Background: HIV recombinant proteins can be used as immunogen and inducer of immune system. The gag and env proteins are among the most important ones that are located on internal and surface sections, respectively. In this study, we considered the immunogenisity structure of HIV recombinant protein gp41-p24, which has not yet been studied in detail before.

 Materials and Methods: In the present study, the HIV recombinant protein gp41-p24 was prepared by cloning methods and kept as unfolded. Using the dilution procedure, unfolded protein was changed to refolded state. The molecular weight and concentration of protein (refolded and unfolded) was measured by electrophoresis and spectrophotometer methods. The measurement of refolded protein can be estimated by native gel and circular dichroism method (CD) based on secondary structure of the protein. Immunological activity and immunogenic structure of these two proteins, based on protein type and optical density was recorded by ELISA and western blot methods.

Results: Our results showed that molecular weight of each protein was 32 KD and also they were pure. The refolded protein was observed by native gel method. In the above protein compared with the unfolded one, increased content of helix and beta strand structures and decreased random form was shown. Immune reaction with the antibodies in the serum of HIV positive control patients was observed in the standard and refolded proteins. There was no significant difference based on the protein type.

 Conclusion: Our research indicated that the HIV recombinant protein gp41-p24, after refolding, has immunogenic activity and we suggest its application as an immunogen in immunization and stimulation of immune system.