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CD4(+) and CD8(+) T cell survival is regulated differentially by protein kinase C theta, c-Rel, and protein kinase B


Saibil, SD; Jones, RG; Deenick, EK; Liadis, N; Elford, AR; Vainberg, MG; Baerg, H; Woodgett, JR; Gerondakis, S; Ohashi, PS
2007-03-01
JOURNAL OF IMMUNOLOGY
Journal Article
178
5
2932-2939
An effective immune response requires the expansion and survival of a large number of activated T cells. This study compared the role of protein kinase C (PKC)theta and associated signaling molecules in the survival of activated primary CD4(+) vs CD8(+) murine T cells. We demonstrate that the absence of PKC theta resulted in a moderate survival defect in CD4(+) T cells and a striking survival defect of CD8(+) T lymphocytes. CD8(+) T cells lacking the c-Rel, but not the NF-kappa B1/p50, member of the NF-kappa B family of transcription factors displayed a similar impairment in cell survival as PKC theta(-/-) CD8(+) T lymphocytes. This implicates c-Rel as a key target of PKC theta-mediated survival signals in CD8(+) T cells. In addition, both c-Rel(-/-) and PKC theta(-/-) T cells also displayed impaired expression of the antiapoptotic Bcl-x(L) protein upon activation. Changes in Bcl-x(L) expression, however, did not correlate with the survival of CD4(+) or CD8(+) lymphocytes. The addition of protein kinase B-mediated survival signals could restore partially CD4(+) T cell viability, but did not dramatically influence CD8(+) survival. Active protein kinase B was also unable to restore proliferative responses in CD8(+) PKC theta(-/-) IF cells. The survival of CD4(+) and CD8(+) T cells deficient in either PKC theta or c-Rel, however, was promoted by the addition of IL-2. Collectively, these data demonstrate that CD4(+) and CD8(+) T cell survival signals are differentially programmed.
AMER ASSOC IMMUNOLOGISTS
NF-KAPPA-B; BCL-X-L; FORKHEAD TRANSCRIPTION FACTOR; IN-VIVO; PKC-THETA; LYMPHOCYTE-PROLIFERATION; CYCLE PROGRESSION; UP-REGULATION; ACTIVATION; EXPRESSION
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