TY - JOUR
T1 - Mitogenic response of human thymocytes
T2 - Identification of functional Ca2+-dependent and independent signals
AU - Roifman, C. M.
AU - Mills, G. B.
AU - Cheung, R. K.
AU - Gelfand, E. W.
PY - 1986
Y1 - 1986
N2 - In contrast to peripheral blood mononuclear cells (PBMC), human thymocytes do not exhibit a proliferative response to the T cell mitogens phytohaemagglutinin (PHA), concanavalin A (Con A), or Staphylococcal protein A (SPA). In thymocytes and PBMC, Con A and PHA induce increases in free cytosolic calcium concentrations ([Ca2+](i)). Since both Con A and PHA induce similar increases in [Ca2+](i) in thymocytes and PBMC, the absence of thymocyte proliferation was not due to an inability to induce an increase in [Ca2+](i). The lack of a proliferative response was secondary to the failure of the mitogens to induce interleukin 2 (IL-2) production. Incubation of mitogen-treated thymocytes with phorbol esters reconstituted IL-2 production and the proliferative response indicating that the cells were indeed activated by the mitogens. Similarly, addition of exogenous recombinant IL-2 also induced mitogen-treated thymocytes to proliferate. This IL-2-dependent proliferation established that SPA, Con A, and PHA triggered the expression of biologically active IL-2 receptors. Since an increase in [Ca2+](i) is a prerequisite, and possibly a trigger, for IL-2 production, the failure of PHA, Con A, or SPA to result in thymocyte proliferation may be due to an inability of thymocytes to respond to increases in [Ca2+ ](i) with subsequent IL-2 production.
AB - In contrast to peripheral blood mononuclear cells (PBMC), human thymocytes do not exhibit a proliferative response to the T cell mitogens phytohaemagglutinin (PHA), concanavalin A (Con A), or Staphylococcal protein A (SPA). In thymocytes and PBMC, Con A and PHA induce increases in free cytosolic calcium concentrations ([Ca2+](i)). Since both Con A and PHA induce similar increases in [Ca2+](i) in thymocytes and PBMC, the absence of thymocyte proliferation was not due to an inability to induce an increase in [Ca2+](i). The lack of a proliferative response was secondary to the failure of the mitogens to induce interleukin 2 (IL-2) production. Incubation of mitogen-treated thymocytes with phorbol esters reconstituted IL-2 production and the proliferative response indicating that the cells were indeed activated by the mitogens. Similarly, addition of exogenous recombinant IL-2 also induced mitogen-treated thymocytes to proliferate. This IL-2-dependent proliferation established that SPA, Con A, and PHA triggered the expression of biologically active IL-2 receptors. Since an increase in [Ca2+](i) is a prerequisite, and possibly a trigger, for IL-2 production, the failure of PHA, Con A, or SPA to result in thymocyte proliferation may be due to an inability of thymocytes to respond to increases in [Ca2+ ](i) with subsequent IL-2 production.
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M3 - Article
C2 - 3100117
AN - SCOPUS:0022472392
SN - 0009-9104
VL - 66
SP - 139
EP - 149
JO - Clinical and Experimental Immunology
JF - Clinical and Experimental Immunology
IS - 1
ER -