Complications Of HIV: What Is HIV?
Human immunodeficiency virus (HIV) is a Lentivirus from the family Retroviridiae ,which infects CD4+ T cells, dendritic cells and macrophages. This results in a loss in immune function and eventually acquired immune deficiency syndrome (AIDS) when CD4+ cell count is very low. There were approximately 1.5 million deaths in 2013 as a result of HIV-related causes , many of these deaths occur due to the immune system being too weak to defend itself against opportunistic infections .
HIV has 2 different forms, HIV-1 and HIV-2. HIV-2 is less virulent and also less infective, limiting it to West Africa because of its lower transmission rate . HIV-1 is further divided into M,N, O and P groups, with M being the pandemic …show more content…
As well as sites for antiretrovirals to act (shown in green …show more content…
This then allows gp41, a transmembrane protein that contains a fusion peptide, to allow the viral envelope to fuse with the cell membrane and release the capsid into the cell.
Reverse Transcription - After entry into the cell, the virus is uncoated releasing viral RNA and reverse transcriptase into the cell cytoplasm. Reverse transcriptase acts on this RNA and generates double stranded DNA, this viral DNA is then packaged with other viral proteins (reverse transcriptase, integrase, protease and viral protein r) to form a pre-integration complex (PIC).
Integration - The PIC then travels to the nucleus where it needs to wait for the breakdown of the nuclear envelope before crossing. Integrase then cleaves the GT dinucleotide from the 3 ' end of the viral DNA to expose a hydroxyl group which acts as a nucleophile. Integrase then deforms the phosphodiester bonds in order to make them susceptible to nucleophilic attack allowing the 3 ' viral DNA end to join to the host DNA 5 '