this Warrant as a whole and not to any provision of this Warrant,
and the words "SECTION"(pound) "SCHEDULE"(pound) and "EXHIBIT" shall refer to
Sections of, and Schedules and EXhibits to, this Warrant unless otherwise
specified.

                           (iii)    Whenever the context so requires, the neuter
gender includes the masculine or feminine, and the singular number includes the
plural, and vice versa.

         Section  2.       Exercise of Warrant.

                  (a)      Subject to the terms and conditions hereof, this
Warrant may be exercised by the holder hereof then registered on the books of
the Company, pro rata as hereinafter provided, at any time on any Business Day
on or after the opening of business on such Business Day, commencing with the
first Advance Date, and prior to 11:59 P.M. Eastern Time on the Expiration Date,
by (i) delivery of a written notice, in the form of the subscription notice
attached as Exhibit A hereto (the "EXERCISE NOTICE"), of such holder's election
to exercise this Warrant, which notice shall specify the number of Warrant
Shares to be purchased, (ii) (A) payment to the Company of an amount equal to
the Warrant Exercise Price(s) applicable to the Warrant Shares being purchased,
multiplied by the number of Warrant Shares (at the applicable Warrant Exercise
Price) as to which this Warrant is being exercised (plus any applicable issue or
transfer taxes) (the "AGGREGATE EXERCISE PRICE") in cash or wire transfer of
immediately available funds or (B) notification to the Company that this Warrant
is being exercised pursuant to a Cashless Exercise (as defined in Section 2(f))
and (iii) the surrender of this Warrant (or an indemnification undertaking with
respect to this Warrant in the case of its loss, theft or destruction) to a
common carrier for overnight delivery to the Company as soon as practicable
following such date. In the event of any exercise of the rights represented by
this Warrant in compliance with this Section 2(a), the Company shall on the
second Business Day following the date of receipt of the Exercise Notice, the
Aggregate Exercise Price (or notice of a Cashless Exercise) and this Warrant (or
an indemnification undertaking with respect to this Warrant in the case of its
loss, theft or destruction) (the "EXERCISE DELIVERY DOCUMENTS"), credit such
aggregate number of shares of Common Stock to which the holder shall be entitled
to the holder's or its designee's balance account with The Depository Trust
Company; provided, however, if the holder who submitted the Exercise Notice
requested physical delivery of any or all of the Warrant Shares, then the
Company shall, on or before the second Business Day following receipt of the
Exercise Delivery Documents, issue and surrender to a common carrier for
overnight delivery to the address specified in the Exercise Notice, a
certificate, registered in the name of the holder, for the number of shares of
Common Stock to which the holder shall be entitled pursuant to such request.
Upon delivery of the Exercise Notice and Aggregate Exercise Price referred to in
clause (ii)(A) above or notification to the Company of a Cashless Exercise
referred to in Section 2(e), the holder of this Warrant shall be deemed for all
corporate purposes to have become the holder of record of the Warrant Shares
with respect to which this Warrant has been exercised, irrespective of the date
of delivery of this Warrant as required by clause (iii) above or the
certificates evidencing such Warrant Shares. In the case of a dispute as to the
determination of the Warrant Exercise Price, the Closing Bid Price or the
arithmetic


                                      -5-


<PAGE>   6

calculation of the Warrant Shares, the Company shall promptly issue to the
holder the number of Warrant Shares that is not disputed and shall submit the
disputed determinations or arithmetic calculations to the holder via facsimile
within one (1) Business Day of receipt of the holder's Exercise Notice. If the
holder and the Company are unable to agree upon the determination of the Warrant
Exercise Price or arithmetic calculation of the Warrant Shares within one (1)
day of such disputed determination or arithmetic calculation being submitted to
the holder, then the Company shall immediately submit via facsimile (i) the
disputed determination of the Warrant Exercise Price or the Closing Bid Price to
an independent, reputable investment banking firm or (ii) the disputed
arithmetic calculation of the Warrant Shares to its independent, outside
accountant The Company shall cause the investment banking firm or the
accountant, as the case may be, to perform the determinations or calculations
and notify the Company and the holder of the results no later than forty-eight
(48) hours from the time it receives the disputed determinations or
calculations. Such investment banking firm's or accountant's determination or
calculation, as the case may be, shall be deemed conclusive absent manifest
error.

