Defining the Involvement of p38α MAPK in the Production of Anti- and Proinflammatory Cytokines Using an SB 203580-resistant Form of the Kinase

Despite its lack of specificity, the inhibitor SB 203580 has been widely used to implicate p38 mitogen-activated protein kinase (MAPK) in the synthesis of many cytokines. Here we show unequivocally that the production of interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor α (TNFα) requires p38 MAPK activity by demonstrating that the inhibitory effects of SB 203580 were reversed by expression of an SB 203580-resistant form of p38α (SBR-p38α) that fails to bind to SB 203580. This strategy established the requirement for p38 activity for the lipopolysaccharide-stimulated production of IL-10, IL-1β, and IL-6 by the monocytic cell WEHI 274 and the production of IL-6 and TNFα stimulated by ligation of the Fc-γ receptor of the mast cell MC/9. Expression of SBR-p38α in primary macrophages abrogated the ability of SB 203580 to inhibit the lipopolysaccharide-stimulated production of TNFα but not of IL-10. Expression of SBR-p38α in primary T lymphocytes abrogated the ability of SB 203580 to inhibit the production of interferon-γ induced by co-ligation of CD3 and CD28 but not the production of interferon-γ or IL-10 induced by IL-12. These results suggest that the levels of p38 MAPK activity required for maximal cytokine production vary with different cytokines and stimuli. Despite its lack of specificity, the inhibitor SB 203580 has been widely used to implicate p38 mitogen-activated protein kinase (MAPK) in the synthesis of many cytokines. Here we show unequivocally that the production of interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor α (TNFα) requires p38 MAPK activity by demonstrating that the inhibitory effects of SB 203580 were reversed by expression of an SB 203580-resistant form of p38α (SBR-p38α) that fails to bind to SB 203580. This strategy established the requirement for p38 activity for the lipopolysaccharide-stimulated production of IL-10, IL-1β, and IL-6 by the monocytic cell WEHI 274 and the production of IL-6 and TNFα stimulated by ligation of the Fc-γ receptor of the mast cell MC/9. Expression of SBR-p38α in primary macrophages abrogated the ability of SB 203580 to inhibit the lipopolysaccharide-stimulated production of TNFα but not of IL-10. Expression of SBR-p38α in primary T lymphocytes abrogated the ability of SB 203580 to inhibit the production of interferon-γ induced by co-ligation of CD3 and CD28 but not the production of interferon-γ or IL-10 induced by IL-12. These results suggest that the levels of p38 MAPK activity required for maximal cytokine production vary with different cytokines and stimuli. The stress-activated kinases of the p38 mitogen-activated protein kinase (p38 MAPK) 1The abbreviations used are: MAPK, mitogen-activated protein kinase; SBR, SB 203580-resistant; MAPKAP, MAPK-activated protein; MK2, MAPKAP kinase 2; HSP, heat shock protein; IL, interleukin; LPS, lipopolysaccharide; BMMφ, bone marrow-derived macrophages; TNFα, tumor necrosis factor α; GFP, green fluorescent protein; IFN-γ, interferon-γ; WT, wild type; Fc-γ R, Fc-γ receptor; IRES, internal ribosomal entry site; Fc-ϵ R, Fc-ϵ receptor; mIL, murine IL; ELISA, enzyme-linked immunosorbent assay. 1The abbreviations used are: MAPK, mitogen-activated protein kinase; SBR, SB 203580-resistant; MAPKAP, MAPK-activated protein; MK2, MAPKAP kinase 2; HSP, heat shock protein; IL, interleukin; LPS, lipopolysaccharide; BMMφ, bone marrow-derived macrophages; TNFα, tumor necrosis factor α; GFP, green fluorescent protein; IFN-γ, interferon-γ; WT, wild type; Fc-γ R, Fc-γ receptor; IRES, internal ribosomal entry site; Fc-ϵ R, Fc-ϵ receptor; mIL, murine IL; ELISA, enzyme-linked immunosorbent assay. family are serine-threonine kinases that are activated by environmental stresses like heat, UV irradiation, or osmotic stress (1Lee J.C. Laydon J.T. McDonnell P.C. Gallagher T.F. Kumar S. Green D. McNulty D. Blumenthal M.J. Heys J.R. Landvatter S.W. et al.Nature. 