Open AccessHuman salivary aggregation in Streptococcus intermedius type g strains: relationship with IgA
Author(s) -
Yamaguchi Taihei
Publication year - 2004
Publication title -
fems immunology & medical microbiology
Language(s) - English
Resource type - Journals
eISSN - 1574-695X
pISSN - 0928-8244
DOI - 10.1016/j.femsim.2004.01.008
Subject(s) - saliva , agglutinin , biology , microbiology and biotechnology , sepharose , bacteria , streptococcus , size exclusion chromatography , lectin , biochemistry , enzyme , genetics
Bacterial aggregation is an important step in elimination from the human body to protect against infection. Streptococcus intermedius K1K aggregates in human saliva. In this study, the salivary agglutinin was identified. The aggregation level was very strong in sonic‐treated saliva and 1‐μm filtrate. Preincubation of human saliva with anti‐human α chain serum or anti‐human whole saliva serum completely inhibited aggregation, but preincubation with anti‐human μ chain serum or anti‐Fc fragment of human IgG serum had no effect. Agglutinin of human saliva that could aggregate the strain K1K was purified using DEAE–Sepharose CL‐6B, Phenyl–Sepharose CL‐4B and Sephacryl S200HR gel filtration. Purified salivary agglutinin was characterized with electrophoresis and immunological techniques, indicating that purified material was IgA. Bacterial aggregation was dependent on the presence of calcium. Saliva filtrate specimens from eight healthy men and eight women showed different aggregation activities. Three men and one woman had little activity. These data show that the present bacterial aggregation was an immunoreaction between IgA in saliva and the bacteria dependent on the levels of calcium. In addition, the IgA in human saliva related with possible calcium‐dependent antigen(s) on the surface of strain K1K.