We previously developed a Chlamydia trachomatis nanovaccine (PPM) by encapsulating a chlamydial M278 peptide within poly(lactic acid)-poly(ethylene glycol) biodegradable nanoparticles that immunopotentiated Chlamydia-specific immune effector responses in mice. Herein, we investigated the mechanistic interactions of PPM with mouse bone marrow-derived dendritic cells (DCs) for its uptake, trafficking, and T-cell activation. Our results reveal that PPM triggered enhanced expression of effector cytokines and chemokines, surface activation markers (Cd1d2, Fcgr1), pathogen-sensing receptors (TLR2, Nod1), co-stimulatory (CD40, CD80, CD86) and MHC class I and II molecules. Co-culturing of PPM-primed DCs with T cells from C. muridarium vaccinated mice yielded an increase in Chlamydia-specific immune effector responses including CD3⁺ lymphoproliferation, CD3⁺CD4⁺ IFN-γ-secreting cells along with CD3⁺CD4⁺ memory (CD44^highand CD62^high) and effector (CD44^high and CD62^low) phenotypes. Intracellular trafficking analyses revealed an intense expression and colocalization of PPM predominantly in endosomes. PPM also upregulated the transcriptional and protein expression of the endocytic mediator, caveolin-1 in DCs. More importantly, the specific inhibition of caveolin-1 led to decreased expression of PPM-induced cytokines and co-stimulatory molecules. Our investigation shows that PPM provided enhancement of uptake, probably by exploiting the caveolin-mediated endocytosis pathway, endosomal processing, and MHC II presentation to immunopotentiate Chlamydia-specific immune effector responses mediated by CD4⁺ T cells.

我们之前通过将衣原体M278肽封装在可增强小鼠免疫力的衣原体特异性免疫效应应答的聚乳酸-聚乙二醇可生物降解的纳米颗粒内，开发了沙眼衣原体纳米疫苗（PPM）。本文中，我们研究了PPM与小鼠骨髓来源的树突状细胞（DC）的吸收，运输和T细胞活化的机制相互作用。我们的研究结果表明PPM触发了效应细胞因子和趋化因子，表面活化标记（Cd1d2，Fcgr1），病原体敏感受体（TLR2，Nod1），共刺激（CD40，CD80，CD86）和MHC I和II类分子的表达增强。PPM引发的DC与毛C衣藻T细胞的共培养接种疫苗的小鼠产生了衣原体特异性免疫效应反应，包括CD3 ⁺淋巴增生，CD3 ⁺ CD4 ⁺ IFN-γ分泌细胞，以及CD3 ⁺ CD4 ⁺记忆（CD44^高和CD62^高）和效应子（CD44^高和CD62^低）表型。细胞内运输分析表明，PPM主要在内涵体中强烈表达和共定位。PPM还上调了DC中内吞介体小窝蛋白1的转录和蛋白表达。更重要的是，caveolin-1的特异性抑制导致PPM诱导的细胞因子和共刺激分子表达降低。我们的研究表明，PPM可能通过利用空洞蛋白介导的内吞途径，内体加工和MHC II呈递来增强CD4 ⁺ T细胞介导的衣原体特异性免疫效应反应，从而提高了摄取。