Background: Recombinant cytotoxic T lymphocyte (CTL) epitope DNA vaccines offer an attractive approach for the induction of robust cellular and humoral immune responses directed against human pathogen target antigens.
Aim: To construct a pVAX-gD-CTL vector expressing the glycoprotein (g)D and gB CTL epitopes from herpes simplex virus type 2 (HSV2) and evaluate it in mice for immunogenicity and protective efficacy against intraperitoneal challenge with the HSV2 strain Sav.
Methods: The gD gene transcript and gB CTL epitope were inserted into the pVAX vector to obtain the recombinant plasmid pVAX-gD-CTL. An in vitro study was then conducted to detect the expression of gD by immunocytochemistry and western blotting. BALB/c mice were immunized with this DNA vaccine, then the CTL activity and expression of anti-HSV2 gD IgG, interferon-gamma and interleukin-4 by lactate dehydrogenase release assay and ELISA, respectively. The protection given to the mice was assayed by a fatal dose of virus.
Results: The pVAX-gD-CTL vector was successfully constructed and could express gD in COS-7 cells. Immunogenicity of gD, anti-HSV2 gD neutralizing serum IgG antibody and robust Th1-polarized immune responses were found. Furthermore, mice were prophylactically protected from challenge with a high dose of HSV2.
Conclusions: In summary, pVAX-gD-CTL vector was successfully used to elicit potent Th1-like cellular and humoral immune responses that were protective against HSV2 disease in mice.