Epimmune and Cytel Combination Announced At Goldman Sachs Conference.

LAGUNA NIGUEL, Calif.--(BW HealthWire)--June 15, 1999--

Cytel Corp. (Nasdaq:CYTL) announced today at the 20th Annual Goldman Sachs Healthcare Conference that it will merge with its majority-owned subsidiary, Epimmune Inc., and rename the company Epimmune Inc.

The company will trade on Nasdaq under the symbol "EPMN" after completing the merger, anticipated to be June 30, 1999. The company will focus on building and realizing value from Epimmune's proprietary vaccine technology.

"At this point in time, all of Cytel's research and development activities are being carried out by Epimmune," said Howard E. (Ted) Greene, Cytel's chairman of the board of directors. "Because our energies are now focused on the Epimmune vaccine technology, we have decided to simplify our corporate structure and adopt the Epimmune name."

"After the combination, the current shareholders of Cytel will retain the same stake in the Company as they now hold indirectly in the subsidiary, which is about 67%," continued Greene. "The remainder will be held by Searle and Epimmune employees, as they together hold about 33% of Epimmune shares." Cytel will issue approximately 2.4 million shares of common and preferred stock to acquire the Epimmune shares it does not currently own and then will have approximately 7.4 million shares outstanding, assuming conversion of the preferred stock.

The management team will consist of Deborah A. Schueren, President and Chief Executive Officer; Robert W. Chesnut, Ph.D., Executive Vice President, Research and Development; Alessandro D. Sette, Ph.D., Vice President, Chief Scientific Officer; Mark J. Newman, Ph.D., Vice President, Infectious Disease Program; Peter C. Wulff, Vice President, Finance; John D. Fikes, Ph.D., Director, Cancer Program; and Timothy J. Lithgow, M.D., J.D., Director, Intellectual Property.

The Board of Directors will consist of Howard E. (Ted) Greene, Chairman and a founder of Cytel and several other medical technology companies; William T. Comer, Ph.D., President and CEO of SIBIA Neurosciences, Inc.; Nancy D. Rasmussen, Vice President, U.S. Marketing of G.D. Searle & Co.; Deborah A. Schueren, President and CEO of Epimmune Inc.; and Nicole Vitullo, Managing Director of Domain Associates.

"This is an exciting time for Epimmune," commented Deborah Schueren. "We have a productive collaboration with G.D. Searle in the cancer field with product candidates advancing according to our joint program plan. We have established collaborations with a number of leading investigators and are advancing the development of EpiGene(TM) vaccines for hepatitis C, hepatitis B, HIV and malaria. And our cash position is sufficient to achieve our development objectives for the next couple of years."

Epimmune is a leader in the field of T-cell recognition and activation, with nearly 30 patents and more than 150 pending applications covering its proprietary EIS(TM), EpiGene(TM) and PADRE(TM) technologies. -0-

     --  The Epitope Identification System (EIS(TM)) is Epimmune's
         proprietary platform that enables the identification and
         validation of T-cell epitopes from any protein or gene
         sequence.
     --  The EpiGene vaccine construct contains a DNA vector encoding
         a "designer antigen," which includes select epitope sequences
         from multiple antigens of the target disease. EpiGene
         vaccines are designed to elicit a broad array of conserved
         helper and cytotoxic T-cells to seek out and destroy diseased
         cells.
     --  PADRE is a family of proprietary molecules that are potent,
         synthetic, "universal" T-helper epitopes. When combined with
         antigens, PADRE induces important "co-stimulatory" signals
         which potentiate antigen-specific immune responses.

The company is applying this expertise to the development of novel vaccines for infectious diseases and cancer. In the cancer field, Epimmune is collaborating with G.D. Searle & Co., a wholly-owned subsidiary of Monsanto Co., to develop immune stimulating products for the treatment of breast, colon and lung cancer. Epimmune is also pursuing development of therapeutic vaccines for hepatitis B, hepatitis C and HIV, and prophylactic vaccines for hepatitis C, HIV and malaria.

For more information please visit our Web site at www.epimmune.com.

This press release includes forward-looking statements that reflect management's current views of future events. Actual results may differ materially from the above forward-looking statements due to a number of important factors, including but not limited to the risks associated with the enforcement of patent rights, the company's ability to develop vaccines using epitopes, the achievement of research and development objectives by the company and any collaborator, the timing and cost of conducting human clinical trials, the regulatory approval process, and the possibility that testing may reveal undesirable and unintended side effects or other characteristics that may prevent or limit the commercial use of proposed products. These factors are more fully discussed in Cytel's most recent Forms 10-K and 10-Q. The proposed combination of Cytel and Epimmune is subject to satisfaction of a number of conditions, including the negotiation and signature of definitive agreements, and there can be no assurance that the transaction will be completed by the target closing date, if at all, or that, if completed, that the combination will be successful.