No apparent influence of immunoglobulins on indigenous oral and intestinal microbiota of mice

The role of secretory immunoglobulin A (sIgA) in the control of the indigenous microbiota is not well understood. In this study, we compared the oral and intestinal microbiota of transgenic B cell-deficient (mu MT) mice with their heterozygous (mu MT/+) normal littermates. The levels of salivary IgA and serum IgA and IgG were normal in mu MT/+ mice, while no immunoglobulins were detected in mu MT/mu MT mice. The acquisition and proportions of the different species of the oral and intestinal indigenous bacterial populations were not significantly different between the two groups of mice. Our results thus suggest that secretory IgA does not play a major role in the regulation of the indigenous microbiota of mice.