Two Antigenically Distinct Subtypes of Human Immunodeficiency Virus Type 1: Viral Genotype Predicts Neutralization Serotype

Human Immunodeficiency Virus Type 1 Neutralization Measured by Flow Cytometric Quantitation of Single-Round Infection of Primary Human T Cells

“…These assays were shown to be quantitative and reproducible but were limited to syncytium-forming viruses that used the CXCR4 coreceptor present on T-cell lines (6). This led to the use of primary mononuclear cells as target cells, because all HIV-1 isolates could be propagated in activated peripheral blood mononuclear cells (PBMC) (1,41,46,56,60). In addition, studies have shown that the in vivo protection mediated by passive transfer of anti-HIV-1 neutralizing antibodies to severe combined immunodeficiency mice reconstituted with human PBMC (24) or to rhesus macaques (5,38,43,53,64) could be predicted by the potency of neutralization measured by in vitro assays using PBMC target cells.…”

“…Most PBMC neutralization assays monitor virus growth by assaying for extracellular expression of viral proteins such as p24 antigen (p24-Ag) or reverse transcriptase (1,3,41,46,75). These assays require several rounds of virus replication before expressed proteins can be quantified and thus only indirectly measure the actual number of target cells infected.…”

“…These assays require several rounds of virus replication before expressed proteins can be quantified and thus only indirectly measure the actual number of target cells infected. We have commonly used enzyme-linked immunosorbent assay (ELISA) measurement of p24-Ag expressed into culture supernatants as an endpoint in PBMC neutralization assays (40)(41)(42). Although this assay does not measure single-round virus replication, we closely monitor virus growth kinetics to measure secreted p24-Ag expression during the early viral growth phase (36).…”

Human immunodeficiency virus type 1 neutralization by plasma from B or F genotype infected individuals

“…Attempts to "immunotype", "serotype" or "neutrotype" HIV-1 have shown that, although "reactivity clusters" can be identified (Bradac & Ho 1992, McKnight et al 1992, Mascola et al 1994, Cheingsong-Popov et al 1994, Weber et al 1996, Kostrikis et al 1996, Zolla-Pazner et al 1999, Zhang et al 2002, Zolla-Pazner 2004, these have little correlation to the clades identified by genotyping HIV-1. In Southeastern Brazil, although infection by the so-called Brazilian variant of the classical B clade of HIV-1, Bbr, can mostly be distinguished by a more specific reactivity pattern towards homologous synthetic peptides, no distinction of plasma of individuals infected with the prevalent B or the F clades of HIV-1 could be observed using synthetic envelope peptides (Bongertz et al 2003).…”

Epidemiologia: contextos e pluralidade

“…Estudos iniciais sugeriam uma concordância entre subtipo genético e resultados obtidos por testes de neutralização (Mascola et al, 1994). Estes resultados não foram confirmados por outros grupos (Nkengasong et al, 1994b).…”