1994; 372: 739-746Crossref PubMed Scopus (3107) Google Scholar, 2Han J. Lee J.D. Bibbs L. Ulevitch R.J. Science. 1994; 265: 808-811Crossref PubMed Scopus (2385) Google Scholar). In higher vertebrates, there are four related genes encoding p38α, p38β, p38γ, and p38δ (3Enslen H. Raingeaud J. Davis R.J. J. Biol. Chem. 1998; 273: 1741-1748Abstract Full Text Full Text PDF PubMed Scopus (468) Google Scholar, 4Stein B. Yang M.X. Young D.B. Janknecht R. Hunter T. Murray B.W. Barbosa M.S. J. Biol. Chem. 1997; 272: 19509-19517Abstract Full Text Full Text PDF PubMed Scopus (152) Google Scholar, 5Li Z. Jiang Y. Ulevitch R.J. Han J. Biochem. Biophys. Res. Commun. 1996; 228: 334-340Crossref PubMed Scopus (350) Google Scholar, 6Mertens S. Craxton M. Goedert M. FEBS Lett. 1996; 383: 273-276Crossref PubMed Scopus (133) Google Scholar, 7Lechner C. Zahalka M.A. Giot J.F. Moller N.P. Ullrich A. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 4355-4359Crossref PubMed Scopus (273) Google Scholar, 8Wang X.S. Diener K. Manthey C.L. Wang S. Rosenzweig B. Bray J. Delaney J. Cole C.N. Chan-Hui P.Y. Mantlo N. Lichenstein H.S. Zukowski M. Yao Z. J. Biol. Chem. 1997; 272: 23668-23674Abstract Full Text Full Text PDF PubMed Scopus (294) Google Scholar, 9Kumar S. McDonnell P.C. Gum R.J. Hand A.T. Lee J.C. Young P.R. Biochem. Biophys. Res. Commun. 1997; 235: 533-538Crossref PubMed Scopus (446) Google Scholar, 10Goedert M. Cuenda A. Craxton M. Jakes R. Cohen P. EMBO J. 1997; 16: 3563-3571Crossref PubMed Scopus (353) Google Scholar, 11Jiang Y. Gram H. Zhao M. New L. Gu J. Feng L. Di Padova F. Ulevitch R.J. Han J. J. Biol. Chem. 1997; 272: 30122-30128Abstract Full Text Full Text PDF PubMed Scopus (430) Google Scholar). The p38 MAPK proteins exhibit a high degree of structural and functional evolutionary conservation (1Lee J.C. Laydon J.T. McDonnell P.C. Gallagher T.F. Kumar S. Green D. McNulty D. Blumenthal M.J. Heys J.R. Landvatter S.W. et al.Nature. 1994; 372: 739-746Crossref PubMed Scopus (3107) Google Scholar, 2Han J. Lee J.D. Bibbs L. Ulevitch R.J. Science. 1994; 265: 808-811Crossref PubMed Scopus (2385) Google Scholar): the yeast ortholog, Hog1, is also activated in response to osmotic stress, and expression of the human protein in yeast lacking Hog1 restores their ability to grow in high osmolarity media (12Kumar S. McLaughlin M.M. McDonnell P.C. Lee J.C. Livi G.P. Young P.R. J. Biol. Chem. 1995; 270: 29043-29046Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar). Activation of p38 MAPK is triggered not only by physical stresses but also by the products of microorganisms such as endotoxin (1Lee J.C. Laydon J.T. McDonnell P.C. Gallagher T.F. Kumar S. Green D. McNulty D. Blumenthal M.J. Heys J.R. Landvatter S.W. et al.Nature. 1994; 372: 739-746Crossref PubMed Scopus (3107) Google Scholar, 2Han J. Lee J.D. Bibbs L. Ulevitch R.J. Science. 1994; 265: 808-811Crossref PubMed Scopus (2385) Google Scholar) and by proinflammatory cytokines such as IL-1 or TNFα (13Raingeaud J. Gupta S. Rogers J.S. Dickens M. Han J. Ulevitch R.J. Davis R.J. J. Biol. Chem. 1995; 270: 7420-7426Abstract Full Text Full Text PDF PubMed Scopus (2025) Google Scholar, 14Winston B.W. Chan E.D. Johnson G.L. Riches D.W.H. J. Immunol. 