Study Spotlights HIV Starting The Infection Process
When transmitted by heterosexual contact from one person to another, the HIV virus faces a genetic bottleneck, as only one type of HIV virus from the many genetic scrambled viruses will start the new infection.
Researchers from the New Emory Vaccine Center have demonstrated that a patient’s new HIV infection differs fundamentally from the HIV main strains that are found in his partner genital tract population. This result spotlights the process of HIV transmission, and the bottleneck effect that is not happening by chance, or due to the partner’s genital tract HIV strains dominant population.
Researchers published their findings in Proceedings of National Academy of Sciences, Early Edition, online this week.
If the new infection strain was determined by chance it would be one strain commonly found in the donor’s genital tract, but this is not the case according to Eric Hunter, PhD senior author, and pathology professor at the Emory university School Of Medicine. The results actually suggest that the transmission method selects certain strains. The HIV virus that will start a new infection is a single variant, but differs totally for each transmission event.
The first author of the paper is Debrah Boeras, senior scientist, PhD.
Patient samples were a result of collaboration with the Emory’s HIV research programs from Rwanda and Zambia, through which the research team received vaginal swabs, blood, and semen from 8 consenting couples from Rwanda and Zambia, exactly when the couples were diagnosed positive to HIV. From the total of eight couples , in six cases, female to male transmission was reported.
Boreas and his team analyzed the DNA sequence that codes the env gene (encodes glycoproteins forming the virus envelope – external coat) and discovered that a single HIV genetic variant from the donor’s genital tract population lead to a new infection. These results could be a starting point for further study regarding the exact features of HIV variants that start a new infection.
The huge challenge will probably be detecting those particular infectious features, identifying the strains and targeting them, in order to protect more people from getting infected.
Other studies concluded that the “founder” HIV viruses , have envelope glycoproteins that are more dense, and have less spaces that can be modified with sugar, feature that may change the way in which these viruses interact with the genital mucosa of the healthy partner.
This aspect is currently in the Hunter laboratory, and the results could help create a new but still elusive vaccine.