Pilot Study on the Use of DNA Priming Immunization to Enhance Y. pestis LcrV-Specific B Cell Responses Elicited by a Recombinant LcrV Protein Vaccine.

Recent studies indicate that DNA immunization is powerful in eliciting antigen-specific antibody responses in both animal and human studies. However, there is limited information on the mechanism of this effect. In particular, it is not known whether DNA immunization can also enhance the development of antigen-specific B cell development. In this report, a pilot study was conducted using plague LcrV immunogen as a model system to determine whether DNA immunization is able to enhance LcrV-specific B cell development in mice. Plague is an acute and often fatal infectious disease caused by Yersinia pestis (Y. pestis). Humoral immune responses provide critical protective immunity against plague. Previously, we demonstrated that a DNA vaccine expressing LcrV antigen can protect mice from lethal mucosal challenge. In the current study, we further evaluated whether the use of a DNA priming immunization is able to enhance the immunogenicity of a recombinant LcrV protein vaccine, and in particular, the development of LcrV-specific B cells. Our data indicate that DNA immunization was able to elicit high-level LcrV antibody responses when used alone or as part of a prime-boost immunization approach. Most significantly, DNA immunization was also able to increase the levels of LcrV-specific B cell development. The finding that DNA immunization can enhance antigen-specific B cell responses is highly significant and will help guide similar studies in other model antigen systems.