Genotypic and Phenotypic Characterization of HIV-1 CRF01_AE Env Molecular Clones from Infections in China

Background: Although a great number of HIV-1 pseudoviruses have been generated for neutralization assays, circulating recombinant forms, such as CRF01_AE, are not included. Given the increasing prevalence of CRF01_AE, the establishment of a pool of CRF01_AE env isolates for the evaluation of potential HIV vaccines is needed.

Materials And Methods: Full-length env genes were cloned from HIV-1 CRF01_AE-infected plasma samples collected in China and used to establish Env-pseudotyped viruses. The neutralization phenotypes of the pseudoviruses were characterized by testing against broadly neutralizing monoclonal antibodies, coreceptor antagonists, and 42 plasma samples that include 3 main prevalent HIV-1 subtypes in China.

Results: Thirty-four genetically distinct CRF01_AE env genes were cloned and used to generate pseudotyped viruses. Of the 34 pseudoviruses, 32 used CCR5 as a coreceptor and 2 used CXCR4. The majority of pseudoviruses were resistant to the neutralizing antibodies IgG1b12 and 2G12 and susceptible to 2F5 and 4E10. There was significant variation of the neutralization susceptibility of pseudoviruses against 42 HIV-1-positive plasma samples. Based on their overall neutralization susceptibilities, the 34 CRF01_AE pseudoviruses were classified into 3 tiers: high, medium, and low.

Conclusion: The CRF01_AE pseudovirus isolates should be included in the panel of pseudoviruses used to assess vaccine-elicited neutralizing antibodies.