                  (b)      This Warrant shall be exercisable pro rata on or
after each Advance Date with respect to that number of Warrant Shares equal to
the product obtained by multiplying 5,000,000 by a fraction, the numerator of
which is the amount of the Advance payable on the applicable Advance Date and
the denominator of which is $20,000,000. Warrant Shares which become eligible
for purchase on any Advance Date with respect to which this Warrant remains
unexercised may be purchased on any subsequent Business Day for the applicable
Warrant Exercise Price in accordance with the provisions of Section 2(a).

                  (c)      Unless the rights represented by this Warrant shall
have expired or shall have been fully exercised, the Company shall, as soon as
practicable and in no event later than five (5) Business Days after any exercise
and at its own expense, issue a new Warrant identical in all respects to this
Warrant exercised except it shall represent rights to purchase the number of
Warrant Shares purchasable immediately prior to such exercise under this Warrant
exercised, less the number of Warrant Shares with respect to which such Warrant
is exercised. The holder shall have the right to exchange this Warrant for a new
warrant or warrants, at any time, such that one warrant represents the portion
of this Warrant that is present exercisable and the other warrant represents the
unexercisable portion of this Warrant as described in Section 2(b).

                  (d)      No fractional Warrant Shares are to be issued upon
any pro rata exercise of this Warrant, but rather the number of Warrant Shares
issued upon such exercise of this Warrant shall be rounded up or down to the
nearest whole number.

                  (e)      If the Company shall fail for any reason or for no
reason to issue to the holder within three (3) Business Days of receipt of the
Exercise Delivery Documents, a certificate for the number of Warrant Shares to
which the holder is entitled or to credit the holder's balance account with The
Depository Trust Company for such number of Warrant Shares to which the holder
is entitled upon the holder's exercise of this Warrant, the Company shall, in
addition to any other remedies under this Warrant or the Placement Agent
Agreement


                                      -6-
<PAGE>   7

or otherwise available to such holder, pay as additional damages in cash to such
holder on each day the issuance of such certificate for Warrant Shares is not
timely effected an amount equal to 0.5% of the product of (A) the sum of the
number of Warrant Shares not issued to the holder on a timely basis and to which
the holder is entitled, and (B) the Closing Bid Price of the Common Stock for
the trading day immediately preceding the last possible date which the Company
could have issued such Common Stock to the holder without violating this Section
2.

                  (f)      If within seven (7) Business Days after the Company's
receipt of the Exercise Delivery Documents, the Company fails to deliver a new
Warrant to the holder for the number of Warrant Shares to which such holder is
entitled pursuant to Sections 2(b) and 2(c) hereof, then, in addition to any
other available remedies under this Warrant or the Placement Agent Agreement, or
otherwise available to such holder, the Company shall pay as additional damages
in cash to such holder on each day after such seventh (7th) Business Day that
such delivery of such new Warrant is not timely effected in an amount equal to
0.5% of the product of (A) the number of Warrant Shares represented by the
portion of this Warrant which is not being exercised and (B) the Closing Bid
Price of the Common Stock for the trading day immediately preceding the last
possible date which the Company could have issued such Warrant to the holder
without violating this Section 2.

                  (g)      If the Warrant Shares are not covered by an effective
registration statement for the resale of the Warrant Shares, the holder of this
Warrant may, commencing six months from the date hereof, at its election
exercised in its sole discretion, exercise this Warrant to the extent then
exercisable, in lieu of making payment of the Aggregate Exercise Price in cash,
elect instead to receive upon such exercise the "Net Number" of shares of Common
Stock determined according to the following formula (a "CASHLESS EXERCISE"):

          Net Number = (A x B) - (A x C)
                       -----------------
                               B
                   For purposes of the foregoing formula:

                           A = the total number of Warrant Shares with
                           respect to which this Warrant is then being
                           exercised.

                           B = the Closing Bid Price of the Common Stock on
                           the date of exercise of the Warrant.

                           C = the Warrant Exercise Price then in effect
                           for the applicable Warrant Shares at the time of such
                           exercise.

         For purposes of this paragraph 2(g), each portion of this Warrant on
any Advance Date shall be treated as a separate Warrant.


                                      -7-
<PAGE>   8

         Section 3.        Covenants as to Common Stock. The Company hereby
covenants and agrees as follows:

                  (a)      This Warrant is, and any Warrants issued in
substitution for or replacement of this Warrant will upon issuance be, duly
authorized and validly issued.

                  (b)      All Warrant Shares which may be issued upon the
exercise of the rights represented by this Warrant will, upon issuance, be
validly issued, fully paid and nonassessable and free from all taxes, liens and
charges with respect to the issue thereof.

