[Finding the traces of the HIV selection].

Abstract

Recent evidences establish that the evolution of the Human Immunodeficiency Virus in the present epidemic has an adaptive component. The main selective pressure on HIV consists of cytotoxic T lymphocytes (CTLs) recognition of viral peptides on infected cells associated to class I HLA molecules. Since each HLA allele recognizes a defined repertoire of peptides, escape mutations will reflect the HLA alleles present in individuals or populations. Initial findings demonstrated the possibility of adaptive evolution in HIV, by showing the role of CTLs in infection control, the emergence of escape mutants, and their ability to be transmitted and accumulate. The subsequent finding of a population-level association between viral sequence polymorphisms and particular alleles in the hosts was considered a mark of CTL selection on HIV. Subsequent studies experimentally verified the immunological mechanisms of this selection and it is present occurrence. The strategies of these studies, based on the evaluation of immunological hypothesis suggested by statistical findings on virus and host polymorphisms, offer novel opportunities of research in topics as the interaction between immune and antiretroviral drug pressures, and the biological relevance of fitness of viral variants.