title: In vivo and in vitro expression of an interleukin 2 receptor by murine B and T lymphocytes.
abstract: Interleukin 2 (IL 2), which is well established to be a T cell growth factor, has more recently been shown to stimulate B lymphocyte growth and differentiation in vitro. Responsiveness of B and T cells to IL 2 has been associated with expression of a cell membrane IL 2 receptor (IL 2R). To investigate the role of IL 2 in B cell growth and differentiation in vivo, a system was used in which the injection of mice with a goat antibody to mouse IgD (GaM delta) induces polyclonal T-independent B cell proliferation first, and later induces polyclonal T-dependent B cell proliferation and IgG secretion. IL 2R expression by splenic B and T lymphocytes from GaM delta injected mice was studied by a dual label immunofluorescence technique. Although GaM delta was found to be a strong inducer of B cell IL 2R expression in vitro, even in serum-free medium, and stimulated up to 50% of splenic T cells to express considerable quantities of IL 2R in vivo, it failed to induce more than minimal B cell IL 2R expression in vivo. Concanavalin A and bacterial lipid A also induced B cells to express IL 2R to a much greater extent in vitro than in vivo. Although these agents and GaM delta acted synergistically to stimulate B cell IL 2R expression both in vitro and in vivo, a single agent induced B cell IL 2R expression to a considerably greater extent in vitro than did all three agents acting together in vivo. In vitro GaM delta-induced B cell IL 2R expression was not suppressed by inclusion of IL 2 in the culture medium but was suppressed by the presence of 10% normal mouse serum or plasma. These observations suggest that polyclonal T-dependent B cell proliferation and antibody secretion may not require an interaction between B cells and IL 2; the in vivo environment may downregulate IL 2R expression by B cells: and in vivo B cell IL 2R expression and consequently, induction of B cell responsiveness to IL 2, may require stimuli beyond those sufficient to induce B cell IL 2R expression and IL 2 responsiveness in vitro.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D007072:Immunoglobulin D / Q000276:immunology; D007376:Interleukin-2 / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D011971:Receptors, Immunologic / Q000378:metabolism*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007072:Immunoglobulin D; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2