                  (c)      During the period within which the rights represented
by this Warrant may be exercised, the Company will at all times have authorized
and reserved at least 100% of the number of shares of Common Stock needed to
provide for the exercise of the rights then represented by this Warrant and the
par value of said shares will at all times be less than or equal to the
applicable Warrant Exercise Price.

                  (d)      The Company shall promptly file a registration
statement with the Securities and Exchange Commission to secure the listing of
the Warrant Shares on the Principal Market in accordance with the terms and
conditions regarding the registration rights of holders of Warrants set forth in
the Registration Rights Agreement and shall maintain, so long as any other
shares of Common Stock shall be so listed, such listing of all Warrant Shares
from time to time issuable upon the exercise of this Warrant; and the Company
shall so list on each national securities exchange or automated quotation
system, as the case may be, and shall maintain such listing of, any other shares
of capital stock of the Company issuable upon the exercise of this Warrant if
and so long as any shares of the same class shall be listed on such national
securities exchange or automated quotation system.

                  (e)      The Company will not, by amendment of its Certificate
of Incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities, or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms to be observed or performed by it hereunder, but will at all times in
good faith assist in the carrying out of all the provisions of this Warrant and
in the taking of all such action as may reasonably be requested by the holder of
this Warrant in order to protect the exercise privilege of the holder of this
Warrant against dilution or other impairment, consistent with the tenor and
purpose of this Warrant. The Company will not increase the par value of any
shares of Common Stock receivable upon the exercise of this Warrant above the
Warrant Exercise Price then in effect, and (ii) will take all such actions as
may be necessary or appropriate in order that the Company may validly and
legally issue fully paid and nonassessable shares of Common Stock upon the
exercise of this Warrant.

                  (f)      This Warrant will be binding upon any entity
succeeding to the Company by merger, consolidation or acquisition of all or
substantially all of the Company's assets.

         Section 4.        Taxes. The Company shall pay any and all taxes which
may be payable with respect to the issuance and delivery of Warrant Shares upon
exercise of this Warrant.


                                      -8-
<PAGE>   9

         Section 5.        Warrant Holder Not Deemed a Stockholder. Except as
otherwise specifically provided herein, no holder, as such, of this Warrant
shall be entitled to vote or receive dividends or be deemed the holder of shares
of the Company for any purpose, nor shall anything contained in this Warrant be
construed to confer upon the holder hereof, as such, any of the rights of a
stockholder of the Company or any right to vote, give or withhold consent to any
corporate action (whether any reorganization, issue of stock, reclassification
of stock, consolidation, merger, conveyance or otherwise), receive notice of
meetings, receive dividends or subscription rights, or otherwise, prior to the
issuance to the holder of this Warrant of the Warrant Shares which he or she is
then entitled to receive upon the due exercise of this Warrant. In addition,
nothing contained in this Warrant shall be construed as imposing any liabilities
on such holder to purchase any securities (upon exercise of this Warrant or
otherwise) or as a stockholder of the Company, whether such liabilities are
asserted by the Company or by creditors of the Company. Notwithstanding this
Section 5, the Company will provide the holder of this Warrant with copies of
the same notices and other information given to the stockholders of the Company
generally, contemporaneously with the giving thereof to the stockholders.

         Section 6.        Representations of Holder. The holder of this
Warrant, by the acceptance hereof, represents that it is acquiring this Warrant
and the Warrant Shares for its own account for investment only and not with a
view towards, or for resale in connection with, the public sale or distribution
of this Warrant or the Warrant Shares, except pursuant to sales registered or
exempted under the Securities Act; provided, however, that by making the
representations herein, the holder does not agree to hold this Warrant or any of
the Warrant Shares for any minimum or other specific term and reserves the right
to dispose of this Warrant and the Warrant Shares at any time in accordance with
or pursuant to a registration statement or an exemption under the Securities
Act. The holder of this Warrant further represents, by acceptance hereof, that,
as of this date, such holder is an "accredited investor" as such term is defined
in Rule 501(a)(1) of Regulation D promulgated by the Securities and Exchange
Commission under the Securities Act (an "ACCREDITED INVESTOR"). Upon exercise of
this Warrant, other than pursuant to a Cashless Exercise, the holder shall, if
requested by the Company, confirm in writing, in a form satisfactory to the
Company, that the Warrant Shares so purchased are being acquired solely for the
holder's own account and not as a nominee for any other party, for investment,
and not with a view toward distribution or resale and that such holder is an
Accredited Investor. If such holder cannot make such representations because
they would be factually incorrect, it shall be a condition to such holder's
exercise of this Warrant, other than pursuant to a Cashless Exercise, that the
Company receive such other representations as the Company considers reasonably
necessary to assure the Company that the issuance of its securities upon
exercise of this Warrant shall not violate any United States or state securities
laws.

