Role of sarcolectin (SCL) and interferons in coordinated T cell clonal expansion.
T cell multiplication is attributed to the growth factor interleukin-2 (IL-2), which is, however, only activated when a specific cell membrane-bound receptor can be expressed. We found in all human sera tested a lectin that we described and called sarcolectin (SCL). SCL is a molecularly cloned 55-kDa protein that stimulates DNA synthesis in all immunocompetent cells and inhibits the interferon (IFN)-dependent antiviral state. SCL is excreted in conditioned medium of T cell cultures grown under serum-free conditions, where it can be demonstrated regularly by Western blots. In such cultures, in addition to SCL and IL-2, IFN-gamma and IFN-alpha also can be found, likely as a feedback response to DNA stimulation. Considered together, the data suggest that coordinated clonal expansion of T cells is governed by SCL-IL-2, both which induce T cell proliferation and simultaneously activate IL-2 receptors. T cell replication is downregulated by the effect of feedback IFN-gamma and IFN-alpha. To initiate a new growth cycle, SCL is thought to block the residual IFN-dependent antiproliferative state.
Kaba
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Université René Descartes-Paris V, Laboratoire des Interferons et de la Sarcolectine, Paris, France. akaba@infobiogen.fr
Ilunga
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LA
Chany
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C
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D002454:Cell Differentiation; D002455:Cell Division; D003429:Cross Reactions; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D006801:Humans; D007372:Interferons / Q000378:metabolism*; D037102:Lectins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D037102:Lectins; D010446:Peptide Fragments; C039495:sarcolectin; D007372:Interferons