Induction of HSV-gD2 specific CD4(+) cells in Peyer's patches and mucosal antibody responses in mice following DNA immunization by both parenteral and mucosal administration.

A DNA vaccine encoding glycoprotein D (gD) of herpes simplex virus type 2 (pHSV-gD2) was injected via parenteral and mucosal routes to determine the optimal route of delivery for immune stimulation. Generation of distal mucosal immunity following parenteral vaccination was also evaluated. While all routes of DNA vaccine administration resulted in systemic cellular and humoral responses, the intra-muscular (i.m.) and intra-dermal (i.d.) routes of delivery produced the highest responses. Furthermore, i.m. and i.d. routes produced mucosal humoral responses that were comparable to those obtained via mucosal routes. Specific pHSV-gD2 PCR signals were detected in the Peyer's patches (PP) within hours following vaccination and antigen specific IgA was detected in secretions and supernatants from gut fragment cultures. Furthermore, antigen specific CD4(+) cells were found in PP. Collectively these results suggest that the DNA vaccine stimulated a response in the PP, a major inductive site for mucosal responses.

IL-12 gene as a DNA vaccine adjuvant in a herpes mouse model: IL-12 enhances Th1-type CD4+ T cell-mediated protective immunity against herpes simplex virus-2 challenge.

IL-12 has been shown to enhance cellular immunity in vitro and in vivo. Recent reports have suggested that combining DNA vaccine approach with immune stimulatory molecules delivered as genes may significantly enhance Ag-specific immune responses in vivo. In particular, IL-12 molecules could constitute an important addition to a herpes vaccine by amplifying specific immune responses. Here we investigate the utility of IL-12 cDNA as an adjuvant for a herpes simplex virus-2 (HSV-2) DNA vaccine in a mouse challenge model. Direct i.m. injection of IL-12 cDNA induced activation of resting immune cells in vivo. Furthermore, coinjection with IL-12 cDNA and gD DNA vaccine inhibited both systemic gD-specific Ab and local Ab levels compared with gD plasmid vaccination alone. In contrast, Th cell proliferative responses and secretion of cytokines (IL-2 and IFN-gamma) and chemokines (RANTES and macrophage inflammatory protein-1alpha) were significantly increased by IL-12 coinjection. However, the production of cytokines (IL-4 and IL-10) and chemokine (MCP-1) was inhibited by IL-12 coinjection. IL-12 coinjection with a gD DNA vaccine showed significantly better protection from lethal HSV-2 challenge compared with gD DNA vaccination alone in both inbred and outbred mice. This enhanced protection appears to be mediated by CD4+ T cells, as determined by in vivo CD4+ T cell deletion. Thus, IL-12 cDNA as a DNA vaccine adjuvant drives Ag-specific Th1 type CD4+ T cell responses that result in reduced HSV-2-derived morbidity as well as mortality.