         Section 7.        Ownership and Transfer.

                  (a)      The Company shall maintain at its principal executive
offices (or such other office or agency of the Company as it may designate by
notice to the holder hereof), a register for this Warrant, in which the Company
shall record the name and address of the person in whose name this Warrant has
been issued, as well as the name and address of each


                                      -9-
<PAGE>   10

transferee. The Company may treat the person in whose name any Warrant is
registered on the register as the owner and holder thereof for all purposes,
notwithstanding any notice to the contrary, but in all events recognizing any
transfers made in accordance with the terms of this Warrant.

                  (b)      The Company is obligated to register the Warrant
Shares for resale under the Securities Act pursuant to the Registration Rights
Agreement and the initial holder of this Warrant (and certain assignees thereof)
is entitled to the registration rights in respect of the Warrant Shares as set
forth in the Registration Rights Agreement.

         Section 8.        Adjustment of Warrant Exercise Price and Number of
Shares. For purposes of this Section 8, the portion of each Warrant which
becomes exercisable on an Advance Date shall be treated as if it were a separate
Warrant based on the Warrant Exercise Price as determined on the Advance Date
and as if such portion of this Warrant were exercisable on the Issuance Date.
The Warrant Exercise Price and the number of shares of Common Stock issuable
upon exercise of this Warrant shall be adjusted from time to time as follows:

                  (a)      Adjustment of Warrant Exercise Price and Number of
Shares upon Issuance of Common Stock. If and whenever on or after the Issuance
Date of this Warrant, the Company issues or sells, or is deemed to have issued
or sold, any shares of Common Stock (other than (i) Excluded Securities and (ii)
shares of Common Stock which are issued or deemed to have been issued by the
Company in connection with an Approved Stock Plan or upon exercise or conversion
of the Other Securities) for a consideration per share less than a price (the
"APPLICABLE PRICE") equal to the lower of the Warrant Exercise Price in effect
immediately prior to such issuance or sale or the Closing Bid Price, then
immediately after such issue or sale the Warrant Exercise Price then in effect
shall be reduced to an amount equal to the price determined by multiplying the
Warrant Exercise Price in effect immediately prior thereto by a fraction, of
which the numerator shall be the total number of shares of Common Stock
outstanding immediately prior to the issuance of such additional shares plus the
number of shares of Common Stock which the aggregate consideration received
(determined as provided in Section 8(c) for the issuance of such additional
shares would purchase at the current Warrant Exercise Price, and of which the
denominator shall be the number of shares of Common Stock outstanding
immediately after the issuance of such additional shares. Such adjustment shall
be made successively whenever such an issuance is made. Upon each such
adjustment of the Warrant Exercise Price hereunder, the number of Warrant Shares
issuable upon exercise of this Warrant shall be adjusted to the number of shares
determined by multiplying the Warrant Exercise Price in effect immediately prior
to such adjustment by the number of Warrant Shares issuable upon exercise of
this Warrant immediately prior to such adjustment and dividing the product
thereof by the Warrant Exercise Price resulting from such adjustment.

                  (b)      Effect on Warrant Exercise Price of Certain Events.
For purposes of determining the adjusted Warrant Exercise Price under Section
8(a) above, the following shall be applicable:


                                      -10-
<PAGE>   11

                           (i)      Issuance of Options. If the Company in any
manner grants any Options and the lowest price per share for which one share of
Common Stock is issuable upon the exercise of any such Option or upon conversion
or exchange of any Convertible Securities issuable upon exercise of any such
Option is less than the Applicable Price, then such share of Common Stock shall
be deemed to be outstanding and to have been issued and sold by the Company at
the time of the granting or sale of such Option for such price per share. For
purposes of this Section 8(b)(i), the lowest price per share for which one share
of Common Stock is issuable upon exercise of such Options or upon conversion or
exchange of such Convertible Securities" shall be equal to the sum of the lowest
amounts of consideration (if any) received or receivable by the Company with
respect to any one share of Common Stock upon the granting or sale of the
Option, upon exercise of the Option or upon conversion or exchange of any
Convertible Security issuable upon exercise of such Option. No further
adjustment of the Warrant Exercise Price shall be made upon the actual issuance
of such Common Stock or of such Convertible Securities upon the exercise of such
Options or upon the actual issuance of such Common Stock upon conversion or
exchange of such Convertible Securities.

