Kinetics of local immune responses in mouse Peyer's patches after respiratory exposure to flour

Peyer's patches play a major role in the initiation of mucosal immune responses since most environmental antigens gain access to the digestive tract and are therefore liable to achieve contact with their specialized dome epithelium. We investigated kinetics of immunophenotypic modifications induced in the cells from murine Peyer's patches in a model of intensive controlled exposure to flour dust. Three groups of mice were placed in an atmosphere enriched in wheat flour for 3, 6 or 10 consecutive days. Although Ig bearing B cell numbers did not vary, the numbers of IgA-containing plasma-cells increased significantly during the course of exposure. A significant and increasing imbalance of the CD4/CD8 ratio was noted, as early as after 3 days of exposure related both to increasing numbers of CD4 + and decreasing numbers of CD8 + cells. These data indicate a rapid kinetics of immune responses in Peyer's patches in an original model of controlled respiratory challenge.