PLA-PEG nanoparticles are suitable for effective maturation and uptake by dendritic cells for Chlamydia trachomatis outer membrane peptide-based vaccine

摘要

Chlamydia trachomatis is considered an important human pathogen because it is the most reported sexually transmitted bacterial infection globally. We showed that M278 (a peptide derived from the major outer membrane protein of C. trachomatis) encapsulated within poly (lactic acid)-b-Poly (ethylene glycol) (PLA-PEG) nanoparticles (NPs) triggered enhanced systemic adaptive immune responses in mice. PLA-PEG can facilitate passive uptake of antigens by dendritic cells (DCs) by increasing the influx of DCs in to the injection site. Therefore, in this study, we investigated the potential of PLA-PEG-encapsulated M278 NPs to induce maturation and activation of DCs for effective antigen presentation to bolster immune responses. DCs were derived from mouse bone marrow cells and exposed to of 2.5 μg/mL of naked M278 or encapsulated M278 for 24 hours to determine the expressions of costimulatory molecules (CD80 and CD86) and the MHC complex. Results from flow cytometry and immunofluorescence microscopy revealed that encapsulated M278 enhanced the expression levels of CD80, CD86, CD40 and MHC complex on DCs as compared to naked M278, suggesting that NPs were more efficiently processed by DCs. Collectively, these data suggests that our nano-encapsulated M278 vaccine drives maturation of DCs and efficient antigen presentation for elicitation of enhanced Thl adaptive immune responses.