                           (ii)     Issuance of Convertible Securities. If the
Company in any manner issues or sells any Convertible Securities and the lowest
price per share for which one share of Common Stock is issuable upon the
conversion or exchange thereof is less than the Applicable Price, then such
share of Common Stock shall be deemed to be outstanding and to have been issued
and sold by the Company at the time of the issuance or sale of such Convertible
Securities for such price per share. For the purposes of this Section 8(b)(ii),
the lowest price per share for which one share of Common Stock is issuable upon
such conversion or exchange" shall be equal to the sum of the lowest amounts of
consideration (if any) received or receivable by the Company with respect to one
share of Common Stock upon the issuance or sale of the Convertible Security and
upon conversion or exchange of such Convertible Security. No further adjustment
of the Warrant Exercise Price shall be made upon the actual issuance of such
Common Stock upon conversion or exchange of such Convertible Securities, and if
any such issue or sale of such Convertible Securities is made upon exercise of
any Options for which adjustment of the Warrant Exercise Price had been or are
to be made pursuant to other provisions of this Section 8(b), no further
adjustment of the Warrant Exercise Price shall be made by reason of such issue
or sale.

                           (iii)    Change in Option Price or Rate of
Conversion. If the purchase price provided for in any Options, the additional
consideration, if any, payable upon the issue, conversion or exchange of any
Convertible Securities, or the rate at which any Convertible Securities are
convertible into or exchangeable for Common Stock changes at any time, the
Warrant Exercise Price in effect at the time of such change shall be adjusted to
the Warrant Exercise Price which would have been in effect at such time had such
Options or Convertible Securities provided for such changed purchase price,
additional consideration or changed conversion rate, as the case may be, at the
time initially granted, issued or sold and the number of Warrant Shares issuable
upon exercise of this Warrant shall be correspondingly readjusted. For purposes
of this Section 8(b)(iii), if the terms of any Option or Convertible Security
that was outstanding as of the Issuance Date of this Warrant are changed in the
manner described in the immediately preceding sentence, then such Option or
Convertible Security and the


                                      -11-

<PAGE>   12

Common Stock deemed issuable upon exercise, conversion or exchange thereof shall
be deemed to have been issued as of the date of such change. No adjustment
pursuant to this Section 8(b) shall be made if such adjustment would result in
an increase of the Warrant Exercise Price then in effect.

                  (c)      Effect on Warrant Exercise Price of Certain
Events. For purposes of determining the adjusted Warrant Exercise Price under
Sections 8(a) and 8(b), the following shall be applicable:

                           (i)      Calculation of Consideration Received. If
any Common Stock, Options or Convertible Securities are issued or sold or deemed
to have been issued or sold for cash, the consideration received therefore will
be deemed to be the net amount received by the Company therefore. If any Common
Stock, Options or Convertible Securities are issued or sold for a consideration
other than cash, the amount of such consideration received by the Company will
be the fair value of such consideration, except where such consideration
consists of marketable securities, in which case the amount of consideration
received by the Company will be the Market Price of such securities on the date
of receipt of such securities. If any Common Stock, Options or Convertible
Securities are issued to the owners of the non-surviving entity in connection
with any merger in which the Company is the surviving entity, the amount of
consideration therefore will be deemed to be the fair value of such portion of
the net assets and business of the non-surviving entity as is attributable to
such Common Stock, Options or Convertible Securities, as the case may be. The
fair value of any consideration other than cash or securities will be determined
jointly by the Company and the holders of Warrants representing at least
two-thirds (2/3) of the Warrant Shares issuable upon exercise of the Warrants
then outstanding. If such parties are unable to reach agreement within ten (10)
days after the occurrence of an event requiring valuation (the "VALUATION
EVENT"), the fair value of such consideration will be determined within five (5)
Business Days after the tenth (10th) day following the Valuation Event by an
independent, reputable appraiser jointly selected by the Company and the holders
of Warrants representing at least two-thirds (2/3) of the Warrant Shares
issuable upon exercise of the Warrants then outstanding. The determination of
such appraiser shall be final and binding upon all parties and the fees and
expenses of such appraiser shall be borne jointly by the Company and the holders
of Warrants.

