New York _ People who picture vaccination as a way of wardingoff childhood diseases have another image coming. Some 360cancer immunologists and allied scientists from 16 countries haveconverged here for Cancer Vaccine 1994, the first internationalsymposium on cancer vaccines. The three-day gathering issponsored by the Cancer Research Institute here, and co-sponsoredby a clutch of charitable foundations and biotechnology companies.The latter include Cytel Corp., Somatix Therapy Corp., ImmunexCorp. and Amgen Inc.Sir Walter Bodmer, the geneticist and director-general of Britain'sImperial Cancer Research Fund, chaired a session Monday devotedto tumor antigens. In an interview with BioWorld Today, Bodmersounded an upbeat note. "There is a background of increasingoptimism for the opportunity of new therapy, and maybe evenpreventive vaccination, based on our knowledge of the immunesystem, " Bodmer said.Immunotherapy will come a lot sooner than prophylactic vaccines,Bodmer said. "You could almost argue that prevention ispotentially easier than therapy," he said. "With the latter, youalways start too late. You're always having to do the Phase Iexperiments in late-stage cancers. By which time, it's probablyalready escaped from immune responses."True vaccination," Bodmer said, "is a fascinating possibility, butmay be very difficult to actually test. Can you vaccinate peopleagainst the ras oncogene, p53 and perhaps the colon polyposis genemutation? And can you do that without damage?" he askedrhetorically, adding, "And can you then detect the loss of the tumoroutput?"Organic chemist Donald Hunt, of the University of Virginia atCharlottesville, demonstrated a technology based on spectroscopyand chromatography that detected a lengthy melanoma tumorsurface antigen among 10,000 peptides. It derives from a proteinpresent on the tumor but not on normal melanocytes. "Cytotoxic Tcells from six different patients all recognize this peptide," Hunttold the session, "and triggered an immune response that killed thetumor."He later told BioWorld Today, "If we can find some way ofintroducing this protein into a vaccine, it is quite reasonable andpossible, but not a sure thing, that we will be able to vaccinatepeople against melanoma _ both therapeutically and preventively."Hunt's "remarkable technology," as Bodmer called it, sifts throughthe 10,000 peptides with which a cell studs its surface to signal theimmune system to hold off because it is "self." When a pathogeninvades the cell, it generates its own impostor surface peptides, butin minuscule numbers, say five or six. Hunt's instrumentation picksthese out and determines their amino-acid sequence with sensitivityin the femtomole range. This, he said, "is 100 to 1,000 times moresensitive than any other methodology in the world." Hunt added,"So it's applicable across the biotechnology scheme of things toproteins and peptides, and works on impure samples."Moreover, he asserted, the system can generate not only tumorantigens, but vaccine targets for infectious diseases; he mentionedAIDS and malaria as examples.Hunt and faculty colleague, V.H. Engelhard, have joined forceswith the Chicago firm Receptor Laboratories to set up a commerciallaboratory in Charlottesville. They formed their company in May,and expect to go into business at the beginning of 1995.Not only will he and his university partner remain on faculty, Huntsaid, "what's unique about it is that anything we discover in ouracademic labs gets patented by the University of Virginia andlicensed out to our company. And anything discovered in ourindustrial lab counterpart also gets patented by the University ofVirginia and licensed back to our company."So the partners are now "in the process of collaborating withpharmaceutical industries to try to identify peptide antigens on thesurface of cells that could possibly be vaccines against a variety oftumors."Research immunologist Lloyd Olds is convenor of the CancerVaccine 1994 event and world director of the Ludwig Institute forCancer Research, also in New York.Opening the first plenary session, he told the audience, "In the past,tumor immunology has been criticized as a field that has notadvanced much beyond the phenomenological phase, and wherepromises have been oversold and overbought. Now that we enterthe era of structurally defined tumor antigens and the clinical testingof specific cancer vaccines, we have the opportunity to see whetherthe sustained optimism of tumor immunologists turns out to havebeen justified." n

-- David Leff Science Editor

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