1997; 159: 4491-4497PubMed Google Scholar) indicating that p38 MAPK has multiple roles in innate immune responses. One of the groups that discovered mammalian p38 MAPK identified it through its ability to bind to a family of pyridinyl imidazole inhibitors (exemplified by the compound SB 203580), which were shown to inhibit the release of IL-1 or TNFα from endotoxin-stimulated monocytes (1Lee J.C. Laydon J.T. McDonnell P.C. Gallagher T.F. Kumar S. Green D. McNulty D. Blumenthal M.J. Heys J.R. Landvatter S.W. et al.Nature. 1994; 372: 739-746Crossref PubMed Scopus (3107) Google Scholar). Subsequently it has been shown that, of the four isoforms of p38 MAPK, only p38α and p38β are inhibited by SB 203580 (1Lee J.C. Laydon J.T. McDonnell P.C. Gallagher T.F. Kumar S. Green D. McNulty D. Blumenthal M.J. Heys J.R. Landvatter S.W. et al.Nature. 1994; 372: 739-746Crossref PubMed Scopus (3107) Google Scholar, 4Stein B. Yang M.X. Young D.B. Janknecht R. Hunter T. Murray B.W. Barbosa M.S. J. Biol. Chem. 1997; 272: 19509-19517Abstract Full Text Full Text PDF PubMed Scopus (152) Google Scholar, 8Wang X.S. Diener K. Manthey C.L. Wang S. Rosenzweig B. Bray J. Delaney J. Cole C.N. Chan-Hui P.Y. Mantlo N. Lichenstein H.S. Zukowski M. Yao Z. J. Biol. Chem. 1997; 272: 23668-23674Abstract Full Text Full Text PDF PubMed Scopus (294) Google Scholar, 9Kumar S. McDonnell P.C. Gum R.J. Hand A.T. Lee J.C. Young P.R. Biochem. Biophys. Res. Commun. 1997; 235: 533-538Crossref PubMed Scopus (446) Google Scholar, 10Goedert M. Cuenda A. Craxton M. Jakes R. Cohen P. EMBO J. 1997; 16: 3563-3571Crossref PubMed Scopus (353) Google Scholar, 15Cuenda A. Rouse J. Doza Y.N. Meier R. Cohen P. Gallagher T.F. Young P.R. Lee J.C. FEBS Lett. 1995; 364: 229-233Crossref PubMed Scopus (1970) Google Scholar, 16Young P.R. McLaughlin M.M. Kumar S. Kassis S. Doyle M.L. McNulty D. Gallagher T.F. Fisher S. McDonnell P.C. Carr S.A. Huddleston M.J. Seibel G. Porter T.G. Livi G.P. Adams J.L. Lee J.C. J. Biol. Chem. 1997; 272: 12116-12121Abstract Full Text Full Text PDF PubMed Scopus (534) Google Scholar, 17Cuenda A. Cohen P. Buee-Scherrer V. Goedert M. EMBO J. 1997; 16: 295-305Crossref PubMed Scopus (312) Google Scholar). We shown that p38 MAPK is also in Lee J.C. Young P.R. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar) by demonstrating its with a protein we shown to in response to the such as and factor M.J. J. Immunol. Google Scholar). is also that p38 MAPK has multiple roles in immune in that it is activated by ligation of and Young P.R. J. Immunol. 1997; 159: Google the of T or lymphocytes Young P.R. J. Immunol. 1997; 159: Google Scholar, J. J. Immunol. Google Scholar, J.D. Craxton A. J. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: PubMed Scopus Google Scholar, J. M.J. J. Immunol. Google and the receptor for the of Lee J.C. Young P.R. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar, T. H. N. K. P. Johnson G.L. J. Immunol. 1998; Google Scholar). The functional of of p38 MAPK are and are of the p38α is to the production of in response to with K. T. U. Johnson R. M. Full Text Full Text PDF PubMed Scopus Google Scholar). of the of p38 MAPK is the of inhibitors and the expression of of p38 MAPK or of its These roles for p38 in the production of such as TNFα, IL-1 (1Lee J.C. Laydon J.T. McDonnell P.C. Gallagher T.F. Kumar S. Green D. McNulty D. Blumenthal M.J. Heys J.R. Landvatter S.W. et al.Nature. 1994; 372: 739-746Crossref PubMed Scopus (3107) Google Scholar, Wang L. S.A. Davis J. Immunol. Google Scholar, Y. J. Immunol. Google IL-6 R. Cuenda A. S. Lee J.C. G. Cohen P. EMBO J. 1996; PubMed Scopus Google J. M.J. J. Immunol. Google Scholar, M. H. Raingeaud J. M. T. M.S. Davis R.J. EMBO J. 1998; PubMed Scopus Google Scholar, H.S. J. Immunol. PubMed Scopus Google H.S. J. Immunol. PubMed Scopus Google Scholar, H.S. M.M. J. Immunol. Google the factor IL-10 H.S. J. Immunol. PubMed Scopus Google Scholar, M. J. Immunol. 