                           (ii)     Integrated Transactions. In case any Option
is issued in connection with the issue or sale of other securities of the
Company, together comprising one integrated transaction in which no specific
consideration is allocated to such Options by the parties thereto, the Options
will be deemed to have been issued for a consideration of $.01.

                           (iii)    Treasury Shares. The number of shares of
Common Stock outstanding at any given time does not include shares owned or held
by or for the account of the Company, and the disposition of any shares so owned
or held will be considered an issue or sale of Common Stock.

                           (iv)     Record Date. If the Company takes a record
of the holders of Common Stock for the purpose of entitling them (1) to receive
a dividend or other distribution payable in Common Stock, Options or in
Convertible Securities or (2) to subscribe for or


                                      -12-
<PAGE>   13

purchase Common Stock, Options or Convertible Securities, then such record date
will be deemed to be the date of the issue or sale of the shares of Common Stock
deemed to have been issued or sold upon the declaration of such dividend or the
making of such other distribution or the date of the granting of such right of
subscription or purchase, as the case may be.

                  (d)      Adjustment of Warrant Exercise Price upon Subdivision
or Combination of Common Stock. If the Company at any time after the date of
issuance of this Warrant subdivides (by any stock split, stock dividend,
recapitalization or otherwise) one or more classes of its outstanding shares of
Common Stock into a greater number of shares, any Warrant Exercise Price in
effect immediately prior to such subdivision will be proportionately reduced and
the number of shares of Common Stock obtainable upon exercise of this Warrant
will be proportionately increased. If the Company at any time after the date of
issuance of this Warrant combines (by combination, reverse stock split or
otherwise) one or more classes of its outstanding shares of Common Stock into a
smaller number of shares, any Warrant Exercise Price in effect immediately prior
to such combination will be proportionately increased and the number of Warrant
Shares issuable upon exercise of this Warrant will be proportionately decreased.
Any adjustment under this Section 8(d) shall become effective at the close of
business on the date the subdivision or combination becomes effective.

                  (e)      Distribution of Assets. If the Company shall declare
or make any dividend or other distribution of its assets (or rights to acquire
its assets) to holders of Common Stock, by way of return of capital or otherwise
(including, without limitation, any distribution of cash, stock or other
securities, property or options by way of a dividend, spin off,
reclassification, corporate rearrangement or other similar transaction) (a
"DISTRIBUTION"), at any time after the issuance of this Warrant, then, in each
such case: either (x) the number of Warrant Shares obtainable upon exercise of
this Warrant shall be increased to a number of shares equal to the number of
shares of Common Stock obtainable immediately prior to the close of business on
the record date fixed for the determination of holders of Common Stock entitled
to receive the Distribution multiplied by a fraction of which (A) the numerator
shall be the Closing Sale Price of the Common Stock on the trading day
immediately preceding such record date, and (B) the denominator shall be the
Closing Sale Price of the Common Stock on the trading day immediately preceding
such record date minus the value of the Distribution (as determined in good
faith by the Company's Board of Directors) applicable to one share of Common
Stock; or (y) in the event that the Distribution is of common stock of a company
whose common stock is traded on a national securities exchange or a national
automated quotation system, then the holder of this Warrant shall receive an
additional warrant to purchase Common Stock, the terms of which shall be
identical to those of this Warrant, except that such warrant shall be
exercisable into the amount of the assets that would have been payable to the
holder of this Warrant pursuant to the Distribution had the holder exercised
this Warrant immediately prior to such record date and with an exercise price
equal to the amount by which the exercise price of this Warrant was decreased
with respect to the Distribution pursuant to the terms of the immediately
preceding clause (i).

                  (f)      Certain Events. If any event occurs of the type
contemplated by the provisions of this Section 8 but not expressly provided for
by such provisions (including, without limitation, the granting of stock
appreciation rights, phantom stock rights or other


                                      -13-
<PAGE>   14

rights with equity features), then the Company's Board of Directors will make an
appropriate adjustment in the Warrant Exercise Price and the number of shares of
Common Stock obtainable upon exercise of this Warrant so as to protect the
rights of the holders of the Warrants; provided that no such adjustment pursuant
to this Section 8(f) will increase the Warrant Exercise Price or decrease the
number of shares of Common Stock obtainable as otherwise determined pursuant to
this Section 8.

                  (g)      Notices.

                           (i)      Immediately upon any adjustment of the
Warrant Exercise Price, the Company will give written notice thereof to the
holder of this Warrant, setting forth in reasonable detail, and certifying, the
calculation of such adjustment.

