20 May 2008

Not all HIV strains are equally contagious

In the works on the study of HIV/AIDS has been identified as the so-called "bottleneck effect", manifested in the fact that only a few of the numerous strains of the virus contained in the blood of an HIV-infected person ensure the further spread of infection. Scientists at the University of Alabama (Birmingham), working under the guidance of Professor George Shaw (George M. Shaw), for the first time used genetic analysis and mathematical modeling to accurately identify "contagious" HIV-1 strains.

The authors decoded the sequences of a large number of copies of the Env gene belonging to viruses isolated from the blood of 102 recently infected patients. The Env gene encodes a protein that forms the outer shell of the virus and is responsible for its infectivity – the ease with which the causative agent of the disease is transmitted from an infected organism to an uninfected one.

Using a complex mathematical model of HIV replication and genetic modification, the researchers identified the strains responsible for transmission of infection. In 80% of cases of fresh infections, infection occurred when one strain of the virus, unique to each patient, entered the body. In the remaining 20% of cases, from 2 to 5 variants of HIV were responsible for transmission of infection.

Previously, experts used inaccurate techniques that did not allow for unambiguous identification of the virus that caused the infection. The approach developed by the authors makes it possible to identify not only the virus that infected the patient, but also the strains formed as a result of its modification. Scientists believe that the results of the study will facilitate the work on studying how combinations of different genes and proteins of the virus ensure its infectivity and ability to develop in the conditions of immunity forming in the body. The ultimate goal of working in this direction is to create an effective and safe HIV vaccine.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily


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