1998; Google Scholar, S. M.J. Immunol. PubMed Scopus Google as as a in PubMed Google Scholar) and T. T. Y. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). The of the of inhibitors or is in that in it is to unequivocally that the effects are by of p38 MAPK activity by with The compound SB 203580 has been used in to the roles of p38 MAPK in a of and The of the compound for p38 MAPK has been by Cuenda and A. Rouse J. Doza Y.N. Meier R. Cohen P. Gallagher T.F. Young P.R. Lee J.C. FEBS Lett. 1995; 364: 229-233Crossref PubMed Scopus (1970) Google Scholar) that it to inhibit kinases it has an ability to inhibit and the receptor Yang M.S. Davis R.J. Biol. 1997; PubMed Scopus Google Scholar, A. FEBS Lett. 1998; PubMed Scopus Google Scholar, Craxton M. N. Cohen P. Goedert M. Chem. Biol. 1998; Full Text PDF PubMed Scopus Google Scholar). SB 203580 to inhibit the of kinase in R. D. J. Immunol. Google Scholar) and induced a in of in Goedert M. P. Cohen P. PubMed Scopus Google Scholar). et J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) that SB 203580 protein kinase a that only higher that required to inhibit p38 MAPK the that a compound the of which not and were shown to inhibited by SB 203580 S. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar). of inhibitors of p38 MAPK for their proteins and their is not not in the a of proteins were it a we of their and Here we used a different strategy to effects of SB 203580 that were to of p38 This a of SB 203580 by the expression of an SB 203580-resistant form of p38α (SBR-p38α) that fails to bind to SB 203580 but in its and activity R.J. McLaughlin M.M. Kumar S. Wang Z. M.J. Lee J.C. Adams J.L. Livi G.P. Young P.R. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar). SB 203580 to the of the kinase P.R. McLaughlin M.M. Kumar S. Kassis S. Doyle M.L. McNulty D. Gallagher T.F. Fisher S. McDonnell P.C. Carr S.A. Huddleston M.J. Seibel G. Porter T.G. Livi G.P. Adams J.L. Lee J.C. J. Biol. Chem. 1997; 272: 12116-12121Abstract Full Text Full Text PDF PubMed Scopus (534) Google and and the been shown to for SB 203580 of with and is to the ability of p38α to bind SB its to by SB 203580 R.J. McLaughlin M.M. Kumar S. Wang Z. M.J. Lee J.C. Adams J.L. Livi G.P. Young P.R. J. Biol. Chem. 1998; 273: Full Text Full Text PDF PubMed Scopus Google Scholar). The that expression of SBR-p38α a are with SB 203580 that the to of p38 MAPK In cell such as which only p38α and not the SB p38β D. M. Manthey C.L. J. Immunol. Google it also that the activity in the that of Expression of an SB 203580-resistant of p38 MAPK used to that the inhibitory of SB 203580 of MAPKAP and and stress-activated protein of p38 MAPK but that the ability of SB 203580 to not P. Goedert M. Cohen P. FEBS Lett. PubMed Scopus Google Scholar). We SBR-p38α in cell monocytic or mast and in of primary macrophages and T demonstrating that a monocytic cell that SBR-p38α to the inhibitory of SB 203580 the production of IL-10, IL-1β, and IL-6, we p38α in the production of cytokines. the inhibitory effects of SB 203580 the production of IL-6 and TNFα in mast cell stimulated by ligation of the Fc-γ receptor were abrogated by expression of Expression of SBR-p38α in primary bone marrow-derived macrophages abrogated the ability of SB 203580 to inhibit the production of TNFα, not the production of IL-10. Expression of SBR-p38α in primary T lymphocytes abrogated the ability of SB 203580 to inhibit the production of that induced by co-ligation of the T cell receptor and CD28 but not that induced by IL-12. These results the of p38α in the production of IL-1β, IL-6, IL-10, TNFα, and the in the of expression of SBR-p38α in the inhibitory of SB 203580 the production of the cytokine in response to different that different levels of p38α activity were