                           (ii)     The Company will give written notice to the
holder of this Warrant at least ten (10) days prior to the date on which the
Company closes its books or takes a record (A) with respect to any dividend or
distribution upon the Common Stock, including an event described in Section
8(e), (B) with respect to any pro rata subscription offer to holders of Common
Stock or (C) for determining rights to vote with respect to any Organic Change
(as defined below), dissolution or liquidation, provided that such information
shall be made known to the public prior to or in conjunction with such notice
being provided to such holder, which notice shall set forth the effect on such
holder if the holder fails to exercise the Warrant prior to such event.

                           (iii)    The Company will also give written notice to
the holder of this Warrant at least ten (10) days prior to the date on which any
Organic Change, dissolution or liquidation will take place, provided that such
information shall be made known to the public prior to or in conjunction with
such notice being provided to such holder.

         Section 9.        Purchase Rights; Reorganization, Reclassification,
                           Consolidation, Merger or Sale.

                  (a)      In addition to any adjustments pursuant to Section 8
above, if at any time the Company grants, issues or sells any Options,
Convertible Securities or rights to purchase stock, warrants, securities or
other property pro rata to the record holders of any class of Common Stock (the
"PURCHASE RIGHTS"), then upon the exercise of this Warrant the holder of this
Warrant will be entitled to acquire, upon the terms applicable to such Purchase
Rights, the aggregate Purchase Rights which such holder could have acquired if
such holder had held the number of shares of Common Stock acquirable upon
complete exercise of this Warrant immediately before the date on which a record
is taken for the grant, issuance or sale of such Purchase Rights, or, if no such
record is taken, the date as of which the record holders of Common Stock are to
be determined for the grant, issue or sale of such Purchase Rights.

(b)      Any recapitalization, reorganization, reclassification, consolidation,
merger, sale of all or substantially all of the Company's assets to another
Person or other transaction in each case which is effected in such a way that
holders of Common Stock are entitled to receive (either directly or upon
subsequent liquidation) stock, securities or assets with respect to or in


                                      -14-

<PAGE>   15

exchange for Common Stock is referred to herein as an "ORGANIC CHANGE". In the
case of any Organic Change, the holder of this Warrant shall thereafter have the
right upon exercise to purchase the kind and amount of shares of stock and other
securities and property receivable upon such Organic Change which the holder of
this Warrant would have received had all Warrant Shares issuable upon exercise
of this Warrant been issued immediately prior to such Organic Change at a price
equal to the Warrant Exercise Price then in effect pertaining to this Warrant
(the kind, amount and price of such stock and other securities to be subject to
adjustment as herein provided).

         Section 10.       Redemption. The Company may redeem, in cash, the
Warrants at any time at a redemption price of $.01 per Warrant, upon thirty (30)
days prior written notice, provided that within three days of the date of the
redemption notice the Closing Bid Price is not less than $4.00 per share for ten
(10) consecutive trading days and the resale of the Warrant Shares are covered
by an effective registration statement. The holder of the Warrant shall be
entitled to exercise this Warrant after receipt of the redemption notice, but
prior to the redemption of this Warrant by the Company.

         Section 11.       Lost, Stolen, Mutilated or Destroyed Warrant. If this
Warrant is lost, stolen, mutilated or destroyed, the Company shall promptly, on
receipt of an indemnification undertaking (or, in the case of a mutilated
Warrant, the Warrant), issue a new Warrant of like denomination and tenor as
this Warrant so lost, stolen, mutilated or destroyed.

         Section 12.       Notice. Any notices, consents, waivers or other
communications required or permitted to be given under the terms of this Warrant
must be in writing and will be deemed to have been delivered: (i) upon receipt,
when delivered personally; (ii) upon receipt, when sent by facsimile (provided
confirmation of transmission is mechanically or electronically generated and
kept on file by the sending party); or (iii) one Business Day after deposit with
a nationally recognized overnight delivery service, in each case properly
addressed to the party to receive the same. The addresses and facsimile numbers
for such communications shall be:

         If to the Holder:
                  Mark Angelo
                  c/o May Davis Group, Inc.
                  1 World Trade Center, Suite 8735
                  New York, NY 10048
                  Telephone:   (212) 775-7400

         If to the Company:
                  Advanced Viral Research Corp.
                  200 Corporate Boulevard South, Suite 1601
                  Yonkers, New York 10701
                  Telephone:   (914) 376-7383
                  Facsimile:   (914) 376-7368
                  Attention:   Shalom Hirschman, M.D.

         with a copy to:


                                      -15-
<PAGE>   16

                  Wolf, Block, Schorr & Solis-Cohen, LLP
                  250 Park Avenue, 10th floor
                  New York, NY 10177
                  Telephone:   (212) 883-4901
                  Facsimile:   (212) 986-0604
                  Attention:   Robert Fischer, Esq.

