EXHIBIT 3.1

               CERTIFICATE OF DESIGNATION, PREFERENCES AND RIGHTS

                                     of the

                      SERIES A CONVERTIBLE PREFERRED STOCK

                                       of

                                 ANTIGENICS INC.

               Pursuant to Section 151 of the General Corporation
                          Law of the State of Delaware



         We, Garo Armen, Chief Executive Officer and Chairman, and Claudia
Wernick, Assistant Secretary, of Antigenics Inc. (the "Corporation"), a
corporation organized and existing under the laws of the State of Delaware, in
accordance with Section 151 of the Delaware General Corporation Law, certify:

     FIRST: The Certificate of Incorporation of the Corporation, as currently
     amended, authorizes the issuance of up to 25,000,000 shares of preferred
     stock, par value $0.01 per share, in one or more series, with such
     designations, preferences and relative, participating, optional or other
     special rights, and qualifications, limitations or restrictions thereof, as
     may be stated and expressed in a resolution or resolutions providing for
     the issuance of any such series adopted by the Board of Directors of the
     Corporation, pursuant to authority expressly vested in the Board of
     Directors by the Certificate of Incorporation of the Corporation.


     SECOND: The Board of Directors of the Corporation, through a duly
     authorized committee of the Board of Directors, duly adopted the following
     resolutions authorizing the creation of a new series of such preferred
     stock, to be known as "Series A Convertible Preferred Stock", stating that
     31,620 shares of the authorized and unissued preferred stock shall
     constitute such series, and setting forth a statement of the voting powers,
     designation, preferences and relative, participating, optional or other
     special rights, and the qualifications, limitations and restrictions
     thereof as follows:


         BE IT RESOLVED, that the terms of the Series A Convertible Preferred
Stock shall be as follows:

1. Designation of Preferred Stock. The rights, preferences, privileges and
restrictions granted to and imposed on the Series A Convertible Preferred Stock,
$0.01 par value per share (the "Series A Preferred Stock" or the "Preferred
Stock"), are set forth below. The number of shares of Series A Preferred Stock
shall initially be 31,620, subject to decrease (but not below the number of
shares of such series then outstanding) from time to time by action of the Board
of Directors.


2. Rank. The Series A Preferred Stock shall rank senior to the Common Stock,
senior to any other class or series of capital stock of the Corporation the
terms of which do not expressly provide that it ranks on a parity with or senior
to the Series A Preferred Stock (collectively and together with the Common
Stock, the "Junior Stock"), pari passu with any class or series of capital stock
of the Corporation the terms of which expressly provide that it ranks on a
parity with the Series A Preferred Stock (collectively, the "Parity Stock"), and
junior to any other class or series of capital stock of the Corporation the
terms of which expressly provide that it ranks senior to the Series A Preferred
Stock (collectively, "Senior Stock"); provided, that prior to September 24,
2005, unless fewer than 16,000 shares of Series A Preferred Stock remain
outstanding, the Corporation shall have the right to issue shares of capital



stock ranking senior to the Series A Preferred Stock as to receipt of amounts
distributable upon any liquidation, dissolution or winding up of the Corporation
("Liquidation") and as to dividends, only upon the approval of record holders of
a majority of the shares of Series A Preferred Stock outstanding on the date of
such approval; provided, further, however, that the previous clause in no way
shall restrict the Corporation from adopting, at any time, a rights plan.
Nothing in this Certificate shall prevent or otherwise affect the declaration or
payment of any dividend or distribution on the Common Stock or any other class
or series of capital stock of the Corporation outstanding from time to time
other than upon a Liquidation, as long as the dividends are accruing on the
Series A Preferred Stock as provided in Section 3.


3. Dividends and Distributions. The holder of each share of Series A Preferred
Stock shall be entitled to receive dividends on such share of Preferred Stock
from and including the date of issuance of such share to but excluding the date
of the redemption or conversion of such share or the date of Liquidation. Such
dividends shall accrue on a daily basis from the date of issuance (computed on
the basis of a 360-day year of twelve 30-day months) on the Preference Amount of
such share, compounded as of the end of each of the Corporation's fiscal
quarters at a rate per annum equal to the Accumulation Rate, and such dividends
shall accrue whether or not they have been declared and whether or not there are
profits, surplus or other funds of the Corporation legally available for the
payment of dividends. The holders of shares of Preferred Stock shall not be
entitled to receive or participate in any dividends or other distributions made
by the Corporation that are not provided for in this Section 3, except as
provided for in Section 6.8.


