The amount of secreted IgA may not determine the secretory IgA coating ratio of gastrointestinal bacteria |
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| Authors: | Takeshi Tsuruta,Ryo Inoue,Iyori Nojima,Takamitsu Tsukahara,Hiroshi Hara,& Takaji Yajima |
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| Affiliation: | Laboratory of Nutritional Biochemistry, Department of Bioscience and Chemistry, Faculty of Agriculture, Hokkaido University, Sapporo, Japan;;Meiji Dairies Research Chair, Creative Research Initiative Sousei (CRIS), Hokkaido University, Sapporo, Japan;and;Kyoto Institute of Nutrition and Pathology, Furuikedani, Uji-tawara, Kyoto, Japan |
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| Abstract: | It is reported that some, but not all, bacteria in human faeces are coated with secretory immunoglobulin A (S-IgA). We evaluated the proportion of S-IgA-coated bacteria to total intestinal bacteria (S-IgA coating ratio) in the gastrointestinal tract of two different strains of mice supplied by two different suppliers. The S-IgA coating ratio was significantly different in each gastrointestinal segment and between mouse suppliers. The amount of non-bacteria-bound IgA (free IgA) in each gastrointestinal segment indicated that this difference in the S-IgA coating ratio might not be due to the amount of secreted IgA. Furthermore, immunoblotting analysis revealed that only a small amount of IgA (<5% to free-IgA) was used for the coating. This indicates that, although sufficient S-IgA was secreted to coat the entire intestinal population of bacteria, only some part of the bacteria were coated with S-IgA. This study suggests that the amount of luminal S-IgA may not determine the S-IgA coating ratio, and that the amount of IgA coating intestinal commensal bacteria is very small. |
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| Keywords: | secretary immunoglobulin A commensal intestinal bacteria IgA concentration |
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