Exhibit 10.5
                                CYTEL CORPORATION

                                 1989 STOCK PLAN
                                 ---------------

                    As Amended and Restated October 11, 1991
                          and Amended December 4, 1992,
                 March 19, 1993, March 18, 1994, March 15, 1996,
              September 20, 1996, March 12, 1998 and June 12, 1998

1.       PURPOSE.

         (a) The purpose of the Plan is to provide a means by which selected
employees and directors of and advisors and consultants to Cytel Corporation, a
Delaware corporation (the "Company"), and its Affiliates, as defined in
subparagraph 1(b), may be given an opportunity to benefit from increases in
value of the stock of the Company through the granting of (i) incentive stock
options, (ii) nonstatutory stock options, (iii) stock bonuses, and (iv) rights
to purchase stock, all as defined below.

         (b) The word "Affiliate" as used in the Plan means any parent
corporation or subsidiary corporation of the Company, as those terms are defined
in Sections 424(e) and (f), respectively, of the Internal Revenue Code of 1986,
as amended (the "Code").

         (c) The Company, by means of the Plan, seeks to retain the services of
persons now employed by or serving as advisors, consultants or directors to the
Company and its Affiliates, to secure and retain the services of new
employees/persons capable of filling such positions, and to provide incentives
for such persons to exert maximum efforts for the success of the Company.

         (d) The Company intends that the rights issued under the Plan ("Stock
Awards") shall, in the discretion of the Board of Directors of the Company (the
"Board") or any committee to which responsibility for administration of the Plan
has been delegated pursuant to subparagraph 2(c), be either (i) stock options
granted pursuant to paragraph 5 hereof, including incentive stock options as
that term is used in Section 422 of the Code ("Incentive Stock Options"), or
options which do not qualify as Incentive Stock Options ("Nonstatutory Stock
Options") (together hereinafter referred to as "Options"), or (ii) stock bonuses
or rights to purchase restricted stock granted pursuant to paragraph 6 hereof.
All Options shall be separately designated Incentive Stock Options or
Nonstatutory Stock Options at the time of grant, and in such form as issued
pursuant to paragraph 5, and a separate certificate or certificates shall be
issued for shares purchased on exercise of each type of Option. An Option
designated as a Nonstatutory Stock Option shall not be treated as an Incentive
Stock Option.

2.       ADMINISTRATION.

         (a) The Plan shall be administered by the Board unless and until the
Board delegates administration to a committee, as provided in subparagraph 2(c).

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         (b) The Board shall have the power, subject to, and within the
limitations of, the express provisions of the Plan:

             (i) To determine from time to time which of the persons eligible
under the Plan shall be granted Stock Awards; when and how Stock Awards shall be
granted; whether a Stock Award will be an Incentive Stock Option, a Nonstatutory
Stock Option, a stock bonus, a right to purchase restricted stock, or a
combination of the foregoing; the provisions of each Stock Award granted (which
need not be identical), including the time or times when a person shall be
permitted to purchase or receive stock pursuant to a Stock Award; and the number
of shares with respect to which Stock Awards shall be granted to each such
person.

             (ii) To construe and interpret the Plan and Stock Awards granted
under it, and to establish, amend and revoke rules and regulations for its
administration. The Board, in the exercise of this power, may correct any
defect, omission or inconsistency in the Plan or in any Stock Award, in a manner
and to the extent it shall deem necessary or expedient to make the Plan fully
effective.

             (iii) To amend the Plan as provided in paragraph 12.

             (iv) Generally, to exercise such powers and to perform such acts as
the Board deems necessary or expedient to promote the best interests of the
Company.

         (c) The Board may delegate administration of the Plan to a committee of
the Board composed of not fewer than two (2) members (the "Committee"), all of
the members of which Committee shall be non-employee directors and may also be,
in the discretion of the Board, outside directors. If administration is
delegated to a Committee, the Committee shall have, in connection with the
administration of the Plan, the powers theretofore possessed by the Board,
including the power to delegate to a subcommittee of two (2) or more Outside
Directors any of the administrative powers the Committee is authorized to
exercise (and references in this Plan to the Board shall thereafter be to the
Committee or such a subcommittee), subject, however, to such resolutions, not
inconsistent with the provisions of the Plan, as may be adopted from time to
time by the Board. The Board may abolish the Committee at any time and revest in
the Board the administration of the Plan.

