RESUMO
Recently published reports suggest that the activation of protein kinase C (PKC) plays an important role in the activation pathway of many cell types. In this study, we examined the role of PKC in human T-cell proliferation, IL-2 production, and IL-2R expression, when cultured with the mitogen PHA, the PKC inhibitor H-7, and H-7 control HA1004. H-7 inhibited the PHA-stimulated [3H]thymidine uptake, IL-2 production, and IL-2R expression in a dose-related manner. Further, we found H-7 inhibited T-cell proliferation, IL-2 production, IL-2 mRNA from PHA plus PMA-stimulated cultures. We also found that H-7 inhibited the early-stage activation of PHA-stimulated cells. The presence of exogenous purified human IL-2 or rIL-4 partly reversed the immunosuppression caused by H-7. In contrast, HA1004 had no effect on cell proliferation, IL-2 production, or IL-2R expression. Our results demonstrate that PKC activation is one major pathway through which T-cells become activated.
Assuntos
Interleucina-2/biossíntese , Isoquinolinas/farmacologia , Piperazinas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Receptores de Interleucina-2/biossíntese , Sulfonamidas , Linfócitos T/fisiologia , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina , Divisão Celular/efeitos dos fármacos , Humanos , Técnicas In Vitro , Interleucina-4/fisiologia , Ativação Linfocitária/efeitos dos fármacos , Fito-Hemaglutininas/farmacologia , RNA Mensageiro/biossíntese , Linfócitos T/efeitos dos fármacos , Timidina/metabolismo , TrítioRESUMO
1-(5-Isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7), a potent and selective inhibitor of protein kinase C (PKC), inhibited PHA-stimulated bovine peripheral blood mononuclear cell (PBMC) proliferation, interleukin-2 (IL-2) production, and cytosolic PKC activity without affecting the cell viabilities. Presence of exogenous cytokines, such as purified human IL-2 or recombinant bovine IL-2 (rbovIL-2), reversed the H-7 inhibitory effects on PHA-stimulated PBMC proliferation. We conclude that the PKC enzyme plays an important role as a second messenger in bovine PBMC proliferation in the early stages of cell activation.
Assuntos
Interleucina-2/biossíntese , Isoquinolinas/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Piperazinas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Sulfonamidas , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina , Análise de Variância , Animais , Bovinos , Divisão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citosol/enzimologia , Interleucina-2/farmacologia , Isoquinolinas/antagonistas & inibidores , Leucócitos Mononucleares/imunologia , Ativação Linfocitária , Fito-Hemaglutininas/imunologia , Piperazinas/antagonistas & inibidores , Proteínas RecombinantesRESUMO
Bovine viral diarrhea (BVD) virus inhibited phytohemagglutinin (PHA)-stimulated bovine peripheral blood mononuclear cell (PBMC) proliferation and bovine interleukin-2 (IL-2) production. In the controls, the heat-inactivated BVD virus was not capable of suppressing the PHA-stimulated PBMC proliferation. Presence of exogenous cytokines, such as purified human IL-2, recombinant bovine interleukin-1 (rbovIL-1), recombinant bovine IL-2, and recombinant human IL-6 failed to reverse the BVD virus-induced immunosuppression. Also, we found that the BVD virus inhibited PHA and IL-2 induced proliferation of bovine PBMC in the early and late stages of activation. In summary, our data suggest that BVD virus induced immunosuppression was not due to destruction of the PBMC but may be inhibiting one or more of the important intracellular enzymes that may regulate PBMC proliferation.
