Human immunodeficiency virus type 1(HIV-1)V2 L175P mutation increases the binding capability of neutralizing antibodies to HIV-1

Abstract

Objective To study the impact of HIV-1 V2 L175P mutation on the binding capability of anti-V3 neutralizing antibodies to HIV-1.Methods A series of eukaryotic cell expression plasmids were used to concatenate wild type and mutant env gene of HIV-1 and green fluorescent protein(GFP)gene.The recombinant plasmids were transfected into 293T cells to express HIV-1 gp120 protein on the surface of cells.The successfully transfected cells were screened by GFP florescence marker.Immunostaining and dual fluorescence flow cytometry were performed to test the binding affinity of several common V3 region specific neutralizing antibodies to wild type or mutant gp120 proteins.Results The mean fluorescence intensity(MFI)of mutant gp120-expressing 293T cells were significantly higher than that of negative control cells(expressing GFP).Flow cytometry showed that the curve for mutant gp120-expressing 293T cells was obviously different in shape and peak from that for the negative control,while most parts of the curve for the wild type gp120-expressing 293T cells overlapped with those for the negative control.Conclusion The V2 region mutation may increase the sensitivity of HIV-1 to the neutralization by V3 region specific antibodies. Key words: HIV-1; gpl20; V2 domain; V3 domain; Neutralizing antibody