         (d) (i) The term "non-employee director," as used in this Plan, shall
mean a director who either (A) is not a current employee or officer (as defined
for purposes of Section 16 of the Securities Exchange Act of 1934, as amended
(the "Exchange Act")) of the Company or its parent or subsidiary, does not
receive compensation (directly or indirectly) from the Company or its parent or
subsidiary for services rendered as a consultant or in any capacity other than
as a director (except for an amount as to which disclosure would not be required
under Item 404(a) of Regulation S-K ("Regulation S-K") promulgated pursuant to
the Securities Act of 1933 (the "Securities Act")), does not possess an interest
in any other transaction as to which disclosure would be required under Item
404(a) of Regulation S-K, and is not engaged in a business relationship as to
which disclosure would be required under Item 404(b) of Regulation S-K; or (B)
is otherwise considered a "non-employee director" for purposes of Rule 16b-3.

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             (ii) The term "outside director," as used in this Plan shall mean a
director who either (A) is not a current employee of the Company or an
"affiliated corporation" (within the meaning of the Treasury regulations
promulgated under Section 162(m) of the Code), is not a former employee of the
Company or an "affiliated corporation" receiving compensation for prior services
(other than benefits under a tax qualified pension plan), was not an officer of
the Company or an "affiliated corporation" at any time, and is not currently
receiving direct or indirect remuneration from the Company or an "affiliated
corporation" for services in any capacity other than as a director, or (B) is
otherwise considered an "outside director" for purposes of Section 162(m) of the
Code.

         (e) Any requirement that an administrator of the Plan be a
"non-employee director" shall not apply if the Board or the Committee expressly
declares that such requirement shall not apply.

         (f) Notwithstanding anything in this Section 2 to the contrary, the
Board or Committee may delegate to a committee of one or more members of the
Board the authority to grant options to persons not subject to the requirements
of Section 16 of the Exchange Act.

3.       SHARES SUBJECT TO THE PLAN.

         (a) Subject to the provisions of paragraph 11 relating to adjustments
upon changes in stock, the stock that may be issued pursuant to Stock Awards
granted under the Plan shall not exceed in the aggregate seven million seven
hundred fifty thousand (7,750,000) shares of the Company's common stock less the
number of shares of the Company's common stock which has been sold under, or may
be sold pursuant to outstanding options granted under, the Company's 1994
Non-Employee Directors' Stock Option Plan. If any Stock Award granted under the
Plan shall for any reason expire or otherwise terminate without having been
exercised in full, the stock not purchased under such Stock Award shall again
become available for the Plan.

         (b) The stock subject to the Plan may be unissued shares or reacquired
shares, bought on the market or otherwise.

         (c) An Incentive Stock Option may be granted to an eligible person
under the Plan only if the aggregate fair market value (determined at the time
the Option is granted) of the stock with respect to which incentive stock
options (as defined in the Code) granted after 1986 are exercisable for the
first time by such optionee during any calendar year under all incentive stock
option plans of the Company and its Affiliates does not exceed one hundred
thousand dollars ($100,000). If it is determined that an entire Option or any
portion thereof does not qualify for treatment as an Incentive Stock Option by
reason of exceeding such maximum, such Option or the applicable portion shall be
considered a Nonstatutory Stock Option.

4.       ELIGIBILITY.

         (a) Incentive Stock Options may be granted only to employees (including
officers) of the Company or its Affiliates. A director of the Company shall not
be eligible to receive Incentive Stock Options unless such director is also an
employee (including an officer) of the Company or any Affiliate. Stock Awards
other than Incentive Stock Options may be granted only to employees (including
officers) or directors of or advisors or consultants to the Company or its
Affiliates.

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         (b) No person shall be eligible for the grant of an Incentive Stock
Option under the Plan if, at the time of grant, such person owns (or is deemed
to own pursuant to Section 424(d) of the Code) stock possessing more than ten
percent (10%) of the total combined voting power of all classes of stock of the
Company or of any of its Affiliates unless the exercise price of such Option is
at least one hundred ten percent (110%) of the fair market value of such stock
at the date of grant and the term of such Option does not exceed five (5) years
from the date of grant.