4. Liquidation, Dissolution or Winding Up.

     4.1. Liquidation Preference. In the event of any Liquidation, either
voluntary or involuntary, distributions to the holders of the Series A Preferred
Stock shall be made in the following manner:

     4.1.1. Each holder of Series A Preferred Stock shall be entitled to
receive, after distribution of any of the assets of the Corporation to the
holders of any Senior Stock, pro rata with any shares of Parity Stock (in
proportion to their respective liquidation preferences) and prior and in
preference to any distribution of any of the assets of the Corporation to the
holders of any shares of Junior Stock, by reason of their ownership of such
stock, an amount per share of Series A Preferred Stock held by such holder (the
"Liquidation Amount") equal to the Preference Amount as of the date of the
Liquidation. If after distribution of any of the assets of the Corporation to
the holders of any shares of Senior Stock, the assets of the Corporation shall
be insufficient to permit the payment in full to the holders of the Series A
Preferred Stock of the full Liquidation Amount and the payment in full to the
holders of any shares of Parity Stock of the liquidation preference applicable
to such Parity Stock, then the entire remaining assets of the Corporation
legally available for distribution shall be distributed ratably among the
holders of Series A Preferred Stock and Parity Stock, to the exclusion of any
Junior Stock, in accordance with the respective amounts which would be payable
in respect of the shares held by each of them upon such distribution if all
amounts payable on or in respect of such shares were paid in full.


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     4.1.2. After payment has been made to the holders of Series A Preferred
Stock of the full amount to which they are entitled pursuant to Section 4.1.1,
the holders of Series A Preferred Stock shall not be entitled to any further
distributions, with respect to the shares of Series A Preferred Stock, of the
assets of the Corporation with respect to the Liquidation.

     4.1.3. The Corporation shall give written notice of a Liquidation to each
holder of record of Series A Preferred Stock at least 30 days prior to the date
for payment or distribution to stockholders stated in the Corporation's notice.

     4.2. Change of Control. A Change of Control of the Corporation shall not be
deemed a Liquidation for purposes of this Section 4.

     4.3. Distributions Other Than Cash. Whenever any distribution provided for
in this Section 4 shall be payable in property other than cash, the value of
such distribution shall be the Current Market Price of such property as of the
record date for holders entitled to participate in the Liquidation.


5. Voting Rights; Amendments.

     5.1. Voting Rights. Except as provided in Section 2 and as otherwise
required by law, the holders of Series A Preferred Stock shall not have any
voting rights. Each holder of Series A Preferred Stock shall have, on any matter
submitted to the holders of Series A Preferred Stock, one vote for each share
held.


6. Conversion Rights. The holders of Series A Preferred Stock shall have the
following rights with respect to the conversion of the Series A Preferred Stock
into shares of Common Stock:

     6.1. General. Subject to and in compliance with the provisions of this
Section 6, shares of Series A Preferred Stock may, at the option of the holder
thereof, be converted at any time and from time to time into the number of
validly issued, fully-paid and non-assessable shares of Common Stock equal to
the product obtained by multiplying the Conversion Rate (determined as provided
in Section 6.2) by the number of shares of Preferred Stock held by such holder
being converted.

     6.2. Conversion Rate. The conversion rate in effect at any time for shares
of the Series A Preferred Stock to be converted (the "Conversion Rate") shall be
the quotient obtained by dividing the Preference Amount of the shares of
Preferred Stock to be converted by the Conversion Value then in effect for such
shares.

     6.3. Conversion Value. The Conversion Value shall initially be $15.81, and
shall be adjusted from time to time in accordance with Section 6.4 hereof (as so
adjusted, the "Conversion Value").

