Modulation of innate and adaptive immunity by biodegradable nanoparticles.

Vaccine strategy needs efficient adjuvants to induce potent antigen-specific immune responses by targeting antigens to antigen presenting cells followed by their functional maturation. In this study, biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs) were examined for their immunological activities in mice. Like lipopolysaccharide, gamma-PGA NPs strongly activated spleen dendritic cells (DCs) and induced their cytokine production and costimulatory molecule expression through the nuclear factor-kappaB and mitogen-activated protein kinase signaling pathways. The immunization of mice with ovalbumin-carrying gamma-PGA NPs could induce the antigen-specific and long-lived effector and central memory CD8(+) T cells as well as antibody responses. Thus, gamma-PGA NPs have great potential as an efficient antigen carrier and strong adjuvant to DCs.