Stimulation of gut-associated lymphoid cells by IL-4 and B-cell growth factor II.

We have analysed the ability of B cells isolated from the Peyer's patches of normal mice to respond to two different B-cell stimulatory factors. Peyer's patch B cells respond in vitro to co-stimulation by either interleukin-4 (IL-4) plus anti-IgM or B-cell growth factor II (BCGF-II) plus dextran sulphate (DXS). We have consistently observed that splenic B cells proliferate more than Peyer's patch B cells when co-stimulated by BCGF-II plus DXS. This is not due to a diminished proliferation capacity of the Peyer's patch B-cell preparations, because the Peyer's patch B cells often proliferate more than splenic B cells when co-stimulated with IL-4 plus anti-IgM. These differences are not a result of altered response kinetics or differences in relative amounts of surface IgM on the two types of B cells. We have also analysed B cells from the LPS hypo-responsive strain C3H/HeJ, and its LPS responsive partner strain C3H/OuJ, from the X-linked immunodeficient strain (xid), CBA/N, and from germ-free (GF) mice. B cells from spleens and Peyer's patches of GF mice are responsive to co-stimulation by IL-4 plus anti-IgM and to co-stimulation by BCGF-II plus DXS. Peyer's patch B cells from C3H/HeJ mice proliferate as well as Peyer's patch B cells from C3H/OuJ cells to both co-stimulation protocols. Among the types of B cells studied here, only cells from spleens and Peyer's patches of mice that bear the xid defect fail to respond to the signals delivered by lymphokine co-stimulation. Our results suggest that while Peyer's patch B cells are stimulated by these two lymphokines, Peyer's patches contain cells that react differently from spleen cells to either the lymphokines IL-4 and BCGF-II, or the co-stimulators anti-IgM or dextran sulphate.