Hyperglycosylated N-Linked Site 339 of gp120 Appears to Be Unique and May Contribute to CRF01_AE Transmission Among Men Who Have Sex with Men in China and Thailand

Human immunodeficiency virus (HIV)-1 CRF01_AE is one of the most important genotypes in China, especially in the population of men who have sex with men (MSM). It has become the most prevalent strain among them. Describing the variant characterization of CRF01_AE will help to reveal the reason behind its predominance in MSM. In this study, the complete DNA sequences (CDSs) for gp120 from the envelope protein (env) gene of CRF01_AE in China and Thailand were retrieved from the Los Alamos HIV database. The CDSs for gp120 were divided into three subgroups according to the risk factors for HIV-1 transmission in a variety of populations, such as intravenous drug users (IDU), heterosexual contacts (HC), and MSM. The N-linked CDS glycosylation sites for gp120 in CRF01_AE were analyzed. The results showed a unique hyperglycosylation site N-339 (refer to Hxb2) in the gp120 of CRF01_AE in MSM compared with the IDU and HC groups from China. The result was the same in the MSM group from Thailand, which suggests that the hyperglycosylation site N-339 may explain the widespread CRF01_AE genotype in MSM.