required for to different stimuli. there were that different levels of p38α activity were required for the production of the cytokine by different and monocytic WEHI and mast cell were in in with and as a of from were stimulated with in for and the T were by in as a of H. F. J. Immunol. PubMed Scopus Google Scholar). The and from the were and with of primary bone marrow-derived to as BMMφ, bone were in with as a of a human cell were in with and encoding wild p38α or the p38α that were by were the expression which an ribosomal entry expression and a were as by the were and of cell were with with to for of primary bone were from and and for in a of as a of cell and were with with for The with with the cytokines. bone high levels of were by cell a and in to of primary T that been stimulated with for were with for in with and of T high levels of were by cell and used used used the and used and were used were with or SB 203580 in for The were and a as H.S. J. Immunol. PubMed Scopus Google Scholar). murine IL-1β, IL-10, and TNFα from were used as and were in as and the of proteins in the by protein of protein were to and MAPKAP kinase kinase activity an in kinase with as a Lee J.C. Young P.R. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar). WEHI SBR-p38α to with in SB 203580-resistant p38 MAPK that, in the in which and been to and that the in p38 MAPK activity were to by SB 203580. SBR-p38α or were in a monocytic cell WEHI high levels of wild or p38α were identified by with MAPK shown in the levels of SBR-p38α were the levels of p38 the of SBR-p38α and its to SB WEHI or SBR-p38α were stimulated with or to of p38 MAPK and its in the levels of of p38 MAPK in and its activity in an in kinase as the The degree of of the of of the in activity of p38α shown in the in in activity of p38 MAPK in that were and were stimulated with or were inhibited by SB 203580. In in SBR-p38α in levels of p38 MAPK activity were and were not to by SB 203580. Expression of SBR-p38α MAPK in a the of SB 203580 to the of IL-10, IL-1β, and IL-6 the of p38α MAPK in the production of WEHI or SBR-p38α MAPK were stimulated with were and the levels of cytokines were by SB 203580 inhibited IL-10 production by WEHI MAPK in a with and with an of In in SBR-p38α the production of IL-10 inhibited by SB 203580 the production of by inhibited by SB 203580 with SB 203580. in the ability of SB 203580 to inhibit the production of The production of IL-6 inhibited by SB SB 203580 inhibited the production of IL-6 by In SB 203580 inhibited IL-6 production These results that p38α MAPK an in the production of IL-10 and The that the production of IL-6 from WEHI inhibited by SB 203580 the production of IL-10 or that p38 MAPK activity for only a of IL-6 production or that the of activity that required for IL-10 or production and to or the activity in the of SB 203580 In the that expression of SBR-p38α abrogated the of IL-6 production by SB 203580 that the of SB and higher to of p38 MAPK Expression of SBR-p38α in the SB of the of IL-6 and TNFα by of Fc-γ the of p38 MAPK in the production of cytokines in cell in response to a different we or SBR-p38α in the mast cell MC/9. multiple cytokines in response to of Fc-ϵ and Fc-γ R. or SBR-p38α were stimulated with the We that of by a triggered the release of IL-6 and TNFα from SB 203580 inhibited the production of IL-6 by not and by by The production of TNFα also inhibited but to a the with the monocytic cell WEHI expression of SBR-p38α in in the of the inhibitory of SB 203580 the production of IL-6 and TNFα a and These that the production of IL-6 and TNFα by mast stimulated by ligation of the Fc-γ in the activity of p38α Expression of SBR-p38α in the of SB 203580 to the of we the effects of SB 203580 the