Caracterização molecular dos genótipos C, F1 e BC do Vírus da Imunodeficiência Humana tipo 1 (HIV-1) circulantes na região Nordeste do Brasil - análise da dispersão e história evolutiva.

Abstract

INTRODUCTION: The Human Immunodeficiency Virus (HIV) is the etiological agent of the Acquired Immunodeficiency Syndrome (AIDS), a without a vaccine or cure. HIV-1 presents an extensive genetic variability and in Brazil, subtypes B, C and subsubtype F1 are the prevalent genotypes and intersubtype recombinants such as BC and BF1 are also detected. Non-B subtypes have increased in frequency in Brazil. OBJECTIVE: To identify non-B viral isolates of HIV-1 (subtype C, subsubtype F1 and BC recombinant) in Bahia and to analyze the dispersion route and genotypic and molecular characteristics. MATERIAL AND METHODS: Whole blood samples was collected from patients with HIV-1 followed up at the Professor Edgard Santos University Hospital. The genomic DNA was extracted and sequenced by the Sanger method. The genomes were assembled using the GENEIOUS software. Reference alignments were generated for molecular and phylogenetic analyzes from sequences available in the Los Alamos database and were analyzed through Bioinformatic softwares. RESULTS: Through the obtaining whole blood samples 5 subtype C sequences, 19 BF1 and F1 sequences and 1 BC recombinant sequences were obtained. The phylodynamic analyzes estimated that the F1 sub-subtype reached the Brazilian territory around the 70's. The C subtype reached the Northeast region around 1985, from the South, Southeast and Central-west regions, and the C strain found in Bahia descends from the lineage of the South region. The BC sample from our cohort showed a common recombination point to other Brazilian recombinants. The genetic characterization of BC genomes reveals a preferential recombination point with the B fragment conserved in pol, env and nef genes. The molecular characterization of near-full length genome of local and global subtype C suggests that the most of strain has a low replicative capacity. CONCLUSIONS: The F1 Brazilian isolates belongs to a single lineage, which descends from the Central-West of the Africa. The subtype C found in the Northeast region and state of Bahia descends from the South region, circulating in the region since 1985. The new pattern of BC sequence may represent a new CRF in Brazil. The genomic analyzes results of recombinant BC strains reveal that characteristics of subtype B maintained in BC strains may favor adaptative advantages. Concerning the pure C genotype, the amino acid and molecular characteristics pointing to a favor this subtype transmission.