Hiv And Aids A Member Of The Lentivirus Family - 1330 Words

HIV-1 and AIDS Overall HIV is a member of the lentivirus family. There are two types of HIV: HIV-1 and HIV-2. Although both types infect cells in similar ways and appear to cause clinically indistinguishable AIDS, studies showed that HIV-1 is the predominant virus type. Infections of HIV-2 are: 1) rarely found outside of West Africa (de Silva et al., 2008), and 2) seldom progressed to AIDS or lead to HAND (Rowland-Jones and Whittle, 2007). On the other hand, more than 34 million individuals were infected by HIV-1 by the end of 2009 (UNAIDS, 2010). Currently, four strains of HIV-1 have been identified: the major group M, the outlier group O and two new groups N and P. At least 9 genetically distinct subtypes, designated as clades A, B, C,†¦show more content†¦This binding induces a conformational change in gp120, which exposes its binding site to its cellular co-receptors. CCR5 and CXCR4, two receptors first identified as CC- and CXC- chemokine receptors, respectively, are the most reported co-rece ptors for HIV infection. Other chemokine receptors, including CCR2, CCR3, and CX3CR1 have also been reported to be utilized by HIV as co-receptors (He et al., 1997; Garin et al., 2003; Puissant et al., 2003). The Interaction between gp120 and these co-receptors triggers further conformational change and the insertion of HIV-1 gp41 into the host cell membrane, which initiates the fusion of the membranes and eventually leads to entry of the virus genome and proteins. Once the host cell is infected, the viral reverse transcriptase makes viral DNA using its RNA genome template. The newly synthesized viral DNA binds to the viral protein integrase and some host proteins to form the pre-integration complex, which then translocate to the nucleus, integrate to the host genome, and form the provirus. Infected cells can either be latent, or actively transcribe and produce virus and viral proteins such as Tat, gp120, Nef and Vpr. The first case of HIV infection in the United States can be dated back to the 1970s, and AIDS was reported in New York and California in the 1980s. By 1983, approximately 3000 AIDS patients had been reported and 1000 patients had died (Berkson, 1990). Over 33 million