production of cytokines from primary We used to or SBR-p38α in bone which we induced to that the levels of or SBR-p38α in were in the of cell and from to of the levels of p38 MAPK not We that SB 203580 inhibited the production of TNFα by of MAPK with an of with SB 203580 levels of TNFα by IL-10 production to by SB 203580 with an of not Expression of SBR-p38α in of abrogated the inhibitory of SB 203580 the production of in SB 203580 the of TNFα production that in that were with the for of SB 203580 by the that the production of IL-10 by macrophages SBR-p38α to inhibited by SB 203580 the of TNFα production by SB 203580 in SBR-p38α to from of the inhibitory of SB 203580 TNFα but not of its TNFα by of IL-10 This is with that IL-10 production to by SB TNFα Expression of SBR-p38α the of by SB 203580 from with are a of an of the and the is also the of a which with but has as B. R. B. J.C. Y. B. F. N. Wang J. K. F. T. M. D. J. S. Y. J.S. D. R. C. J.F. Full Text Full Text PDF PubMed Scopus Google Scholar). We that SB 203580 the production of from macrophages through a that, in of the production of IL-10 and of its inhibitory production H.S. J. Immunol. PubMed Scopus Google Scholar). the of p38α MAPK in or SBR-p38α MAPK were stimulated with LPS, and with shown in SB 203580 production from or the expression of SBR-p38α to the ability of SB 203580 to the production of as shown in it the ability of SB 203580 to inhibit TNFα production by the in that the expression of SBR-p38α to the ability of SB 203580 to inhibit the production of IL-10 in results are with that the ability of SB 203580 to production to its ability to inhibit IL-10 production H.S. J. Immunol. PubMed Scopus Google Scholar). Expression of SBR-p38α in T SB of and IL-10 the the effects of expression of SBR-p38α the of SB 203580 cytokine production in primary T T lymphocytes were activated with and were with encoding or SBR-p38α and the of an high levels of GFP, and high levels of or were cell The T lymphocytes were by with for CD3 and CD28 in the or of SB 203580 shown in a and SB 203580 inhibited the production of and IL-10 by T cell not In T SBR-p38α were to the effects of SB 203580 the production of stimulated by ligation of CD3 and CD28 the inhibitory of SB 203580 the production of stimulated by co-ligation of CD3 and CD28 from of In the expression of SBR-p38α only a of the SB of IL-10 production by the We also the response of the of to a different which in the of induced activated T lymphocytes to and IL-10. We that SB 203580 inhibited the production of and IL-10. in with the production stimulated by co-ligation of CD3 and the expression of SBR-p38α to the SB of the production of induced by and The expression of SBR-p38α only the inhibitory of SB 203580 the IL-10 production the results cell were stimulated by co-ligation of CD3 and the of T lymphocytes SBR-p38α were to the SB of the production of in response to ligation of CD3 and CD28 but were only to the SB of the production of in response to and We as a requirement for higher levels of p38 activity for production of in response to and the widely used p38 MAPK inhibitor SB 203580 also The of the of inhibitors and the of p38α it to unequivocally to Here we the ability of expression of an SB 203580-resistant form of p38α to effects of SB 203580 that are to of p38α to its in the production of and cytokines. These roles for p38α in the production of IL-1β, IL-6, IFN-γ, TNFα, and IL-10 in cell and of primary an the of a response to by SB 203580 and the of expression of SBR-p38α required to of that response by SB 203580. This that there are in the of p38α activity required for the production of different cytokines as as of the cytokine in response to different stimuli. In the monocytic cell