     6.4. Adjustments to Conversion Value. In the event at any time of (a) a
subdivision (by a stock split, stock dividend or similar transaction) by the
Corporation of outstanding shares of Common Stock into a greater number of
shares of Common Stock, or (b) a combination (by a reverse stock split or
similar transaction) of the Corporation of outstanding shares of Common Stock


                                       7


into a smaller number of shares of Common Stock (any of the foregoing being
referred to as an "Extraordinary Common Stock Event"), the Conversion Value
shall, effective as of the time such Extraordinary Common Stock Event becomes
effective, be adjusted to equal the product of (x) the Conversion Value in
effect immediately prior to the effectiveness of such Extraordinary Common Stock
Event, multiplied by (y) a fraction, the numerator of which shall be the number
of shares of Common Stock outstanding immediately prior to such Extraordinary
Common Stock Event and the denominator of which shall be the number of shares of
Common Stock outstanding immediately after the effectiveness of such
Extraordinary Common Stock Event.

         6.5 Corporate Change. Prior to the consummation of any Corporate
Change, the Corporation shall make appropriate provisions to ensure that each
holder of Preferred Stock shall have the right to receive in lieu of the shares
of Common Stock that the holder otherwise would have been entitled to receive
upon conversion, the stock, securities or assets that the holder would have
received in connection with the Corporate Change if the holder had converted the
holder's Preferred Stock immediately prior to the close of business on the
record date for holders of Common Stock entitled to receive the stock,
securities or assets delivered to such holders as a result of the Corporate
Change (assuming such holder failed to exercise any rights of election and
received per share the kind and amount of consideration receivable per share by
a plurality of the non-electing shares of Common Stock). The Corporation shall
not effect any Corporate Change unless, prior to the consummation of the
Corporate Change, the successor corporation (if other than the Corporation) or
the purchasing Person assumes by written instrument the obligation to deliver to
each holder of Series A Preferred Stock such shares of stock, securities or
assets that the holder is entitled to receive in accordance with this Section
6.5.

6.6      Conversion Procedure.

     (a) To exercise its conversion rights pursuant to this Section 6, a holder
of Series A Preferred Stock shall surrender the certificate or certificates
representing the shares being converted to the Corporation at its principal
office or, if the Corporation has appointed an agent and provided the holders of
Series A Preferred Stock notice thereof, at the office of the agent designated
by the Corporation for such purpose, together with written notice to the
Corporation substantially in the form of Exhibit A hereto (a "Conversion
Notice") that such holder elects to convert such shares, or if fewer than all
the shares represented by a single share certificate are to be converted, the
number of shares represented thereby to be converted. The certificate or
certificates for shares of Series A Preferred Stock surrendered for conversion
shall be accompanied by proper assignment thereof to the Corporation or in
blank.

     (b) Each conversion of Series A Preferred Stock shall be deemed to have
been effected as of the close of business on the effective date of such
conversion as specified in the Conversion Notice (the "Conversion Date");
provided, however, that the Conversion Date shall not be a date earlier than the
date such Conversion Notice is received by the Corporation (or its designated
agent), and if such Conversion Notice does not specify a conversion date, the
Conversion Date shall be deemed to be the date such Conversion Notice is
received by the Corporation (or its designated agent). On the Conversion Date,


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the rights as a holder of the Series A Preferred Stock to be converted
(including the right to receive dividends thereon, except as provided in Section
6.8 hereof) shall cease, and the person or persons in whose name or names any
certificate or certificates for shares of Common Stock are to be issued upon
such conversion shall be deemed to have become the holder or holders of record
of the shares of Common Stock represented thereby

                  (c) Promptly after the Conversion Date (and in any event
within three Business Days), the Corporation shall deliver to the converting
holder at the address set forth in the conversion notice (a) a certificate or
certificates representing, in the aggregate, the number of shares of Common
Stock issued upon such conversion, in the same name or names as the certificates
representing the converted shares or in such other name or names as the
converting holder shall specify (subject to any applicable legal, contractual or
other restrictions on transfer) and in such denomination or denominations as the
converting holder shall specify and a check for cash with respect to any
fractional interest in a share of Common Stock as provided in Section 6.7, and
(b) a certificate representing any shares of Series A Preferred Stock that were
represented by the certificate or certificates delivered to the Corporation in
connection with such conversion but that were not converted.

                  (d) The issuance of certificates for shares of Common Stock
upon the conversion of Series A Preferred Stock shall be made without charge to
the holder of such Preferred Stock for any issuance tax in respect thereof if
issued in the name of such holder, and otherwise any certificates shall not be
issued until payment of any applicable transfer tax has been made by such
holder.