         (c) In any calendar year, no person shall be eligible to be granted
Incentive Stock and Nonstatutory Stock Options under the Plan covering an
aggregate number of shares of the Company's common stock greater than nine
hundred fifty thousand (950,000) shares.

5.       OPTION PROVISIONS.

     Each Option shall be in such form and shall contain such terms and
conditions as the Board or the Committee shall deem appropriate. The provisions
of separate Options need not be identical, but each Option shall include
(through incorporation of provisions hereof by reference in the Option or
otherwise) the substance of each of the following provisions:

         (a) No Option shall be exercisable after the expiration of ten (10)
years from the date it was granted.

         (b) The exercise price of each Incentive Stock Option shall be not less
than one hundred percent (100%) of the fair market value of the stock subject to
the Option on the date the Option is granted. The exercise price of each
Nonstatutory Stock Option shall be not less than eighty-five percent (85%) of
the fair market value of the stock subject to the Option on the date the Option
is granted.

         (c) The purchase price of stock acquired pursuant to an Option shall be
paid, to the extent permitted by applicable statutes and regulations, either (i)
in cash at the time the Option is exercised, or (ii) at the discretion of the
Board or the Committee, either at the time of the grant or exercise of the
Option, (A) by delivery to the Company of other common stock of the Company, (B)
according to a deferred payment or other arrangement (which may include, without
limiting the generality of the foregoing, the use of other common stock of the
Company) with the person to whom the Option is granted or to whom the Option is
transferred pursuant to subparagraph 5(d), or (C) in any other form of legal
consideration that may be acceptable to the Board or the Committee.

         In the case of any deferred payment arrangement, interest shall be
payable at least annually and shall be charged at the minimum rate of interest
necessary to avoid the treatment as interest, under any applicable provisions of
the Code, of any amounts other than amounts stated to be interest under the
deferred payment arrangement.

         (d) An Incentive Stock Option shall not be transferable except by will
or by the laws of descent and distribution, and shall be exercisable during the
lifetime of the person to whom the Option is granted only by such person. A
Nonstatutory Stock Option shall only be transferable by the Optionee upon such
terms and conditions as are set forth in the Option Agreement for such
Nonstatutory Stock Option, as the Board or the Committee shall determine in its
discretion.

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         (e) The total number of shares of stock subject to an Option may, but
need not, be allotted in periodic installments (which may, but need not, be
equal). From time to time during each of such installment periods, the Option
may become exercisable ("vest") with respect to some or all of the shares
allotted to that period, and may be exercised with respect to some or all of the
shares allotted to such period and/or any prior period as to which the Option
was not fully exercised. During the remainder of the term of the Option (if its
term extends beyond the end of the installment periods), the Option may be
exercised from time to time with respect to any shares then remaining subject to
the Option. The provisions of this subparagraph 5(e) are subject to any Option
provisions governing the minimum number of shares as to which an Option may be
exercised.

         (f) The Company may require any optionee, or any person to whom an
Option is transferred under subparagraph 5(d), as a condition of exercising any
such Option, (i) to give written assurances satisfactory to the Company as to
the optionee's knowledge and experience in financial and business matters and/or
to employ a purchaser representative reasonably satisfactory to the Company who
is knowledgeable and experienced in financial and business matters, and that he
or she is capable of evaluating, alone or together with the purchaser
representative, the merits and risks of exercising the Option; and (ii) to give
written assurances satisfactory to the Company stating that such person is
acquiring the stock subject to the Option for such person's own account and not
with any present intention of selling or otherwise distributing the stock. These
requirements, and any assurances given pursuant to such requirements, shall be
inoperative if (A) the issuance of the shares upon the exercise of the Option
has been registered under a then currently effective registration statement
under the Securities Act or (B) as to any particular requirement, a
determination is made by counsel for the Company that such requirement need not
be met in the circumstances under the then applicable securities laws.

