Nasopharyngeal-associated lymphoreticular tissue (NALT) immunity: Fimbriae-specific Th1 and Th2 cell-regulated IgA responses for the inhibition of bacterial attachment to epithelial cells and subsequent inflammatory cytokineproduction

To investigate the antibacterial activity of mucosal Th1 and Th2 immune res ponses induced nasally and orally, mice were immunized with mucosal vaccine containing fimbrial protein of Porphyromonas gingivalis, a causative agent for a destructive chronic inflammation in the periodontium, and cholera to xin (CT) as mucosal adjuvant. Nasal vaccine containing low doses of fimbria e (10 mu g) and CT (1 mu g) induced Ag-specific Th1/Th2-type response in CD 4(+) T cells in mucosal effector tissues, including nasal passage and subma ndibular glands, which accounted for the generation of Ag-specific IgA-prod ucing cells. In contrast, oral immunization required higher amounts of fimb riae and CT for the induction of Ag-specific IgA responses. Fimbriae-specif ic IgA mAbs generated from submandibular glands of nasally immunized mice i nhibited P, gingivalis attachment to and reduced subsequent inflammatory cy tokine production from epithelial cells. These findings suggest that nasal vaccination is an effective immunization regimen for the induction of Ag-sp ecific Th1 and Th2 cell-driven IgA immune responses that possess the abilit y to inhibit bacterial attachment to epithelial cells and subsequent inflam matory cytokine production.