         6.7 Cash in Lieu of Fractional Shares. No fractional share of Common
Stock or scrip representing a fractional share shall be issued upon the
conversion of any shares of Series A Preferred Stock, provided, that if more
than one share of Preferred Stock shall be surrendered for conversion at any one
time by the same holder, the number of full shares of Common Stock issuable upon
conversion thereof shall be computed on the basis of the aggregate number of
shares of Series A Preferred Stock so surrendered. Instead of any fractional
share of Common Stock which would otherwise be issuable upon conversion of any
shares of Series A Preferred Stock, the Corporation shall pay to the holder of
the converted shares of Series A Preferred Stock cash in respect of any such
fractional share of Common Stock in an amount equal to the same fraction of the
Current Market Price per share of Common Stock on the Conversion Date.

     6.8 Certain Distributions. Upon the conversion by any holder of Series A
Preferred Stock of shares of Series A Preferred Stock into Common Stock pursuant
to this Section 6, such holder shall have the right to receive, and shall be
paid promptly thereafter (and in any event within three Business Days), any
extraordinary dividends or distributions as shall have been declared and paid or
made by the Corporation on or with respect to the Common Stock as a class during
the period commencing on the date on which the shares of Series A Preferred
Stock being converted were issued and ending on the Conversion Date in such
amounts as such holder would have received had such holder converted such shares
of Series A Preferred Stock immediately prior to the close of business on the
record date established for holders of Common Stock entitled to receive such
dividends or distributions without interest; provided, however, that the terms
of this Section 6.8 shall not apply to ordinary cash dividends or if an
adjustment to the Conversion Rate was made with respect to such distribution.
Upon effecting any dividend or distribution in which a holder of shares of
Preferred Stock shall be entitled to participate following conversion as
contemplated by this Section 6.8, the Corporation shall place in escrow on
customary business terms at the Corporation's expense, for the benefit of the
holders of the Series A Preferred Stock, the property to which such holders
shall be entitled upon conversion as contemplated by this Section 6.8, and such
property shall be maintained in escrow at the Corporation's expense until such
time as the related shares of Series A Preferred Stock have been converted or
redeemed; provided, however, that the Corporation may, at its expense,
substitute another arrangement for such escrow arrangement to the extent
advisable based upon of consultation with the Corporation's outside counsel in


                                       9


connection with any tax treatment desired to be achieved in connection with any
distribution of property by the Corporation.

     6.9 Notice to Holders. In the event the Corporation shall propose to take
or otherwise undergo any action of the type described in Section 6.4 (but only
if the action of the type described in Section 6.4 would result in an adjustment
in the Conversion Value), engage in a Corporate Change as contemplated by
Section 6.5 or pay or make an extraordinary dividend or distribution of the type
described in Section 6.8, the Corporation shall give notice to each holder of
shares of Preferred Stock in the manner set forth in Section 11, which notice
shall specify the record date, if any, with respect to any such action and the
approximate date on which such action is to take place. Such notice shall also
set forth such facts as are reasonably necessary to indicate the effect of such
action (to the extent such effect may be known at the date of such notice) on
the Conversion Value and the number, kind or class of shares or other securities
or property which shall be deliverable upon conversion of shares of Preferred
Stock. In the case of any action which would require the fixing of a record
date, such notice shall be given prior to such record date, and in case of all
other action, such notice shall be given at least five Business Days prior to
the taking of such proposed action. Failure to give such notice, or any defect
therein, shall not affect the legality or validity or any such action.

     6.10 Valid Issuance. All shares of Common Stock which may be issued upon
conversion of the shares of Preferred Stock shall upon issuance by the
Corporation be duly and validly issued, fully paid and nonassessable.


7. Redemptions

     7.1. Redemptions At Holder's Option. The holders of Series A Preferred
Stock shall not have the right to require the Corporation to redeem shares of
Series A Preferred Stock.

