title: Growth of single B cell clones is enhanced by products of a T cell line.
abstract: In this paper we show the presence of a B cell growth-promoting activity in T cell replacing factor (TRF) supernatants from a monoclonal T cell line and polyclonally activated splenic T cells. The target cell of this activity is indisputably shown to be the B cell, which indicates that T cell-derived factors can act directly on B cells. The effect of monoclonal TRF-containing supernatant from the C.C3.11.75 Dennert cell line, (DL)TRF, which demonstrates B cell growth-promoting activity, is to increase the frequency of B cell clones stimulated by mitogens as opposed to increasing B cell clone sizes. (DL)TRF B cell growth enhancement is observed when B cells are activated by fetal calf serum mitogens, lipopolysaccharide (LPS), dextran sulfate (DXS), or LPS + DXS. The growth-promoting activity of (DL)TRF appears to be that of a costimulator rather than a classical growth factor because (DL)TRF alone is not sufficient to maintain clonal growth of activated B lymphoblasts.
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D002455:Cell Division; D002478:Cells, Cultured; D002999:Clone Cells; D015848:Interleukin-5; D008222:Lymphokines / Q000494:pharmacology*; D008934:Mitogens / Q000494:pharmacology; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D000276:Adjuvants, Immunologic; D015848:Interleukin-5; D008222:Lymphokines; D008934:Mitogens