Anti-AIDS Protein Developed
WASHINGTON (AP) _ In work that could lead to a possible vaccine to prevent AIDS, researchers have developed a synthetic protein that causes animals to produce antibodies to the virus that causes the deadly disease.
The scientists said Thursday it is too early to say if the antibody response would protect animals from infection by the virus that causes AIDS - acquired immune deficiency syndrome - or if this approach ultimately would be protective in humans.
If a prototype vaccine using a synthetic stimulus prove successful, however, it could have certain advantages over vaccines made from actual viral proteins, they said.
In a report to be published Friday in the journal Science, researchers at the Southwest Foundation for Biomedical Research in San Antonio, Texas, and the Harvard School of Public Health in Boston said they chemically synthesized a critical part of the protein coat that covers the AIDS virus.
When this protein was injected into rabbits, the animals developed high levels of antibodies that reacted with the AIDS virus, alternately called HTLV-3 or LAV. When these animal antibodies were tested against blood serum from five human AIDS patients, they reacted with the AIDS sera much more strongly than with fluids from normal controls, said the report.
AIDS is a fatal disease that destroys much of the body’s immune system, making it unable to resist infection and other disease. Most victims have been promiscuous male homosexuals, hemophiliacs and others using infected blood products and intravenous drug abusers.
As of March 10, it had struck 18,070 people in the United States and claimed 9,591 lives. No one is known to have recovered from the disease.
Drs. Ronald C. Kennedy and Gordon R. Dreesman of the Southwest Foundation said in a telephone interview that work done after submitting the report indicates the antibodies react very well with many variations of the often- changing AIDS virus.
″We have no indication at this point whether antibodies produced by the synthetic peptide are protective,″ said Dreesman, chairman of virology and immunology at the research center.
The next steps are to see if the rabbit antibodies neutralize the virus and then test the synthetic protein in chimpanzees, the only other primate that can contract AIDS from the human disease virus, he said. The ape tests would involve inoculating the animals with the peptide and then challenging them with live virus.
The AIDS virus is so infectious and unpredictable that scientists are not using the traditional approach to vaccines of inoculating animals or humans with weakened or killed strains of the virus in order to invoke immunity.
Instead, numerous research groups are working with all or parts of the non- pathogenic viral protein coat because tests show that these proteins also stimulate immune responses. A number of prototype vaccines made from these surface proteins are being tested on animals.
Kennedy said that if a vaccine is developed from one of these natural proteins, scientists would have to use genetic engineering to produce organisms that could make the proteins in large quantities. Proteins produced this way often are accompanied by a lot of impurities and other substances that must be removed.
″Making a synthetic vaccine would probably be more economical and much easier to purify than a recombinant (genetically engineered) vaccine,″ Kennedy said.
Others who worked on the synthetic peptide report include Dr. Richard D. Henkel and Daniel Pauletti of the Southwest Foundation, and Drs. Jonathan E. Allan, Tun-Hou Lee and Myron Essex of Harvard.