     7.2. Redemption At Corporation's Option. The Corporation shall not have the
right under this Certificate to redeem outstanding shares of Series A Preferred
Stock prior to September 24, 2013. On or after September 24, 2013, the
Corporation, at its option, may redeem the shares of Series A Preferred Stock,
in whole or in part, out of funds legally available therefore, at any time or
from time to time, subject to the notice provisions and provisions for partial
redemption described below, at a redemption price for each share of Series A
Preferred Stock redeemed of $1,000, provided that, the Corporation shall also
pay to holders of shares of Series A Preferred Stock being redeemed all accrued
but unpaid dividends at the time of payment of the redemption price. In case the
Corporation shall desire to exercise the right to redeem the shares of Series A
Preferred Stock, in whole or in part, pursuant to this Section 7.2, it shall fix
a date for redemption, and it, or at its request, a transfer agent, shall mail
or cause to be mailed a notice of such redemption at least twenty (20) and not
more than sixty (60) days prior the date fixed for redemption to the record
holders of the shares of Series A Preferred Stock to be redeemed at their last
addresses as the same appear on the Corporation's stock records. Such mailing
shall be by first class mail. The notice if mailed in the manner herein provided
shall be conclusively presumed to have been duly given, whether or not the
holder receives such notice. In any case, failure to give such notice by mail or
any defect in the notice to the holder of any share of Series A Preferred Stock
designated for redemption shall not affect the validity of the proceedings for


                                       10


the redemption of any other share of Series A Preferred Stock. Each such notice
of redemption shall specify the number of shares of Series A Preferred Stock to
be redeemed, the date fixed for redemption, the redemption price at which such
shares of Preferred Stock are to be redeemed, that payment will be made upon
presentation and surrender of the certificate or certificates representing such
shares of Series A Preferred Stock, that dividends accrued to (but excluding)
the date fixed for redemption will be paid as specified in said notice, and that
on and after said date dividends thereon or on the portion thereof to be
redeemed will cease to accrue. Such notice shall also state the current
Conversion Value and the date on which the right to convert such shares of
Preferred Stock into Common Stock will expire. If fewer than all the outstanding
shares of Series A Preferred Stock are to be redeemed, shares to be redeemed
shall be selected by the Corporation from outstanding shares of Series A
Preferred Stock not previously called for redemption by lot or pro rata (as near
as may be) or by any other equitable method determined by the Corporation in its
sole discretion. If notice of redemption has been given as above provided, on
and after the date fixed for redemption (unless the Corporation shall default in
the payment of the redemption price, together with accrued and unpaid dividends
to (but excluding) said date), dividends on such shares of Series A Preferred
Stock so called for redemption shall cease to accrue and such shares of Series A
Preferred Stock shall be deemed no longer outstanding and the holders thereof
shall have no right in respect of such shares of Series A Preferred Stock except
the right to receive the redemption price thereof and accrued and unpaid
dividends to (but excluding) the date fixed for redemption, without interest
thereon. If fewer than all the shares of Series A Preferred Stock represented by
any certificate are redeemed, a new certificate shall be issued representing the
unredeemed shares without cost to the holder thereof .


8. Reservation of Stock. The Corporation shall at all times reserve and keep
available out of its authorized but unissued shares of Common Stock (or out of
its authorized shares of Common Stock held in the treasury of the Corporation),
for the purpose of effecting the conversion of the Series A Preferred Stock, the
full number of shares of Common Stock then issuable upon conversion pursuant to
Section 6 of all outstanding shares of Series A Preferred Stock.


9. Transfer. The Corporation shall keep at its principal office a register for
the registration of shares of Series A Preferred Stock. Upon the surrender of
any certificate representing Preferred Stock at the Corporation's principal
office accompanied by proper assignment thereof to the Corporation or in blank,
the Corporation shall, at the request of the record holder of the certificate,
execute and deliver a new certificate or certificates in exchange representing
in the aggregate the number of shares of Preferred Stock represented by the
surrendered certificate. Each new certificate shall be registered in the name
and represent the number of shares of Preferred Stock requested by the holder of
the surrendered certificate and shall be substantially identical in form to the
surrendered certificate. Any transfer of Series A Preferred Stock shall be
subject to any applicable legal, contractual or other restrictions on transfer
and the payment of any applicable transfer taxes by the transferring holder.

         Every share of Series A Preferred Stock that bears or is required under
this Section 9 to bear the legend set forth in this Section 9 (together with any
Common Stock issued upon conversion of the Series A Preferred Stock and required
to bear the legend set forth below, collectively, the "Restricted Securities")
shall be subject to the restrictions on transfer set forth in this Section 9
(including those set forth in the legend set forth below) unless such


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restrictions on transfer shall be waived by written consent of the Corporation,
and the holder of each such Restricted Securities, by such holder's acceptance
thereof, agrees to be bound by all such restrictions on transfer. As used in
this Sections 9, the term "transfer" encompasses any sale, pledge, transfer or
other disposition of any Restricted Securities.

