title: Early, anti-immunoglobulin induced events prior to Na+-K+ pump activation: an analysis in a monoclonal human B-lymphoma cell population.
abstract: Events following F(ab)2 anti-delta immunoglobulin stimulation of monoclonal (leukemic) human B cells prior to Na+-K+ pump activation were investigated in vitro. This pump activation, measured by ouabain-sensitive 86Rb+ uptake, appeared susceptible to the phospholipid-interacting drugs tetracaine and quinacrine, to the antioxydant nordihydroguaiaretic acid (NDGA), and to the calmodulin antagonist trifluoperazine, while much less susceptible to the methylation inhibitor-3-deazaadenosine. The Ca++ ionophore A 23187 appeared to induce pump activation in a way similar to anti-delta, as it was susceptible to the same drugs and as anti-delta had no additional stimulating effect on A 23187-stimulated cells. However, whereas the anti-delta-induced activations appeared independent of the extracellular Ca++ activity, [Ca++]e, the activation by A 23187 was potentiated by addition of the Ca++ chelator ethyleneglycol-bis (beta-aminoethyl ether) N, N'-tetracetic acid (EGTA). Estimations by fluorescent chelator method (quin 2) showed anti-delta to increase the intracellular Ca++ activity, [Ca++]i both in the absence and presence of EGTA. A 23187 increased [Ca++]i strongly in Ca++ medium, but was weaker, more similar to the anti-delta response, in EGTA medium. It is suggested that Na+-K+ pump activation after anti-Ig stimulation in B cells may follow Ca++ mobilization from internal stores. The trifluoperazine susceptibility suggests that calmodulin regulation is involved.
mesh_terms: D000917:Antibody Formation; D000936:Antigen-Antibody Complex; D001402:B-Lymphocytes / Q000502:physiology*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000502:physiology; D006801:Humans; D008213:Lymphocyte Activation; D008223:Lymphoma; D008563:Membrane Lipids / Q000502:physiology; D008745:Methylation; D010741:Phospholipases A / Q000502:physiology; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D000936:Antigen-Antibody Complex; D002147:Calmodulin; D008563:Membrane Lipids; D011947:Receptors, Antigen, B-Cell; D014268:Trifluoperazine; D000001:Calcimycin; D010741:Phospholipases A; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium