Genetic Variations in HIV
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AIDS is caused by the HIV virus, and its treatment is difficult because the virus comes in many strains, and mutations occur frequently, producing even more strains, often ones which are resistant to current medications. Multiple human immunodeficiency virus type 1 (HIV-1) genetic subtypes, intersubtype recombinants, and group O have been found in west central Africa (McCutchan et al, 1999, p. 226). In Nigeria, three major subtypes, G, A, and O, and some recombinants within these have been found. A study which looked at human immunodeficiency virus type 1 isolates from 207 patients with CD4+ cell counts less than 500/mm3 were examined for biological phenotype in MT-2 cells (Nicastri, et al, 1998, p. 90). Three subtypes of syncytium-inducing strains and two subtypes of nonsyncytium-inducing isolates were identified. HIV infection in Brazil is one of the highest in the world, and a study characterized 43 seropositive blood units collected from volunteer blood donors living in Rio de Janeiro and looked at genetic heterogeneity (Tanuri, et al, 1999). The majority of samples contained type B or F, but their were also potential mosaic viruses of subtypes B and F or B and D. This is the first study to show genetic variations in HIV-1 in the Brazilian blood-donor population. Swiss and U. S. scientists have found that different strains of HIV can be present in one person (Birchard, 1998, p. 1363). Teams from a hospital in Carolina and one in Switzerland studie
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of DNA entry into cells. Each adjuvant has unique immunomodulatory effects on cell-mediated and humoral immune responses induced by DNA vaccination to human immunodeficiency virus type 1.
In a similar study, plasmids encoding costimulatory molecule B7 and interleukin-12 genes were codelivered with DNA vaccine for HIV-1. Thus multicomponent DNA immunization can be used to elicit specific humoral and cell-mediated immune responses against different antigenic targets of HIV-1.
One problem with developing a vaccine against AIDS is that early vaccines were made against HIV envelope glycoproteins, but these glycoproteins change shape as the virus fuses with the cells it infects, and the antibodies are unable to block it (Carey, 1999, p. 105). Then it is necessary to isolate the virus in the act of fusing to cell receptors to isolate it in the new shape for the purpose of antibody production. This has now been done on a small scale, but still presents a difficult problem to overcome in making a vaccine.
Another problem is the development of resistant strains which resist neutralization (Henderson, 1998, p. NA). There are to date only three monoclonal antibodies that strongly neutralize most primary strains of HIV-1: 2G12, 2F
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Some common words found in the essay are:
Fukushima Okuda, Sustiva Pediatric, Persons Aged, Coutton Cherman, Africa McCutchan, HIV-1 RNA, Minkoff Landesman, Thirty HIV/AIDS, Human Retrovirology, Medical Association, type 1, immunodeficiency virus type, virus type 1, virus type, human immunodeficiency virus, immunodeficiency virus, human immunodeficiency, henderson 1998, weekly plus, protease inhibitors, aids weekly, et al, aids weekly plus, retrovirology 20, human retrovirology 20,
Approximate Word count = 2803
Approximate Pages = 11 (250 words per page)
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