         Every share of Series A Preferred Stock, and every certificate
evidencing such Series A Preferred Stock (and all securities issued in exchange
therefor or substitution thereof, other than Common Stock, if any, issued upon
conversion therefor) shall bear a legend in substantially the following form,
unless such Series A Preferred Stock has been sold pursuant to a registration
statement that has been declared effective under the Securities Act (and which
continues to be effective at the time of such transfer), or unless otherwise
agreed by the Corporation in writing:

THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"). THE HOLDER HEREOF, BY PURCHASING THIS SECURITY,
AGREES FOR THE BENEFIT OF THE CORPORATION THAT THIS SECURITY MAY NOT BE RESOLD,
PLEDGED OR OTHERWISE TRANSFERRED OTHER THAN (1) TO THE CORPORATION, (2) IN AN
OFFSHORE TRANSACTION (AS DEFINED IN REGULATION S UNDER THE SECURITIES ACT) IN
ACCORDANCE WITH REGULATION S UNDER THE SECURITIES ACT, (3) PURSUANT TO AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144 (IF
APPLICABLE) UNDER THE SECURITIES ACT OR (4) PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN EACH CASE IN ACCORDANCE WITH
ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES. BY PURCHASING
THIS SECURITY, THE HOLDER REPRESENTS AND AGREES FOR THE BENEFIT OF THE
CORPORATION THAT IT IS HOLDING THIS SECURITY FOR INVESTMENT PURPOSES AND NOT FOR
DISTRIBUTION. THE HOLDER HEREOF WILL NOT, DIRECTLY OR INDIRECTLY, ENGAGE IN ANY
HEDGING TRANSACTIONS WITH REGARD TO THIS SECURITY OR ANY COMMON STOCK ISSUABLE
UPON CONVERSION OF THIS SECURITY EXCEPT AS PERMITTED BY THE SECURITIES ACT.

         Any Series A Preferred Stock, any certificate evidencing such Series A
Preferred Stock (and all securities issued in exchange therefor or substitution
thereof, other than Common Stock, if any, issued upon conversion therefor) shall
also bear a legend in substantially the following form:

THE HOLDER HEREOF, BY PURCHASING THIS SECURITY, AGREES FOR THE BENEFIT OF THE
CORPORATION THAT THIS SECURITY MAY NOT BE RESOLD, PLEDGED OR OTHERWISE
TRANSFERRED WITHOUT THE CORPORATION'S PRIOR WRITTEN CONSENT, WHICH MAY BE
WITHHELD AT ITS ABSOLUTE DISCRETION, OTHER THAN TO THE HOLDER'S DEVISEES UPON
THE HOLDER'S DEATH, PURSUANT TO A COURT ORDER, OR IN A TRANSFER IN CONNECTION
WITH ESTATE PLANNING FOR WHICH THE HOLDER PROVIDES A LEGAL OPINION SATISFACTORY
TO THE CORPORATION THAT STATES THAT THE TRANSFER DOES NOT CONSTITUTE A "SALE"
UNDER THE SECURITIES ACT, PROVIDED IN EACH SUCH CASE A MINIMUM OF 1,000 SHARES
OF SERIES A PREFERRED STOCK IS HELD BY EACH SUBSEQUENT HOLDER.

         Every stock certificate representing Common Stock issued upon
conversion of a share of Series A Preferred Stock shall bear a legend in
substantially the following form, unless such Common Stock (a) has been sold
pursuant to a registration statement that has been declared effective under the
Securities Act (and which continues to be effective at the time of such
transfer), (b) can be sold by the holder thereof pursuant to Rule 144(k) under
the Securities Act without restrictions on resale provided the holder has
delivered appropriate representations required by the Company with respect to
compliance with such rule, or (c) has been issued upon conversion of Preferred
Stock that had been transferred pursuant to a registration statement that has
been declared effective under the Securities Act (and which continue to be
effective at the time of such transfer), or unless otherwise agreed by the
Corporation in writing:

THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED (THE "SECURITIES ACT"). THE HOLDER HEREOF, BY PURCHASING THIS SECURITY,
AGREES FOR THE BENEFIT OF THE CORPORATION THAT THIS SECURITY MAY NOT BE RESOLD,
PLEDGED OR OTHERWISE TRANSFERRED OTHER THAN (1) TO THE CORPORATION, (2) IN AN
OFFSHORE TRANSACTION (AS DEFINED IN REGULATION S UNDER THE SECURITIES ACT) IN


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ACCORDANCE WITH REGULATION S UNDER THE SECURITIES ACT, (3) PURSUANT TO AN
EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT PROVIDED BY RULE 144 (IF
APPLICABLE) UNDER THE SECURITIES ACT OR (4) PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN EACH CASE IN ACCORDANCE WITH
ANY APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES. THE HOLDER
HEREOF, BY PURCHASING THIS SECURITY, REPRESENTS AND AGREES FOR THE BENEFIT OF
THE CORPORATION THAT IT IS HOLDING THIS SECURITY FOR INVESTMENT PURPOSES AND NOT
FOR DISTRIBUTION. THE HOLDER HEREOF WILL NOT, DIRECTLY OR INDIRECTLY, ENGAGE IN
ANY HEDGING TRANSACTIONS WITH REGARD TO THIS SECURITY OR ANY COMMON STOCK
ISSUABLE UPON CONVERSION OF THIS SECURITY EXCEPT AS PERMITTED BY THE SECURITIES
ACT.

         The Corporation has no obligation under this Certificate to file any
registration statement covering resales of any Series A Preferred Stock, any
shares of Common Stock issuable or issued upon conversion of Series A Preferred
Stock, or any other securities.


10.      Replacement.

             Upon receipt of evidence reasonably satisfactory to the Corporation
of the ownership and the loss, theft, destruction or mutilation of any
certificate evidencing shares of Series A Preferred Stock, and in the case of
any such loss, theft or destruction, upon receipt of indemnity and a surety bond
satisfactory to the Corporation, or, in the case of any such mutilation, upon
surrender of the mutilated certificate, the Corporation shall execute and
deliver in replacement a new certificate of like kind representing the number of
shares of Series A Preferred Stock represented by the lost, stolen, destroyed or
mutilated certificate and dated the date of the lost, stolen, destroyed or
mutilated certificate.


11. Notices.

             All notices under this Certificate of Designation shall be in
writing and sent by (a) certified or registered mail, return receipt requested,
(b) a recognized overnight courier service, (c) telecopier or (d) personal
delivery. Notices to the Corporation shall be addressed to the Corporation's
chief executive officer at the Corporation's principal executive offices, and
notices to any holder shall be addressed to such holder's address in the records
of the Corporation. Any notice shall be deemed duly given (x) in the case of a
notice sent other than by mail, on the date actually delivered at such addressed
(evidenced, in the case of delivery by courier or other delivery service, by
confirmation of delivery from the service making the delivery or, in the case of
a notice sent by telecopier, by receipt of a transmission confirmation form or
the addressee's confirmation of receipt), and (y) in the case of any notice sent
by mail, on the third Business Day following deposit in the U.S. mails with
first-class postage prepaid.


12. Definitions.

     12.1. "Accumulation Rate" means two-and-a-half percent (2.5%).

     12.2. "Business Day" means any day other than a Saturday or Sunday or a day
on which commercial banking institutions in Boston, Massachusetts or New York,
New York are authorized by law to be closed. Any reference to "days" (unless
Business Days are specified) shall mean calendar days.

     12.3. "Change of Control" shall mean any consolidation, merger, issuance of
capital stock, sale of all or substantially all the assets of the Corporation or
similar transaction to which the Corporation is a party (whether in a single
transaction or series of related transactions) in which the stockholders of the
Corporation immediately prior to such event do not own, directly or indirectly,


                                       13


a majority of the outstanding voting power of the surviving corporation or
acquiring entity, as the case may be, received in respect of their Corporation
shares, immediately after such event.

     12.4. "Corporate Change" shall mean any capital reorganization,
reclassification, consolidation, merger or sale of all or substantially all of
the Corporation's assets to another Person which is effected in such a way that
holders of Common Stock are entitled to receive (either directly or upon a
subsequent liquidation of the Corporation) securities or assets in respect of or
in exchange for Common Stock.

