(386f) Induction of T Cell Responses By pH-Responsive Blend Polymer Particle Protect Against Herpes Simplex Virus 2 Infection

Varied kinds of vaccines have been developed for mucosal-derived viral infections, such as herpes simplex virus, in decades. Lacking of sufficient cellular immunity, candidate HSV-2 vaccines that were protective in animal model, however, have not been successful in human clinical studies. Vaccines that can generate a broad spectrum of immune responses are expected to be more effective than those that generate humoral responses alone. In this study, a pH-responsive blend polymer particle, made of poly(lactic-co-glycolic acid) (PLGA) and two random pH-sensitive copolymer, has been developed.  With optimized composition, this blend particle showed the ability to elicit higher level of T cell responses and comparable level of humoral responses in comparison with aluminum hydroxide adjuvant. By using with a novel mucosal vaccination strategy developed in our lab, this particle system was tested to protect mice from genital HSV-2 infection. The results suggested that T cell immune responses play an important role for the protection against HSV-2. Additionally, this pH-responsive blend particle system provides an insight for vaccine development against HSV-2 infections.