Specific ganglioside binding to receptor sites on T lymphocytes that couple to ganglioside-induced decrease of CD4 expression

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摘要：

The binding of different gangliosides to rat T-helper lymphocytes was characterized under conditions that decrease CD4 expression on different mammalian T-helper lymphocytes. Saturation binding by monosialylated [ 3H]-GM 1 to rat T-lymphocytes was time- and temperature-dependent, had a dissociation constant (K D) of 2.2 ± 1.4 μM and a binding capacity near 2 fmoles/cell. Competitive inhibition of [ 3H]-GM 1 binding demonstrated a structural-activity related to the number of unconstrained sialic acid moieties on GM 1-congeneric gangliosides. A comparison between the results of these binding studies and ganglioside-induced decrease of CD4 expression demonstrated that every aspect of [ 3H]-GM 1 binding concurs with gangliosides modulation of CD4 expression. It is concluded that the specific decrease of CD4 expression induced by pretreatment with gangliosides involves the initial process of ganglioside binding to specific sites on CD4 -+ T-helper lymphocytes.

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关键词：

basic biological sciences gangliosides biochemical reaction kinetics lymphocytes receptors rats temperature dependence time dependence tracer techniques tritium compounds