Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, March 9, 1995 TAG: 9503090092
SECTION: NATIONAL/INTERNATIONAL PAGE: A-5 EDITION: METRO
SOURCE: Associated Press
DATELINE: NEW YORK LENGTH: Medium
Scientists examined genes from 114 strains of HIV-1 and found that at least 10 strains appeared to be hybrids, blending genetic material from different subtypes of the virus.
HIV-1 is divided into eight or nine subtypes, plus another much different group found in West Africa. Virtually all infections in the United States come from a single subtype. The hybrids in the study were isolated in Africa and South America.
The study raises the question of whether a vaccine that works against parental strains will also protect against their hybrid offspring.
The work is reported in today's issue of the journal Nature by Paul Sharp of the University of Nottingham in England, Dr. Beatrice Hahn of the University of Alabama-Birmingham, and others.
While scientists had known that hybrids of HIV formed within the body's cells occasionally, the study suggests ``it may be happening at a much bigger frequency than we thought,'' said Dr. Dani Bolognesi, director of the AIDS Center at the Duke University Medical School.
The study does not explain how a person gets infected with two strains of HIV, or why the immune system's response to the first infection would not protect against the second infection. Maybe there is not enough time between infections to build immune defenses, the researchers said.
Bolognesi said it is not clear how long it takes for the body's defenses to reach full strength after an HIV-1 infection, but that it probably takes several months.
by CNB