If to a holder of this Warrant, to it at the address and facsimile number set
forth in the Credit Agreement, with copies to such holder's representatives as
set forth in such Credit Agreement, or at such other address and facsimile as
shall be delivered to the Company upon the issuance or transfer of this Warrant.
Each party shall provide five days' prior written notice to the other party of
any change in address or facsimile number. Written confirmation of receipt (A)
given by the recipient of such notice, consent, waiver or other communication,
(B) mechanically or electronically generated by the sender's facsimile machine
containing the time, date, recipient facsimile number and an image of the first
page of such transmission or (C) provided by a nationally recognized overnight
delivery service shall be rebuttable evidence of personal service, receipt by
facsimile or receipt from a nationally recognized overnight delivery service in
accordance with clause (i), (ii) or (iii) above, respectively.

         Section 13.       Date. The date of this Warrant is February 9, 2001.
This Warrant, in all events, shall be wholly void and of no effect after the
close of business on the Expiration Date, except that notwithstanding any other
provisions hereof, the provisions of Section 7(c) shall continue in full force
and effect after such date as to any Warrant Shares or other securities issued
upon the exercise of this Warrant.

         Section 14.       Amendment and Waiver. Except as otherwise provided
herein, the provisions of the Warrants may be amended and the Company may take
any action herein prohibited, or omit to perform any act herein required to be
performed by it, only if the Company has obtained the written consent of the
holders of Warrants representing at least two-thirds (2/3) of the Warrant Shares
issuable upon exercise of the Warrants then outstanding; provided that no such
action may increase the Warrant Exercise Price or decrease the number of shares
or class of stock obtainable upon exercise of any Warrant without the written
consent of the holder of such Warrant.

         Section 15.       Descriptive Headings; Governing Law. The descriptive
headings of the several sections and paragraphs of this Warrant are inserted for
convenience only and do not constitute a part of this Warrant. The corporate
laws of the State of Delaware shall govern all issues concerning the relative
rights of the Company and its stockholders. All other questions concerning the
construction, validity, enforcement and interpretation of this Warrant shall be
governed by the internal laws of the State of New York, without giving effect to
any choice of law or conflict of law provision or rule (whether of the State of
New York, or any other jurisdiction) that would cause the application of the
laws of any jurisdiction other than the State of New York.


                            [SIGNATURE PAGE FOLLOWS]


                                      -16-
<PAGE>   17


         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
_________________, its ___________________, as of the 9th day February, 2001.


                                    ADVANCED VIRAL RESEARCH CORP.



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


                                      -17-
<PAGE>   18

                              EXHIBIT A TO WARRANT

                                SUBSCRIPTION FORM

        TO BE EXECUTED BY THE REGISTERED HOLDER TO EXERCISE THIS WARRANT

                          ADVANCED VIRAL RESEARCH CORP.

         The undersigned holder hereby exercises the right to purchase
_________________ of the shares of Common Stock ("WARRANT SHARES") of Advanced
Viral Research Corp., a Delaware corporation (the "COMPANY"), evidenced by the
attached Warrant (the "WARRANT"). Capitalized terms used herein and not
otherwise defined shall have the respective meanings set forth in the Warrant.

         1.       Form of Warrant Exercise Price. The Holder intends that
payment of the Warrant Exercise Price shall be made as:

                  ____________      a "Cash Exercise" with respect to
                                    _________________ Warrant Shares; and/or

                  ____________      a "Cashless Exercise" with respect to
                                    _______________ Warrant Shares (to the
                                    extent permitted by the terms of the
                                    Warrant).

         2.       Payment of Warrant Exercise Price. In the event that the
holder has elected a Cash Exercise with respect to some or all of the Warrant
Shares to be issued pursuant hereto, the holder shall pay the sum of
$___________________ to the Company in accordance with the terms of the Warrant.

         3.       Delivery of Warrant Shares. The Company shall deliver to the
holder __________ Warrant Shares in accordance with the terms of the Warrant.

Date:                   ,
     __________________  __  _______


   Name of Registered Holder


By:
   _________________________________
   Name:
   Title:


                                      -18-