The impact of novel oral adjuvant dendritic fibrous nano-silica coated with M cell homing peptide-modified chitosan on enhancing both the intestinal mucosal and systemic immunity.

Oral vaccines, a major focus of contemporary vaccine research, still face critical challenges in achieving efficient antigen uptake and targeted delivery. M cells play a pivotal role in mediating antigen uptake and transport across the intestinal mucosa. To address these limitations, this study developed an oral adjuvant consisting of dendritic fibrous nanosilica coated with M cell homing peptide (CKS9)-modified chitosan (CKS9-CS-DFNSs). The resulting nanoparticles exhibited an average size of approximately 200 nm, a zeta potential of +27.1 mV, and a polydispersity index (PDI) of 0.29. Experimental results demonstrated that CKS9-CS-DFNSs could effectively target M cells, enhance antigen uptake in Peyer's patches (PPs), and increase the phagocytosis and activation of dendritic cells (DCs). Furthermore, compared with the CON group, CKS9-CS-DFNSs markedly stimulated T- and B-cell activation in PPs and mesenteric lymph nodes (MLNs) and promoted memory T-cell responses. Additionally, ELISA analysis revealed that CKS9-CS-DFNSs effectively increased the levels of BSA-specific IgG in serum and BSA-specific IgA in the intestine, as well as the level of sIgA in the intestine. These results indicate that CKS9-CS-DFNSs have the potential to serve as an oral delivery platform for enhancing the efficacy of oral vaccines.