         (g) An Option shall terminate three (3) months after termination of the
optionee's employment or relationship as a advisor, consultant or director with
the Company or an Affiliate, unless (i) such termination is due to such person's
permanent and total disability, within the meaning of Section 422(c)(6) of the
Code, in which case the Option may, but need not, provide that it may be
exercised at any time within six (6) months following such termination of
employment or relationship as an advisor, consultant or director; or (ii) the
optionee dies while in the employ of or while serving as an advisor, consultant
or director to the Company or an Affiliate, or within not more than three (3)
months after termination of such relationship, in which case the Option may, but
need not, provide that it may be exercised at any time within six (6) months
following the death of the optionee by the person or persons to whom the
optionee's rights under such Option pass by will or by the laws of descent and
distribution; or (iii) the Option by its terms specifies either (A) that it
shall terminate sooner than three (3) months after termination of the optionee's
employment or relationship as an advisor, consultant or director or (B) that it
may be exercised more than three (3) months after termination of the
relationship with the Company or an Affiliate. This subparagraph 5(g) shall not
be construed to extend the term of any Option or to permit anyone to exercise
the Option after expiration of its term, nor shall it be construed to increase
the number of shares as to which any Option is exercisable from the amount
exercisable on the date of termination of the optionee's employment or
relationship as an advisor, consultant or director.

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         (h) The Option may, but need not, include a provision whereby the
optionee may elect at any time during the term of his or her employment or
relationship as an advisor, consultant or director with the Company or any
Affiliate to exercise the Option as to any part or all of the shares subject to
the Option prior to the stated vesting date of the Option or of any installment
or installments specified in the Option. Any shares so purchased from any
unvested installment or Option may be subject to a repurchase right in favor of
the Company or to any other restriction the Board or the Committee determines to
be appropriate.

         (i) To the extent provided by the terms of an Option, the optionee may
satisfy any federal, state or local tax withholding obligation relating to the
exercise of such Option by any of the following means or by a combination of
such means: (i) tendering a cash payment; (ii) authorizing the Company to
withhold from the shares of the common stock otherwise issuable to the
participant as a result of the exercise of the Option a number of shares having
a fair market value less than or equal to the amount of the withholding tax
obligation; or (iii) delivering to the Company owned and unencumbered shares of
the common stock having a fair market value less than or equal to the amount of
the withholding tax obligation.

6.       TERMS OF STOCK BONUSES AND PURCHASES OF RESTRICTED STOCK.

     Each stock bonus or restricted stock purchase agreement shall be in such
form and shall contain such terms and conditions as the Board or the Committee
shall deem appropriate. The terms and conditions of stock bonus or restricted
stock purchase agreements may change from time to time, and the terms and
conditions of separate agreements need not be identical, but each stock bonus or
restricted stock purchase agreement shall include (through incorporation of
provisions hereof by reference in the agreement or otherwise) the substance of
each of the following provisions as appropriate:

         (a) The purchase price under each stock purchase agreement shall be
such amount as the Board or Committee shall determine and designate in such
agreement. Notwithstanding the foregoing, the Board or the Committee may
determine that eligible participants in the Plan may be awarded stock pursuant
to a stock bonus agreement in consideration for past services actually rendered
to the Company or for its benefit.

         (b) No rights under a stock bonus or restricted stock purchase
agreement shall be assignable by any participant under the Plan, either
voluntarily or by operation of law, except where such assignment is required by
law or expressly authorized by the terms of the applicable stock bonus or
restricted stock purchase agreement.

         (c) The purchase price of stock acquired pursuant to a stock purchase
agreement shall be paid either: (i) in cash at the time of purchase; (ii) at the
discretion of the Board or the Committee, according to a deferred payment or
other arrangement with the person to whom the stock is sold; or (iii) in any
other form of legal consideration that may be acceptable to the Board or the
Committee in their discretion. Notwithstanding the foregoing, the Board or the
Committee to which administration of the Plan has been delegated may award stock
pursuant to a stock bonus agreement in consideration for past services actually
rendered to the Company or for its benefit.

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         (d) Shares of stock sold or awarded under the Plan may, but need not,
be subject to a repurchase option in favor of the Company in accordance with a
vesting schedule to be determined by the Board or the Committee.

         (e) In the event a person ceases to be an employee of or ceases to
serve as an advisor, consultant or director to the Company or an Affiliate, the
Company may repurchase or otherwise reacquire any or all of the shares of stock
held by that person which have not vested as of the date of termination under
the terms of the stock bonus or restricted stock purchase agreement between the
Company and such person.

