RESUMO
The SIV-infected macaque provides an excellent model to study factors involved in maternal-fetal transmission of HIV. In our prenatal transmission studies, female macaques were inoculated intravenously during midgestation with either SIV/DeltaB670 or a combination of SIV/ DeltaB670 and the macrophage-tropic molecular clone SIV/17E-Fr. The females harbored a genetically diverse virus population at parturition, whereas a single genotype from the maternal quasispecies was identified in the infants. One of two variants was transplacentally transmitted to the infants, SIV/17E-Fr or B670-Cl 12, a genotype contained within the SIV/ DeltaB670 inoculum. Both of these variants have been identified in the central nervous system of macaques that have developed encephalitis and they replicate in vitro on primary rhesus macrophages. These results suggest a critical role for macrophages in fetal infection in utero. In our perinatal transmission studies we have evaluated the viral genotypes found in two newborn macaques infected orally with SIV/DeltaB670 and in one infant infected via amniotic inoculation in late gestation. More than one viral genotype was identified in each infant, moreover, each infant harbored different genotypes. These results suggest different mechanisms are responsible for viral infection via these routes.
Assuntos
Complicações Infecciosas na Gravidez , Síndrome de Imunodeficiência Adquirida dos Símios/transmissão , Vírus da Imunodeficiência Símia/genética , Proteínas do Envelope Viral/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Primers do DNA , Feminino , Genes env , Variação Genética , Genótipo , Transmissão Vertical de Doenças Infecciosas , Macaca mulatta , Modelos Biológicos , Dados de Sequência Molecular , Placenta , Reação em Cadeia da Polimerase , Gravidez , Homologia de Sequência de Aminoácidos , Síndrome de Imunodeficiência Adquirida dos Símios/embriologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/isolamento & purificação , Proteínas do Envelope Viral/químicaRESUMO
A hypothetical model of the surface (SU) glycoproteins of human immunodeficiency virus (HIV) and other retroviruses is proposed. The model is based on repetition of a limited number of sequence motifs conserved within the virus family; similarities in biological, immunological, or genetic properties; as well as the tendency for regions of dissimilar sequence to share protein structures predicted by computer algorithms. It is proposed that the protein consists of three structural and functional domains interspersed by relatively conserved interdomain regions. For each retrovirus, these amino-terminal, central, and carboxy-terminal domains may play different roles in binding, postbinding events, and the immune response to viral infection.
