Subject: Report of Further Step In Developing an Animal AIDS Vaccine 
Date: Published: 12/8/89 (91 lines)
Source:  Wall Street Journal.  Copyright Dow Jones & Co. Inc. 

    Technology & Medicine:
    Tulane Researchers Report Further Step
    In Developing an Animal AIDS Vaccine
    ----
    By Marilyn Chase
    Staff Reporter of The Wall Street Journal

    A team of scientists at Tulane University reported a
 further step in the development of an animal vaccine against
 acquired immune deficiency syndrome.
    The Tulane team said that eight out of nine monkeys
 vaccinated with the killed simian AIDS virus and given
 booster injections were protected against infection,
 remaining healthy and virus-free.  A ninth monkey showed signs
 of infection despite being vaccinated and receiving booster
 injections.  A group of 17 unvaccinated control animals
 exposed to the virus all became infected, with 12 dying of
 immunodeficiency.
    The report, by Michael Murphey-Corb of Tulane University
 and her colleagues is contained in this week's issue of the
 journal Science.  Their study of a whole killed virus vaccine
 follows reports by Ronald Desrosiers and others of successful
 animal vaccine experiments using whole killed virus vaccines.
 The Murphey-Corb team used formalin to kill the virus, while
 the Desrosiers team used a detergent.
    The report is important, not for its immediate application
 to humans, but because it adds hope to the field of vaccine
 research -- a field clouded by enormous technical
 difficulties.  Until this year, most vaccine researchers
 focused their attention on the use of synthetic proteins or
 gene-spliced fragments of the virus to spark immunity.  Most
 experiments in nearly a decade of work have failed to spark
 protective immunity against lethal immunodeficiency; that now
 may be changing.
    The report also adds to the credence now being given to a
 possible return to at least the experimental concept of whole
 killed vaccine.  Use of a whole AIDS virus vaccine as a
 preventative in uninfected people is generally deemed far too
 risky due to the danger that people might become infected by
 accidentally receiving an injection of live virus.  But its
 success in animals may be giving the idea a new lease on
 life.
    "The pessimism shadowing the development of an AIDS
 vaccine is showing some signs of receding," commented Dani
 Bolognesi, a Duke University AIDS researcher, in a guest
 editorial in the same issue of Science.  He said he was
 heartened by the monkey studies of Ms. Murphey-Corb and Mr. 
 Desrosiers, as well as experiments in horses by Ronald
 Montelaro.
    He also cited the use of whole killed vaccine by polio
 pioneer Jonas Salk, who reported at the AIDS Conference in
 Montreal last June that whole killed vaccine administered to
 infected chimps had possibly cleared the virus from their
 blood.  Similar studies by Dr. Salk using injections of killed
 virus as "immunotherapy" to spark immune defense in already
 infected men are ongoing.
    Despite success of the Tulane group, an earlier experiment
 reported in the same publication, in which monkeys received
 only a single dose, was inconclusive.  Still, the report
 maintains the success of the killed virus plus booster gives
 strong evidence that immunization can be of practical use in
 the development of a vaccine for use in humans.  The Tulane
 study was done by scientists at the Delta Regional Primate
 Research Center of the university, located in Covington, La.
    Scientists cautiously cheered the new results, but said
 many challenges remain before the success can be translated
 into practical benefits for people.
    "We can apparently induce protective immunity.  However,
 there are still very large challenges to deal with -- strain
 variation for instance," said Paul Luciw, a vaccine
 researcher at University of California at Davis.  Both the
 Murphey-Corb and Desrosiers experiments involved animals
 exposed to the same strain of virus with which they had been
 vaccinated, he noted.  "That's not a real-world situation."
    "Another challenge is finding procedures that will
 reliably kill the virus vaccine," he said.  "What measurements
 do you use?  There will always be a certain probability --
 however small -- of live virus coming through.  That's a
 serious limitation to this."
    "Perhaps with recombinant DNA technology, we can come up
 with the right combination of viral proteins to mimic the
 effect of this killed virus vaccine," he said.

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