Sexual Health news - Sexually Transmitted Diseases

Protein sequence of immune killer cells controls HIV naturally

Some recent HIV research has been focusing on targeting the specific cells, known as CD8 T cells, in the body that help kill off HIV-infected cells. One in every 300 people has the ability to control HIV naturally, and it has been established that it is not the quantity of CD8 T cells that gives them this extra defense, but rather the quality.

CD8 T cells need to possess T-cell receptors, which are essential to killing the virus. These proteins have a specific sequence that is different in individuals who can control HIV when compared to people without the ability, according to a study published in the journal Natural Immunology.

The study observed genetic and other differences that may underlie the ability to control HIV by looking at individuals with the HLA B27 gene who had increased viral loads and comparing them to those who did not.

Previous studies have investigated a particular version of HLA-B gene - which activates the production of immune system proteins that flag infected cells for destruction by CD8 T cells - to see how it associated with natural HIV maintenance. Only a 20 percent difference in protein sequencing was revealed between participants who could control HIV and those who couldn't.

The recent study concluded that there was no significant difference in the number of CD8 T cells between controllers and non controllers, whereas there was great variability in protein sequences that allowed them to efficiently kill the virus and respond to mutations.

"A big remaining question is why these particularly effective killer cells are generated in some people but not in others. At this point we don't know why, but now we know what we are looking for," says Bruce Walker, M.D., a professor of Medicine at Harvard Medical School. "We also need to investigate whether a vaccine can induce production of these effective killer cells."
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