Abstract
Mucosal immunization would provide an easy and safe measure in preventing infectious diseases by facilitating mass immunization. In order to represent a promising strategy for mucosal vaccination, oral, nasal, or sublingual immunizations of mice with a recombinant 40-kDa outer membrane protein of Porphyromonas gingivalis (r40k-OMP) and cholera toxin (CT) as a mucosal adjuvant were performed, and mucosal and systemic immune responses were compared. Administration of the antigen via the mucosal routes, such as orally, nasally or sublingually, equally elicited significant levels of r40k-OMP-specific IgG in the serum and high numbers of r40k-OMP-specific antibody-forming cells (AFCs) in the spleen. Nasal and sublingual immunization of mice also induced high levels of mucosal IgA antibodies (Abs) in the saliva and nasal washes compared to oral immunization. Subsequently, these immunizations confirmed the Ab titers by revealing significant numbers of r40k-OMP-specific AFCs in the submandibular glands, nasopharyngealassociated lymphoreticular tissue, and nasal passages. In contrast, mice that were orally immunized with r40k-OMP plus CT exhibited significantly increased antibody secreting cells in Peyerʼs patches and intestinal lamina propria, although lower level of cells were detected in nasal or sublingual immunization. These results have suggested that both nasal and sublingual immunization are more effective for prevention of periodontal disease compared to oral immunization.
