In vitro and in vivo evaluation of immune response of poly(lactic acid) nanoparticles with different end groups

Poly(lactic acid) (PLA) has excellent properties of biodegradability and biocompatibility, which is a US Food and Drug Administration (FDA) approved biopolymer for the preparation of safe and effective vaccines, drugs, and gene delivery systems. However, there still exists a great problem whether and how the end group affects the immune response of PLA vaccines. Therefore, the aim of this study was to evaluate the in vitro and in vivo of immune response of PLA nanoparticles (NPs) with carboxyl (COOH) and ester (COOR) end groups. In vitro experiments suggested COOH NPs could promote the higher phagocytosis and activation of bone marrow dendritic cells (BMDCs) with a lower cytotoxicity. In vivo experiments showed that COOR NPs and COOH NPs could strongly elicit IgG, IgG1, and IgG2a responses both in the short and long-terms. However, the highest T cell and B cell activation, and central memory T cells response was induced by COOH NPs. In addition, the COOH NPs could significantly enhance splenocytes proliferation and cytokines secretion. Thus, the PLA with the COOH end group shows greater potential as efficient carrier materials of NPs for enhancing cellular and humoral immune responses.

Automated summary

This study evaluated the immune response of poly(lactic acid) (PLA) nanoparticles with different end groups. In vitro experiments showed that carboxyl (COOH) end group nanoparticles could promote the activation of bone marrow dendritic cells with lower cytotoxicity. In vivo experiments demonstrated that both COOH and ester (COOR) end group nanoparticles could elicit immune responses, but COOH end group nanoparticles induced stronger T cell and B cell activation as well as central memory T cell response, and significantly enhanced splenocyte proliferation and cytokine secretion.