TY - JOUR

T1 - Signal transduction by HLA class II antigens expressed on activated T cells

AU - Ødum, Niels

AU - Martin, P J

AU - Schieven, G L

AU - Hansen, J A

AU - Ledbetter, J A

N1 - Keywords: Antigens, CD4; Antigens, CD7; Antigens, Differentiation, T-Lymphocyte; Calcium; Cell Compartmentation; Enzyme Activation; HLA-D Antigens; Humans; Lymphocyte Activation; Lymphocyte Specific Protein Tyrosine Kinase p56(lck); Phosphoproteins; Phosphotyrosine; Protein-Tyrosine Kinases; Receptor Aggregation; Receptors, Immunologic; Signal Transduction; T-Lymphocytes; Tyrosine

PY - 1991

Y1 - 1991

N2 - Human T cells express HLA class II antigens upon activation. Although activated, class II+ T cells can present alloantigens under certain circumstances, the functional role of class II antigens on activated T cells remains largely unknown. Here, we report that cross-linking of HLA-DR molecules expressed on allospecific, CD4+ T clones and cell lines can function as transduction elements that trigger rapid cellular responses including tyrosine phosphorylation of cellular proteins and mobilization of Ca2+ from internal stores. The proteins phosphorylated on tyrosine were distinct from those observed after cross-linking CD4. Ligation of CD4 and class II molecules generated a synergistic effect of the intracellular free Ca2+ concentration response that required an interaction between the molecules on the cell surface. Since class II is the natural ligand for CD4, the present data suggest that class II is induced on activated T cells to regulate CD4 function, possibly by specific interaction with the CD4-associated p56lck protein tyrosine kinase.

AB - Human T cells express HLA class II antigens upon activation. Although activated, class II+ T cells can present alloantigens under certain circumstances, the functional role of class II antigens on activated T cells remains largely unknown. Here, we report that cross-linking of HLA-DR molecules expressed on allospecific, CD4+ T clones and cell lines can function as transduction elements that trigger rapid cellular responses including tyrosine phosphorylation of cellular proteins and mobilization of Ca2+ from internal stores. The proteins phosphorylated on tyrosine were distinct from those observed after cross-linking CD4. Ligation of CD4 and class II molecules generated a synergistic effect of the intracellular free Ca2+ concentration response that required an interaction between the molecules on the cell surface. Since class II is the natural ligand for CD4, the present data suggest that class II is induced on activated T cells to regulate CD4 function, possibly by specific interaction with the CD4-associated p56lck protein tyrosine kinase.

M3 - Journal article

C2 - 1703961

VL - 21

SP - 123

EP - 129

JO - European Journal of Immunology

JF - European Journal of Immunology

SN - 0014-2980

IS - 1

ER -