Presenting Author: Michael L Davies
, Scientist III at U.S. Army Med. Res. Inst. of Infectious Dis.
Abstract:
Yersinia pestis (Yp) is the etiological agent of plague, a disease that remains a concern as demonstrated by recent outbreaks in Madagascar. Infection with Yp results in a rapidly progressing illness that can only be treated with antibiotics. Live attenuated or whole-cell inactivated vaccines confer short-lived protection against bubonic but not pneumonic plague. Subunit vaccine formulations may circumvent some of these shortfalls. Here we compare the immunogenicity generated by the most advanced subunit vaccine (rF1V) against a nanolipoprotein particle (NLP)-based vaccine. BALB/c mice were immunized twice, four weeks apart. Four weeks later, splenocytes and sera were collected for immune profiling and mice were aerosol challenged with Yp CO92. Both formulations induced a strong IgG response against F1 and V proteins, along with a robust memory B cell response and cell-mediated response with Th1- and Th2-related cytokines. NLP-based vaccine induced a stronger cytokine response against F1, V, and F1V proteins relative to the rF1V vaccine. As with rF1V, the inclusion of Alhydrogel in NLP vaccine formulations was critical for enhanced immunogenicity and protective efficacy. Addition of Francisella tularensis antigens to the Yp NLP vaccine platform did not impair vaccine efficacy, based on protection and antibody response. The modularity and lipid bilayer structure of NLPs allows for incorporation of many protective antigens with variable ratios against multiple pathogens.