Early intracellular events in human T cells induced by anti-Leu4 antibody: comparison between responders and nonresponders.
Early intracellular signals in response to anti-Leu4 in T cells were studied. There are two groups whose T cells, in the presence of accessory cells, proliferate (responders) or not (nonresponders) in response to anti-CD3 antibodies of the subclass IgG1, as is the case with anti-Leu4. Approximately 30% of Protein Kinase C (PKC) in the cytosol fraction disappeared temporarily, thereby indicating PKC activation, in response to immobilized anti-Leu4. PKC activation in purified T cells was detected both in responders and in nonresponders. The stimulation by anti-Leu4 crosslinked with goat anti-mouse IgG led to an increase in intracellular free calcium concentration [Ca++]i) in the T cells, and this increase was identical in responders and nonresponders. Although minimal Interleukin 2 (IL-2) receptor expression was apparent, T cells even from responders failed to proliferate in response to anti-Leu4, in the absence of accessory cells. Thus, in T cells from responders or nonresponders, anti-Leu4 stimulation induces early intracellular signal transduction and IL-2 receptor expression, but without accessory cells, proliferation does not occur.
Tada
Y
Y
First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Nagasawa
K
K
Yamauchi
Y
Y
Niho
Y
Y
Kaneoka
H
H
D000328:Adult; D000906:Antibodies / Q000008:administration & dosage; D000943:Antigens, Differentiation; D002118:Calcium / Q000378:metabolism; D002455:Cell Division; D004789:Enzyme Activation; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D011493:Protein Kinase C / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
D000906:Antibodies; D000943:Antigens, Differentiation; D015375:Receptors, Interleukin-2; D011493:Protein Kinase C; D002118:Calcium