title: Polyclonal activation of murine B lymphocytes by Fc fragments. I. The requirement for two signals in the generation of the polyclonal antibody response induced by Fc fragments.
abstract: Fc fragments derived from human IgG1 induce murine splenic B lymphocytes to undergo proliferation and differentiation to antibody-secreting cells. The polyclonal antibody response was found to require both the presence of macrophages and T cells. Spleen cell cultures from nude mice or T cell-depleted normal mice proliferate to the level of untreated control mice but do not produce polyclonal antibody unless T cells are added. Regulation of the Fc fragment induced B cell differentiation to antibody synthesis apparently occurs through two distinct signals. One signal is provided by Fc fragments for proliferation and the other by T cells for differentiation. This suggestion is supported by the observation that spleen cell preparations, devoid of T cells, are capable of proliferation to the level of normal spleen cell cultures in response to Fc fragments, but are incapable of making a polyclonal antibody response. The cell population that responds to the differentiation signal also responds to the proliferative signal. "Hot pulse" experiments demonstrated that proliferation precedes polyclonal activation.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D002999:Clone Cells / Q000276:immunology; D006801:Humans; D007141:Immunoglobulin Fc Fragments; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D011817:Rabbits; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D007141:Immunoglobulin Fc Fragments; D014301:Trinitrobenzenes