7.       COVENANTS OF THE COMPANY.

         (a) During the terms of the Stock Awards granted under the Plan, the
Company shall keep available at all times the number of shares of stock required
to satisfy such Stock Awards.

         (b) The Company shall seek to obtain from each regulatory commission or
agency having jurisdiction over the Plan such authority as may be required to
issue and sell shares of stock under the Stock Awards granted under the Plan;
provided, however, that this undertaking shall not require the Company to
register under the Securities Act either the Plan, any Stock Award granted under
the Plan or any stock issued or issuable pursuant to any such Stock Award. If,
after reasonable efforts, the Company is unable to obtain from any such
regulatory commission or agency the authority which counsel for the Company
deems necessary for the lawful issuance and sale of stock under the Plan, the
Company shall be relieved from any liability for failure to issue and sell stock
upon exercise of such Stock Awards unless and until such authority is obtained.

8.       USE OF PROCEEDS FROM STOCK.

     Proceeds from the sale of stock pursuant to Stock Awards granted under the
Plan shall constitute general funds of the Company.

9.       MISCELLANEOUS.

         (a) The Board or the Committee shall have the power to accelerate the
time during which a Stock Award may be exercised or the time during which a
Stock Award or any part thereof will vest, notwithstanding the provisions in the
Stock Award stating the time during which it may be exercised or the time during
which it will vest.

         (b) Neither an optionee nor any person to whom an Option is transferred
under subparagraph 5(d) shall be deemed to be the holder of, or to have any of
the rights of a holder with respect to, any shares subject to such Option unless
and until such person has satisfied all requirements for exercise of the Option
pursuant to its terms.

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         (c) Throughout the term of any Option granted pursuant to the Plan, the
Company shall make available to the holder of such Option, not later than one
hundred twenty (120) days after the close of each of the Company's fiscal years
during the Option term, upon request, such financial and other information
regarding the Company as comprises the annual report to the stockholders of the
Company provided for in the bylaws of the Company.

         (d) Nothing in the Plan or any instrument executed or Stock Award
granted pursuant thereto shall confer upon any eligible employee, advisor,
consultant, director or holder of Stock Awards under the Plan any right to
continue in the employ of the Company or any Affiliate (or to continue acting as
an advisor, consultant or director) or shall affect the right of the Company or
any Affiliate to terminate the employment or consulting relationship or
directorship of any eligible employee, advisor, consultant, director or holder
of Stock Awards under the Plan with or without cause. In the event that a holder
of Stock Awards is permitted or otherwise entitled to take a leave of absence,
the Company shall have the unilateral right to (i) determine whether such leave
of absence will be treated as a termination of employment or relationship as
advisor, consultant or director for purposes of paragraphs 5(g) or 6(e) hereof
and corresponding provisions of any outstanding Stock Awards, and (ii) suspend
or otherwise delay the time or times at which exercisability or vesting would
otherwise occur with respect to any outstanding Stock Awards under the Plan.

10.      CANCELLATION AND RE-GRANT OF OPTIONS.

         (a) The Board or the Committee shall have the authority to effect, at
any time and from time to time, with the consent of the affected optionees, (i)
the repricing of any or all outstanding Options under the Plan and/or (ii) the
cancellation of any or all outstanding Options under the Plan and the grant in
substitution therefor of new Options under the Plan covering the same or
different numbers of shares of common stock, but having an exercise price per
share not less than eighty-five percent (85%) of the fair market value (one
hundred percent (100%) of the fair market value in the case of an Incentive
Stock Option or, in the case of a 10% stockholder (as defined in subparagraph
4(c)), not less than one hundred and ten percent (110%) of the fair market value
per share of common stock on the new grant date.

         (b) Shares subject to an option canceled under this Section 10 shall
continue to be counted against the maximum award of options permitted to be
granted to any person pursuant to subsection 4(c) of the Plan. The repricing of
an option under this Section 10, resulting in a reduction of the exercise price,
shall be deemed to be a cancellation of the original option and the grant of a
substitute option; in the event of such repricing, both the original and the
substituted options shall be counted against the maximum awards of options
permitted to be granted to any person pursuant to subsection 4(c) of the Plan.
The provisions of this subsection 10(b) shall be applicable only to the extent
required by Section 162(m) of the Code.

