[Molecular analysis of the principal neutralization epitope (V3 loop) of human immunodeficiency virus type 1 in Argentina].

The main goal of the present paper was to analyze the molecular diversity of the principal neutralizing domain (V3 loop) of the HIV 1 gp120 in samples from patients of Argentina. The study was carried out on a total of 30 HIV 1 positive blood samples, obtained during 1991-1992, belonging to 15 intravenous drug users (group A), 5 homosexual men (group B), 8 children born to HIV 1 positive mothers (group C) and 2 AIDS patients (group D). By using extracted DNA from peripheral blood lymphocytes and from infected cells of the viral isolates in the case of the 2 AIDS patients, the V3 loop region was amplified by means of polymerase chain reaction. Direct sequencing by Sanger methodology was then performed on DNA fragments and nucleotide sequences obtained were translated into the correspondent amino acids. Consensus sequences for each group and a general consensus sequence were established (Table 1). Its alignment with V3 loop amino acid sequences of the major HIV 1 strains isolated worldwide is showed in table 2. Homology analysis between each sequence of the study population and sequence of different HIV 1 isolates showed that most of these samples share high homology with SF2 and BH10 strains. In contrast a low homology was found with JH3 and MN isolated (table 3). The presence of highly conserved amino acid residues as substitutions and insertions was determined in the Argentinian V3 loop sequences giving them a local pattern. The present paper is of great importance for our country, considering that the V3 loop is the main neutralizing domain becoming a major target in the development of HIV 1 vaccine. To our knowledge, this is the first report on the sequencing of the principal neutralizing domain of the Human Immunodeficiency Virus type 1 in Latin America.