Mechanisms of Human Immunodeficiency Virus (hiv) Escape from the Immune Response

The acquired immunodeficiency syndrome (AIDS) was identified as a new disease in 1981 (1,2) and, its aetiological agent, the human immunodeficiency virus (HIV), was discovered in 1983 (3). Two types of HIV, i.e. HIV-1 and HIV-2, have been identified (4). Both HIV-1 and HIV-2 have similar structures, tropisms and disease outcome, although they have limited shared nucleotide sequence homology (42%) and limited antigenic cross reactivity (5). HIV is predominantly transmitted via sexual activity, the exchange of blood or body fluids contamined by the virus, and from mother to child. CD4+ T lymphocytes, monocytes and macrophages are the major targets of HIV.