Subject: Progress Is Seen Toward Vaccine For Aids Strains 
Date: Published: 12/14/90 (64 lines)
Source: Wall Street Journal. Copyright Dow Jones & Co. Inc.

    Technology & Health:
    Progress Is Seen
    Toward Vaccine
    For Aids Strains
    ----
    By Marilyn Chase
    Staff Reporter of The Wall Street Journal

    In a series of lab experiments, scientists raised hope
 that a vaccine useful against the highly variable strains of
 the AIDS virus could be created.
    For years, a number of vaccine researchers have worked
 with a portion of the virus's outer coat, called the V3 loop,
 which is believed likely to spark a strong immune response.
 This loop sits on a portion of the viral coat that tends to
 vary with each virus sample, posing a daunting challenge for
 scientists.
    Recently, however, scientists pinpointed a part of the
 loop that remained constant and unchanged in 60% of 245
 different virus samples. This common denominator, a chain of
 amino acids, may be a good candidate for a broadly useful
 vaccine, the scientists suggested.
    Moreover, when laboratory animals were vaccinated with a
 synthetic version of this protein, they produced antibodies
 that successfully neutralized or deactivated two widely
 divergent strains of the deadly virus.
    This action, known as cross-neutralization, is a kind of
 holy grail of AIDS vaccine development. More commonly, early
 vaccine prototypes have elicited an immune response to only
 one strain of the virus and thus cannot offer people the
 broad and effective protection against infection by any of
 the random strains of the AIDS virus to which they might be
 exposed in a real-life situation.
    The work was conducted by Kashi Javaherian of Repligen
 Corp., Cambridge, Mass., and Thomas J. Matthews of Duke
 University, Durham, N.C., and their colleagues. A report on
 their work is published in the current issue of the journal
 Science.
    Other scientists in the field of AIDS vaccine development
 said the work consolidates prior advances made by the
 Repligen-Duke team.
    "It's fair to say that this could be an important part of
 a vaccine," said Phillip W. Berman, senior scientist at
 Genentech Inc., South San Francisco.
    He offered two caveats, however. "Can you really reliably
 target antibodies to one site?" he asked. "And even if you
 can, it's been shown that viruses mutate to escape. Some of
 these mutations occur outside the loop (portion of the virus
 outer coat), suggesting you may need to elicit antibodies to
 more than just the loop."
    The authors of the study acknowledged the problem created
 by the AIDS virus evolving "resistant mutants" or "escape
 variants" to help it elude the body's immune-defense system.
 Thus, they said the next challenge will be to find out
 whether such mutants can be neutralized as well.

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