Two viruses identified (so far) which cause acquired immune deficiency syndrome (AIDS). HIV-1 and HIV-2 show a preferential tropism (affinity) toward the helper T cells, although other immune system (and nervous system) cells are also infected. The GP120 envelope (surface) protein of HIV-1 and HIV-2 directly interacts (binds) with the CD4 proteins (receptors) on the surface of helper T cells, enabling the viruses to bind (attach to) and infect the helper T cells. In order to successfully enter and infect cells, the HIV must also bind with CKR-5 proteins (receptors) located on the surface of cells of most humans. In 1996, Nathaniel Landau and Richard Koup discovered that approximately one percent of humans carry a gene for a version of CKR-5 receptor that resists entry to cells by HIV. As of 1996, a total of nine separate strains (serotypes) of Human Immunodeficiency Virus were known; identified by the letters A, B, C, D, E, F, G, H, I.<\/p>\n
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Two viruses identified (so far) which cause acquired immune deficiency syndrome (AIDS). HIV-1 and HIV-2 show a preferential tropism (affinity) toward the helper T cells, although other immune system (and nervous system) cells are also infected. The GP120 envelope (surface) protein of HIV-1 and HIV-2 directly interacts (binds) with the CD4 proteins (receptors) on the […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-38211","post","type-post","status-publish","format-standard","hentry","category-h"],"yoast_head":"\n