Contribution of p56lck to the upregulation of cytokine production and T cell proliferation by IL-2 in human CD3-stimulated T cell clones.
Interaction of the interleukin 2 receptor (IL-2R) beta chain with the lymphocyte-specific protein tyrosine kinase (PTK), p56lck, has led to the speculation that p56lck participates in growth signal transduction. Although activation of T cells with interleukin 2 (IL-2) results in the activation of p56lck, accumulating data support the notion that Lck does not play an essential role in mitogenic signal delivery from the IL-2R. Since this src-related PTK has been shown to enhance TCR/CD3-mediated T cell responsiveness, here we investigated whether activation of Lck by IL-2 could contribute to enhance TCR/CD3-mediated T cell functions. This was achieved by using human CD4(+)-cloned T cells and comparing the effects of IL-2 on p56lck kinase activation and cytokine production. Results show that p56lck kinase activity increased as early as 1 min, reached a maximum within 5 min and decreased within 60 min after IL-2 stimulation. Such treatment with IL-2 also resulted in enhancing T cell responsiveness to CD3+PMA stimulation, as assessed by IL-2 and IFN-gamma secretion and by T cell proliferation. This increase of T cell functions was correlated with IL-2-induced p56lck activation in both dose-response and time-course experiments. Taken together these results strongly suggest that activation of Lck by IL-2 may play a role in regulating CD3-mediated T cell functions.
Eljaafari
A
A
INSERM CJF 90-15, Developpement et maturation du Systeme immunitaire, Hopital Robert-Debré, Paris, France.
Dorval
I
I
Soula
M
M
Quelvennec
E
E
Pirenne
H
H
Fagard
R
R
Sterkers
G
G
D017252:CD3 Complex / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002999:Clone Cells; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D007376:Interleukin-2 / Q000502:physiology*; D008213:Lymphocyte Activation / Q000276:immunology*; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000276:immunology*; D011518:Proto-Oncogene Proteins / Q000276:immunology; D051076:Proto-Oncogene Proteins c-fyn; D013601:T-Lymphocytes / Q000276:immunology*; D015854:Up-Regulation / Q000276:immunology
D017252:CD3 Complex; D016207:Cytokines; D007376:Interleukin-2; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494957:FYN protein, human; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D051076:Proto-Oncogene Proteins c-fyn