Expression of IL-5 receptors on B cells: role in mucosal B cell responses.

IL-5 plays an important role in mucosal B cell responses. An in vitro model of IgA B cell differentiation, CH12LX, has been used to demonstrate that IL-5R are expressed on both IgM+ and IgA+ B cells and that IL-5 will enhance secretion of both IgM and IgA by CH12LX B cells, depending on the surface isotype of individual cells. Further, the enhanced secretion of Ig in response to IL-5 is associated with increased steady-state levels of Ig mRNA. Finally, normal Peyer's patch B cells are also capable of expressing IL-5R in response to appropriate stimuli (i.e. anti-IgM- or anti-IgD-dextran). Thus, mucosal B cell responses to IL-5 are brought about by interaction of IL-5 with specific receptors expressed on the surface of those cells.