Secretory IgA and serum IgA in human inflammatory gingiva were demonstrated by immunopathological observation. Secretory IgA localized in the dental plaque, on the surface of gingiva, in the interspace of gingival epithelium and partially in the cytoplasm of gingival epithelium whereas serum IgA existed in all portion of gingiva.
From above results, it was concluded that secretory IgA prevented oral bacterial invasion to the periodontal tissue by coating to them, and serum IgA raised bacterical lysis by complemental activation of thealternate pathway or enhanced phagocytosis of PMNLs.