     12.5. "Current Market Price" shall mean on any date specified herein (a)
with respect to any securities, the average daily Market Price during the period
of the most recent 10 trading days, ending on such date, except that if such
securities are not then listed or admitted to trading on any national securities
exchange or quoted in the over-the-counter market, the Current Market Price
shall be the Market Price on such date, and (b) with respect to any property
other than securities, the fair value thereof on such date as reasonably
determined in good faith by the Board of Directors of the Corporation as of the
date on which the determination is to be made.

     12.6. "Market Price" shall mean on any date specified herein with respect
to securities issued by any Person, the amount per share or other applicable
unit of such securities equal to (a) the last sale price of such securities,
regular way, at the end of regular market trading on such date or, if no such
sale takes place on such date, the average of the closing bid and asked prices
thereof at the end of regular market trading on such date, in each case as
officially reported on the principal national securities exchange on which such
securities are then listed or admitted to trading; or (b) if such securities are
not then listed or admitted to trading on any national securities exchange but
are designated as a national market system security by the NASD, the last
trading price of such securities at the end of regular market trading on such
date, or (c) if there shall have been no trading on such date or if such
securities are not so designated, the average of the closing bid and asked
prices of such securities at the end of regular market trading on such date as
shown by the NASD automated quotation system, or (d) if such securities are not
then listed or admitted to trading on any national exchange or quoted in the
over-the-counter market, the fair value thereof on such date as reasonably
determined in good faith by the Board of Directors of the Corporation as of the
date on which the determination is to be made.

     12.7. "NASD" shall mean the National Association of Securities Dealers,
Inc.

     12.8. "Person" shall mean an individual, partnership, corporation, limited
liability company, association, trust, unincorporated organization or other
entity.

     12.9. "Preference Amount" shall mean with respect to each share of
Preferred Stock the sum of (a) $1,000.00 plus (b) all accrued and unpaid
dividends on such share.


                                       14



     ANTIGENICS INC. has caused this Certificate of Designation to be signed by
Garo Armen, its Chairman and Chief Executive Officer, and attested by Claudia
Wernick, an Assistant Secretary, this 24th day of September 2003.



                                 /s/ Garo Armen
                                 ------------------------------------
                                 Garo Armen
                                 Chairman and Chief Executive Officer


ATTEST:



/s/ Claudia Wernick
- -------------------
Claudia Wernick
Assistant Secretary








                                    EXHIBIT A

                                 ANTIGENICS INC

                               Conversion Notice

                      Series A Convertible Preferred Stock

         Reference is made to the Certificate of Designation, Preferences and
Rights (the "Certificate of Designation") of the Series A Convertible Preferred
Stock, face amount $1,000 per share (the "Preferred Stock"), of Antigenics Inc.,
a Delaware corporation (the "Corporation").

         In accordance with and pursuant to the Certificate of Designation, the
undersigned hereby elects to convert the number of shares of Preferred Stock
indicated below into shares of Common Stock, par value $0.01 per share (the
"Common Stock"), of the Corporation, by tendering the stock certificate(s)
representing the share(s) of Preferred Stock specified below as of the date
specified below.

       Date of Conversion:
                            -----------------------------------------

       Number of shares of Preferred Stock to be converted:               shares
                                                             -------------

       Stock certificate no(s). of shares of Preferred Stock to be converted:

                                                      --------------------------


         Please confirm the following information:

                  Conversion Value: $
                                     -------------------------------------------

                  Number of shares of Common Stock to be issued:          shares
                                                                 ---------

         Please issue the Common Stock and, if applicable, any check drawn on an
account of the Corporation, in the following name and to the following address:

                  Name of holder of Common Stock:
                                                    ----------------------------


                  Address of holder:
                                                     ---------------------------





                  Facsimile Number:
                                                     ---------------------------



                                       16




The holder represents hereby to the Corporation that he/she/it [ ] is [ ]
is not (and has not been during the preceding three months) an "affiliate" of
the Corporation as such term is defined in Rule 144(a) promulgated under the
Securities Act of 1933, as amended.


                           AUTHORIZATION:


                           By:
                               -------------------------------------------------
                           Signature of preferred stockholder, exactly as it
                           appears on stock certificate

                           Name (print):

                           Title:


                           Dated:
                                  ----------------------------


ACKNOWLEDGED AND AGREED:


ANTIGENICS INC.


By:
    -------------------------------------------------------------------

Name:

Title:


                                       17