AIDS research yields hormonal look-alike.AIDS research yields hormonal look-alike Antibodies against a human hormone that stimulates the immune system immune system Cells, cell products, organs, and structures of the body involved in the detection and destruction of foreign invaders, such as bacteria, viruses, and cancer cells. Immunity is based on the system's ability to launch a defense against such invaders. also inhibit test-tube replication of the virus associated with AIDS, report researchers from the National Cancer Institute in Bethesda, Md., and George Washington University George Washington University, at Washington, D.C.; coeducational; chartered 1821 as Columbian College (one of the first nonsectarian colleges), opened 1822, became a university in 1873, renamed 1904. in Washington, D.C. Why antibodies to the hormone would work against the AIDS virus AIDS virus n. See HIV. remains to be discovered, but the results suggest a new path to an AIDS vaccine AIDS vaccine A hypothetical vaccine intended to either prevent HIV infection or ensure that those infected will not fall victim to AIDS; the most promising vaccine is that using a naked DNA plasmid, reported by Letwin et al in 20/10/00 Science; as of early 2001, , the researchers write in the May 30 SCIENCE. The hormone target is thymosin Thymosin A polypeptide hormone synthesized and secreted by the endodermally derived reticular cells of the thymus gland. Thymosin exerts its actions in several loci: (1) in the thymus gland, either on precursor stem cells derived from fetal liver or from bone alpha1, which promotes the activity of helper T cells, the prime victims of the AIDS virus. The researchers suspected a thymosin-AIDS connection because children with a genetic inability to produce thymosin develop an AIDS-like disease. In a computer match-up of the viral and hormone proteins, they found that about half the components along a short stretch of thymosin are identical to an inner-core AIDS protein. They injected thymosin alpha1 into rabbits and added the resultant antibodies to a human cell line infected with the AIDS virus. "We found we could protect cells [in culture] by adding the antibody,' says Prem S. Sarin sarin (zärēn`), volatile liquid used as a nerve gas. It boils at 147°C; but evaporates quickly at room temperature; its vapor is colorless and odorless. of the National Cancer Institute. The researchers are now searching for a vaccine that will stimulate humans to produce their own antibodies against the AIDS core protein. AIDS vaccine work has focused predominantly on the proteins that surround the viral core, on the presumption that the "envelope' proteins are more exposed to the immune system. But these outer proteins vary from strain to strain of the AIDS virus, complicating the search for a single vaccine. In contrast, the core protein--which George Washington's Allan L. Goldstein calls "the Achilles' heel of the virus'-- apparently remains stable. "We feel we have solved one of the major obstacles to vaccine development--namely, genetic drift genetic drift: see genetics. genetic drift Change in the pool of genes of a small population that takes place strictly by chance. Genetic drift can result in genetic traits being lost from a population or becoming widespread in a population without ,' says Goldstein. For an immune reaction to occur, the core protein must be exposed to antibodies at some point. This may happen, Goldstein suggests, when the virus injects itself into the cell, or if the antibody enters infected cells, or if the core protein is in the envelope as well. Whether the structural similarity between the virus and the hormone is simply coincidental or has a functional explanation, Sarin says, remains an open question. |
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