11.      ADJUSTMENTS UPON CHANGES IN STOCK.

         (a) If any change is made in the stock subject to the Plan, or subject
to any Stock Award granted under the Plan (through merger, consolidation,
reorganization, recapitalization, stock dividend, dividend in property other
than cash, stock split, liquidating dividend, combination of shares, exchange of
shares, change in corporate structure or otherwise), the Plan and outstanding
Stock Awards will be appropriately adjusted in the class(es) and maximum number
of shares subject to the Plan and the class(es) and number of shares and price
per share of stock subject to outstanding Stock Awards.

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         (b) In the event of: (i) a dissolution or liquidation of the Company;
(ii) a merger or consolidation in which the Company is not the surviving
corporation; or (iii) a reverse merger in which the Company is the surviving
corporation but the shares of the Company's common stock outstanding immediately
preceding the merger are converted by virtue of the merger into other property,
whether in the form of securities, cash or otherwise then at the discretion of
the Board or Committee, and to the extent permitted by applicable law: (A) any
surviving corporation shall assume any Stock Awards outstanding under the Plan
or shall substitute similar Stock Awards for those outstanding under the Plan,
(B) such Stock Awards shall continue in full force and effect, or (C) respect to
Stock Awards held by persons then performing services as employees of or as
advisors, consultants or directors for the Company and its Affiliates, as the
case may be, the Company may either (1) arrange to pay a cash settlement for
such Stock Awards equal to the difference between the amount to be paid for an
equivalent amount of stock pursuant to such corporate transaction and the
exercise price under such Stock Award, or (2) accelerate the time during which
such Stock Awards become vested or may be exercised and terminate the Stock
Awards not exercised prior to such event.

12.      AMENDMENT OF THE PLAN.

         (a) The Board at any time, and from time to time, may amend the Plan.
However, except as provided in paragraph 11 relating to adjustments upon changes
in stock, no amendment shall be effective unless approved by the stockholders of
the Company within twelve (12) months before or after the adoption of the
amendment, where the amendment will:

             (i) Increase the number of shares reserved for Stock Awards under
the Plan;

             (ii) Modify the requirements as to eligibility for participation in
the Plan to the extent such modification requires stockholder approval in order
for the Plan to satisfy the requirements of Section 422(b) of the Code or to
comply with the requirements of Rule 16b-3 promulgated under the Exchange Act;
or

             (iii) Modify the Plan in any other way if such modification
requires stockholder approval in order for the Plan to satisfy the requirements
of Section 422(b) of the Code or to comply with the requirements of Rule 16b-3
promulgated under the Exchange Act.

         (b) The Board may in its sole discretion submit any other amendment to
the Plan for stockholder approval, including, but not limited to, amendments to
the Plan intended to satisfy the requirements of Section 162(m) of the Code and
the regulations promulgated thereunder regarding the exclusion of
performance-based compensation from the limit on corporate deductibility of
compensation paid to certain executive officers.

         (c) It is expressly contemplated that the Board may amend the Plan in
any respect the Board deems necessary or advisable to provide optionees with the
maximum benefits provided or to be provided under the provisions of the Code and
the regulations promulgated thereunder relating to employee Incentive Stock
Options and/or to bring the Plan and/or Incentive Stock Options granted under it
into compliance therewith.

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         (d) Rights and obligations under any Stock Award granted before
amendment of the Plan shall not be altered or impaired by any amendment of the
Plan unless (i) the Company requests the consent of the person to whom the Stock
Award was granted and (ii) such person consents in writing.

13.      TERMINATION OR SUSPENSION OF THE PLAN.

         (a) The Board may suspend or terminate the Plan at any time. Unless
sooner terminated, the Plan shall terminate on December 31, 2000. No Stock
Awards may be granted under the Plan while the Plan is suspended or after it is
terminated.

         (b) Rights and obligations under any Stock Award granted while the Plan
is in effect shall not be altered or impaired by suspension or termination of
the Plan, except with the consent of the person to whom the Stock Award was
granted.

14.      EFFECTIVE DATE OF PLAN.

     The Plan shall become effective as determined by the Board, but no Stock
Awards granted under the Plan shall be exercisable unless and until the Plan has
been approved by the stockholders of the Company, and, if required, an
appropriate permit has been issued by the Commissioner of Corporations of the
State of California.