title: Recombinant human CD40 ligand stimulates B cell proliferation and immunoglobulin E secretion.
abstract: Signaling through the cell surface molecule, CD40, is known to play an important role in the proliferation and differentiation of B lymphocytes. Using the thymoma cell line EL4, we recently identified and cloned a cDNA encoding a murine ligand for the CD40 molecule (mCD40-L) and showed that it has biological activity in vitro. A cDNA encoding a human homologue of the mCD40-L was isolated using crosshybridization techniques from an activated peripheral blood T cell library. The predicted amino acid sequence indicates that this human ligand for CD40 (hCD40-L) is a 261 amino acid type II membrane protein that exhibits 78% amino acid identity with its murine counterpart. Northern blot and FACS analyses suggest that the hCD40-L is restricted in its expression to T lymphocytes, and that it is most abundant on the CD4+ T cell subpopulation. Cells transfected with hCD40-L caused the proliferation of human tonsil B cells in the absence of costimuli and, in the presence of interleukin 4, induced immunoglobulin E secretion from purified human B cells. A comparison of the efficacy of the hCD40-L and mCD40-L in these assays is presented.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism / Q000502:physiology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D019013:CD40 Antigens; D023201:CD40 Ligand; D002478:Cells, Cultured; D003001:Cloning, Molecular; D006801:Humans; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000378:metabolism*; D015847:Interleukin-4 / Q000494:pharmacology; D007700:Kinetics; D008213:Lymphocyte Activation; D008223:Lymphoma; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000276:immunology; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D019013:CD40 Antigens; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D023201:CD40 Ligand; D015847:Interleukin-4; D007073:Immunoglobulin E