Phenotypic studies on recombinant human immunodeficiency virus type 1 (HIV-1) containing CRF01_AE env gene derived from HIV-1-infected patient, residing in central Thailand

Two N-Linked Glycosylation Sites in the V2 and C2 Regions of Human Immunodeficiency Virus Type 1 CRF01_AE Envelope Glycoprotein gp120 Regulate Viral Neutralization Susceptibility to the Human Monoclonal Antibody Specific for the CD4 Binding Domain

“…Two CRF01_AE Env clones, 65CC1 and 65CC4, showed distinct neutralization susceptibility to b12 (47), although these CRF01_AE Env clones had a close phylogenetic relationship (46). In addition, our previous results suggested that the determinants of b12 resistance of 65CC4 were located within the N-terminal regions (C1, V1, V2, C2, V3, and a 36-amino-acid sequence of C3 before the XbaI recognition site) of Env gp120 (47). First, we confirmed our previous results by performing neutralization tests using 4 CRF01_AE Env recombinant viruses.…”

“…Recent studies on CRF01_AE (40,47) and subtype C Env (39) showed that viral susceptibility to neutralizing antibodies was inversely correlated with the length of V1 and V2 regions of Env gp120. In addition, several CRF01_AE Env clones that contain a long V2 region, similar to 65CC1 (46), were resistant to b12-mediated neutralization (47). Thus, we considered that short V1 and V2 regions of 65CC4 might not account for the lower b12 susceptibility of 65CC4 compared to 65CC1.…”

“…In particular, this subtype is responsible for more than 95% of infection cases in Thailand, Cambodia, and Viet Nam (13). Although b12 is able to broadly neutralize HIV-1 subtype B, C, and D clinical isolates, it poorly neutralizes many CRF01_AE strains (3,47,49); however, the mechanisms why CRF01_AE viruses show low susceptibility to b12-mediated neutralization are still not understood.…”

“…Recently, we established 35 infectious CRF01_AE Env recombinant viruses, and studied their neutralization susceptibility to neutralizing human monoclonal antibodies, patient serum and HIV-1 entry inhibitors (46,47). Among them, a recombinant virus containing CRF01_AE Env, 65CC1 was susceptible to b12, while 34 remaining CRF01_AE Env recombinant viruses, including the virus containing CRF01_AE Env, 65CC4, were resistant to b12 (47).…”

“…Among them, a recombinant virus containing CRF01_AE Env, 65CC1 was susceptible to b12, while 34 remaining CRF01_AE Env recombinant viruses, including the virus containing CRF01_AE Env, 65CC4, were resistant to b12 (47). In this report, we examined the molecular mechanisms underlying the low b12 susceptibility of CRF01_AE Env, using these CRF01_AE Env recombinant viruses.…”