T-cell Epitopes Identified by BALB/c Mice Immunized with Vaccinia Expressing HIV-1 Gag lie within immunodominant Regions Recognized by HIV-infected Indian Patients.

BACKGROUND

Human immunodeficiency virus (HIV) antigens from transmitted strains of HIV would prove crucial in vaccine designing for prevention of HIV infection. Immune response generated by Vaccinia construct expressing the HIV-1 gag gene from transmitted Indian HIV-1 subtype C strain (Vgag) in BALB/c mice is reported in the present study along with the identification of epitopes responsible for induction of the immune response.

AIMS

The aim of this study was to determine immune response generated by the constructs in a mouse model and to understand the epitope specificities of the response.

SETTINGS AND DESIGN

This was an observational study carried out in BALB/c mice.

MATERIALS AND METHODS

The immunogenecity of Vgag construct was evaluated in BALB/c mice after multiple immunizations. T-cell response was monitored by the interferon-γ ELISPOT assay using HIV-1 C Gag overlapping peptides and anti-P24 antibodies were estimated by ELISA.

STATISTICAL ANALYSIS USED

Graphpad prism software was used for statistical analysis and for plotting graphs.

RESULTS

IFN-γ-secreting T cells and antibodies were detected against HIV Gag in mice after immunization. Although after repeated immunizations, antibody-mediated immune response increased or remained sustained, the magnitude of IFN-γ-secreting T cell was found to be decreased over time. The Gag peptides recognized by mice were mainly confined to the P24 region and had a considerable overlap with earlier reported immunodominant regions recognized by HIV-infected Indian patients.

CONCLUSION

Vaccinia construct with a gag gene from transmitted HIV-1 virus was found to be immunogenic. The Gag regions identified by mice could have important implications in terms of future HIV vaccine designing.