Function and polymorphisms of anti-HIV host factors: Evidence from exposed uninfected individuals

Several host factors, that is, factors that at least in part could protect individuals from becoming HIV infected, have been described. Individuals who do not become infected despite repeated exposure are exposed, uninfected individuals. In this review, we briefly describe some host factors that might contribute to protection from HIV infection in these exposed uninfected individuals. Alteration in chemokine levels and chemokine receptors were the first of these factors described that are associated with some exposed uninfected individuals. More recently, mutations in cytokine factors, notably interferon regulatory factor 1, have been described in a Kenyan commercial sex workers cohort who have remained uninfected despite multiple exposures to HIV-infected clients. Receptors on dendritic cells offer the opportunity to protect individuals where transmission of the virus would occur by the mucosal route. Similarly, several host restriction factors have anti-HIV activity; these include APOBEC3G, TRIM5α and other host factors.