Evaluation of the Diagnostic Efficiency of a Recombinant Antigen Modeling the Immunogenic Epitope V3 of the Envelope Protein gpl20 for Immunoenzyme Detection of Antibodies to HIV-1

摘要

It is known that the third hypervariable domain V3 of the HIV-1 glycoprotein gpl20 plays a major role in the interaction with neutralizing antibodies and is one of the significant serologic markers in_the diagnosis of HIV infection. Neutralization of the antibodies is ensured by the conserved tripeptide GPG, a structural component of the V3 loop. The influence of variations of the amino acid composition of the V3 region of the gpl20 glycoprotein on the antigenic properties was studied using five synthetic peptides. The primary structure of the peptide V3-C, the most immunoreactive according to the results of enzyme immunoassay (ELISA), was selected as the basis for creating the recombinant analog. The sequence of the V3-C loop of gpl2O was assembled by the PCR method and cloned in the vector pET41b. The plasmid containing the insert was expressed in E. coli cells; the recombinant protein obtained was purified on an affinity carrier. The activity of the antigen was compared with the activity of an analogous synthetic peptide by the ELISA method. The results permitted the selection of the most immunoreactive variant of the amino acid sequence of the V3 region, which exhibited more pronounced antigenic properties of the recombinant protein in comparison with an analogous peptide. The evaluation of this antigen shows that it is a good candidate for use in the diagnosis of HIV infection.