TY - JOUR
T1 - Inhibition of IFN-γ-induced class II transactivator expression by a 19-kDa lipoprotein from Mycobacterium tuberculosis
T2 - A potential mechanism for immune evasion
AU - Pai, Rish K.
AU - Convery, Marilyn
AU - Hamilton, Thomas A.
AU - Henry Boom, W.
AU - Harding, Clifford V.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2003/7/1
Y1 - 2003/7/1
N2 - Mycobacterium tuberculosis (MTB) persists inside macrophages despite vigorous immune responses. MTB and MTB 19-kDa lipoprotein inhibit class II MHC (MHC-II) expression and Ag processing by a Toll-like receptor 2-dependent mechanism that is shown in this study to involve a defect in IFN-γ induction of class II transactivator (CIITA). Exposure of macrophages to MTB or MTB 19-kDa lipoprotein inhibited IFN-γ-induced MHC-II expression, but not IL-4-induced MHC-II expression, by preventing induction of mRNA for CIITA (total, type I, and type IV), IFN regulatory factor-1, and MHC-II. MTB 19-kDa lipoprotein induced mRNA for suppressor of cytokine signaling (SOCS)1 but did not inhibit IFN-γ-induced Stat1 phosphorylation. Furthermore, the lipoprotein inhibited MHC-II Ag processing in SOCS1-/- macrophages. MTB 19-kDa lipoprotein did not inhibit translocation of phosphorylated Stat1 to the nucleus or Statl binding to and transactivation of IFN-γ-sensitive promoter constructs. Thus, MTB 19-kDa lipoprotein inhibited IFN-γ signaling independent of SOCS1 and without interfering with the activation of Stat1. Inhi-bition of IFN-γ-induced CIITA by MTB 19-kDa lipoprotein may allow MTB to evade detection by CD4+ T cells.
AB - Mycobacterium tuberculosis (MTB) persists inside macrophages despite vigorous immune responses. MTB and MTB 19-kDa lipoprotein inhibit class II MHC (MHC-II) expression and Ag processing by a Toll-like receptor 2-dependent mechanism that is shown in this study to involve a defect in IFN-γ induction of class II transactivator (CIITA). Exposure of macrophages to MTB or MTB 19-kDa lipoprotein inhibited IFN-γ-induced MHC-II expression, but not IL-4-induced MHC-II expression, by preventing induction of mRNA for CIITA (total, type I, and type IV), IFN regulatory factor-1, and MHC-II. MTB 19-kDa lipoprotein induced mRNA for suppressor of cytokine signaling (SOCS)1 but did not inhibit IFN-γ-induced Stat1 phosphorylation. Furthermore, the lipoprotein inhibited MHC-II Ag processing in SOCS1-/- macrophages. MTB 19-kDa lipoprotein did not inhibit translocation of phosphorylated Stat1 to the nucleus or Statl binding to and transactivation of IFN-γ-sensitive promoter constructs. Thus, MTB 19-kDa lipoprotein inhibited IFN-γ signaling independent of SOCS1 and without interfering with the activation of Stat1. Inhi-bition of IFN-γ-induced CIITA by MTB 19-kDa lipoprotein may allow MTB to evade detection by CD4+ T cells.
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M3 - Article
C2 - 12816996
AN - SCOPUS:0037530648
SN - 0022-1767
VL - 171
SP - 175
EP - 184
JO - Journal of Immunology
JF - Journal of Immunology
IS - 1
ER -