WEHI the production of IL-10 and to by SB 203580 and the inhibitory of SB 203580 abrogated by expression of The production of IL-6 from WEHI only inhibited by SB but abrogated by expression of results were in the mast cell the production of IL-6 and TNFα in response to ligation of the Fc-γ receptor and the inhibitory of SB 203580 abrogated by expression of These that the inhibitory of SB 203580 the production of IL-1β, IL-6, IL-10, and TNFα to of primary bone marrow-derived macrophages were the results were but we that, in to the results with WEHI high levels of expression of SBR-p38α in of to the inhibitory of SB 203580 IL-10 We the that the production of IL-10 by to by SB 203580 which is with results in human monocytes or murine macrophages H.S. J. Immunol. PubMed Scopus Google Scholar, M. J. Immunol. 1998; Google Scholar). This with that for of the production of cytokines the that the production of IL-10 requires higher levels of p38α The that expression of SBR-p38α in the monocytic cell WEHI higher levels in the primary the inhibitory of SB 203580 IL-10 production is with is that p38 MAPK not for IL-10 synthesis in and that SB 203580 IL-10 production through of that the of SB 203580 for of to as as that for of IL-10 production in WEHI 274 monocytes p38α shown to the We that SB 203580 the production of by macrophages through a that of IL-10 production H.S. J. Immunol. PubMed Scopus Google Scholar) and of p38 such as synthesis Z. J. Biol. Chem. 1997; 272: Full Text Full Text PDF PubMed Scopus Google Scholar). that of SBR-p38α not to to the inhibitory of SB 203580 IL-10 it is not that of SBR-p38α not the of SB 203580 production that of SBR-p38α abrogated the inhibitory of SB 203580 TNFα production a for p38α in TNFα is with the of et A. A. C. R. C. M. Biol. PubMed Scopus Google Scholar) that the of MK2, which is and activated by p38 MAPK, results in a in TNFα that in primary macrophages SBR-p38α MAPK TNFα production inhibited by SB 203580 but the that in SB 203580 inhibited the production of IL-10 and its inhibitory TNFα In that the inhibitory of SB 203580 TNFα, IL-6, IL-10 production in WEHI 274 or primary macrophages reversed by expression of SB 203580-resistant p38α MAPK activity and the that only of the SB p38 MAPK p38α MAPK D. M. Manthey C.L. J. Immunol. Google results that the inhibitory of SB 203580 the production of TNFα, IL-6, IL-1β, and IL-10 in macrophages the of p38α has been shown that p38α are activated by of T cell receptor or CD28 or by Young P.R. J. Immunol. 1997; 159: Google Scholar, J. J. Immunol. Google Scholar, J. M.J. J. Immunol. Google Scholar). The production of and IL-10 from T stimulated through T cell receptor and CD28 shown to inhibited by SB 203580 J. M.J. J. Immunol. Google Scholar, M. H. Raingeaud J. M. T. M.S. Davis R.J. EMBO J. 1998; PubMed Scopus Google Scholar, H.S. J. Immunol. PubMed Scopus Google Scholar, S. M.J. Immunol. PubMed Scopus Google Scholar). et S. J. Immunol. PubMed Scopus Google Scholar) that p38 MAPK activated by and required for In with we that SB 203580 inhibited the production of IL-10 and from T lymphocytes stimulated by co-ligation of CD3 and CD28 or by The expression of SBR-p38α MAPK in T lymphocytes the production of stimulated by co-ligation of CD3 and but it only the production of in response to and These that the through which co-ligation of CD3 and CD28 and of the receptor for production and different levels of p38 MAPK activity for maximal the the expression of SBR-p38α in primary T lymphocytes only a the of IL-10 production induced by ligation of CD3 and CD28 or IL-12. in the levels of p38 MAPK activity required for IL-10 production in response to stimuli. We for and the SB 203580-resistant F. Lee for J. for cell and G. and C. for