[Structural and functional relationships demonstrated by the study of V3 loop heterogeneity]. / Relations entre la structure et la fonction révélées par l'étude de l'hétérogénéité de la boucle V3.

ABSTRACT

Data obtained from genomic sequence analysis of the gp 120 V3 loop show that some of the phenotype features depend on the modifications produced in the amino acid sequence of this region. Phenotypical characterization of HIV isolates is based on their sensitivity to neutralizing antibodies, the appearance of virus variants showing unusual tropism, higher cytopathogenicity in vitro and modified virulence in vivo, etc. Sequencing data published since now concern strains from the Euro-American area only, the other geographical areas being neglected. So, these informations support some relations between structure and function, but don't allow a prediction about the evolutive capacity of HIV strains, the distinction between conserved and variable regions nor the understanding of medical signification of some specific genomic changes. Three aspects important for clinical evolution of the disease are discussed in detail genomic changes in V3 encoding sequence associated with virulence, changes associated with neurotropism for macrophages, changes conditioning sensitivity to neutralizing antibodies.