Immune Responses against a New HIV-1 p24-gp41/pCAGGS-IL-12 DNA Vaccine in Balb/c Mice.

Fatemeh Roodbari (1, 2) , Farzaneh Sabahi (1) , Mohamad Nabi Sarbolouki (3) , Farzaneh Barkhordari (4) , Ahmad Adeli (4) , Amel Jamedar (5, 1) , Fereidoun Mahboudi (4)

1 Department of Virology, Faculty of Medical Sciences
2 Department of Cellular and Molecular Biology, Faculty of Basic Sciences
3 Institute of Biochemistry and Biophysics
4 Biotechnology Research Center
5 Department of Microbiology and Virology, Faculty of Medicine

Background: Development of an effective vaccine is highly needed in order to restrict the AIDS pandemic. DNA vaccines initiate both arms of immunity without the potential of causing disease. HIV-1 p24 and gp41 (gag and env) proteins play important roles in viral pathogenesis and are effective candidates for immune induction and vaccine design. Objective: In this study, new DNA vaccine candidates constructed from HIV-1 fused p24-gp41 or gp41 alone were evaluated in Balb/c mice for induction of cellular and humoral immune responses. Methods: Recombinant plasmids, pcDNA3.1/Hygro expression vector containing immunogenic sequences of fused p24-gp41 or gp41alone were produced. Dendrosome used as a system for carrying vectors in laboratory animals, and an IL-12 containing vector (pCAGGS-IL-12) was co-immunized with the p24-gp41 vector as a genetic adjuvant. Induction of effective immune responses against the designed vectors as DNA vaccine candidates in Balb/c mice was evaluated. Levels of total antibodies, IgG isotypes (IgG2a and IgG1); IFN-γ and IL-4 were measured by ELISA. MTT assay was used to evaluate lymphoproliferation. Results: The results confirmed that the immunogenic epitopes of both p24 and gp41 genes are highly effective inducers of immune responses, and administration of fused p24-gp41 alone or along with IL-12 resulted in further enhancement of immune responses. Group 4 that received fused fragments (p24-gp41) along with an IL-12 expressing vector demonstrated a significantly higher Stimulation Index (SI) and IFN-γ production (p<0.0001) with a significant increase in IgG2a/IgG1 ratio, indicating the stimulation of CMI towards Th1. Although gp41 containing vector (group 6) also showed significant increases in both proliferation and IFN-γ production, the responses were persistently lower than that of p24-gp41 containing vectors. Total antibody production was highest in group 6 as expected. Conclusion: Dendrosome proved to be an efficient carrier of recombinant plasmids constructed in this study. Further studies are necessary to evaluate these constructs as HIV vaccine candidates.

Keywords: Dendrosome; DNA Vaccine; gp41; HIV-1; IL-12; p24

Domains: Life Sciences [q-bio]; Immunology

Fatemeh Roodbari, Farzaneh Sabahi, Mohamad Nabi Sarbolouki, Farzaneh Barkhordari, Ahmad Adeli, et al.. Immune Responses against a New HIV-1 p24-gp41/pCAGGS-IL-12 DNA Vaccine in Balb/c Mice.. Iranian Journal of Immunology, 2012, 9 (2), pp.86-97. ⟨pasteur-00826030⟩