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Major histocompatibility complex class I molecules modulate activation threshold and early signaling of T cell antigen receptor-gamma/delta stimulated by nonpeptidic ligands.

Carena I, Shamshiev A, Donda A, Colonna M, Libero GD - J. Exp. Med. (1997)

Bottom Line: CD94-mediated inhibition is more effective at low than at high doses of TCR ligand, which may focus T cell responses towards antigen-presenting cells presenting high amounts of antigen.CD94 engagement has major effects on TCR signaling cascade.These events may cause abortion of proximal TCR-mediated signaling and set a higher TCR activation threshold.

View Article: PubMed Central - PubMed

Affiliation: Experimental Immunology, Department of Research, University Hospital, Basel, Switzerland.

ABSTRACT
Killer cell inhibitory receptors and CD94-NKG2-A/B heterodimers are major histocompatibility complex class I-specific inhibitory receptors expressed by natural killer cells, T cell antigen receptor (TCR)-gamma/delta cells, and a subset of TCR-alpha/beta cells. We studied the functional interaction between TCR-gamma/delta and CD94, this inhibitory receptor being expressed on the majority of gamma/delta T cells. When engaged by human histocompatibility leukocyte antigen class I molecules, CD94 downmodulates activation of human TCR-gamma/delta by phosphorylated ligands. CD94-mediated inhibition is more effective at low than at high doses of TCR ligand, which may focus T cell responses towards antigen-presenting cells presenting high amounts of antigen. CD94 engagement has major effects on TCR signaling cascade. It facilitates recruitment of SHP-1 phosphatase to TCR-CD3 complex and affects phosphorylation of Lck and ZAP-70 kinase, but not of CD3 zeta chain upon TCR triggering. These events may cause abortion of proximal TCR-mediated signaling and set a higher TCR activation threshold.

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TCR-γ/δ stimulation with IPP in the presence  of HLA class I+ APC recruits  increased amounts of SHP-1  phosphatase to CD94 and to  TCR–CD3 complex and causes  tyrosine hypophosphorylation.  (A) Western blot performed with  anti–SHP-1 Abs after immunoprecipitations carried out with  anti-CD94 (lanes 2 and 3) or an  isotype-matched irrelevant mAb  (lane 1) from γ/δ T cells stimulated with IPP in the presence of  Daudi (lanes 1 and 2) or Daudi-β2 APCs (lane 3). (B) Anti–SHP-1  Western blot after immunoprecipitation with anti-CD3 ζ chain  mAbs. (C) Protein tyrosine phosphorylation of total cell lysates is visualized by immunoblotting with antiphosphotyrosine 4G10 mAb. Cells were lysed with 1% digitonin (A and  B) or with 1% NP-40 (C). Molecular mass markers are indicated on the  right in kilodaltons. Arrows indicate SHP-1 in A and B, and two hypophosphorylated proteins migrating at ∼70 and 130 kD in C. H, Ig heavy  chain of immunoprecipitating Abs.
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Figure 4: TCR-γ/δ stimulation with IPP in the presence of HLA class I+ APC recruits increased amounts of SHP-1 phosphatase to CD94 and to TCR–CD3 complex and causes tyrosine hypophosphorylation. (A) Western blot performed with anti–SHP-1 Abs after immunoprecipitations carried out with anti-CD94 (lanes 2 and 3) or an isotype-matched irrelevant mAb (lane 1) from γ/δ T cells stimulated with IPP in the presence of Daudi (lanes 1 and 2) or Daudi-β2 APCs (lane 3). (B) Anti–SHP-1 Western blot after immunoprecipitation with anti-CD3 ζ chain mAbs. (C) Protein tyrosine phosphorylation of total cell lysates is visualized by immunoblotting with antiphosphotyrosine 4G10 mAb. Cells were lysed with 1% digitonin (A and B) or with 1% NP-40 (C). Molecular mass markers are indicated on the right in kilodaltons. Arrows indicate SHP-1 in A and B, and two hypophosphorylated proteins migrating at ∼70 and 130 kD in C. H, Ig heavy chain of immunoprecipitating Abs.

Mentions: The inhibitory activities of KIRs have been ascribed to membrane recruitment of phosphatases and subsequent dephosphorylation of Lck, ZAP-70, and phospholipase C-γ (28). We tested whether SHP-1 phosphatase, which has been coprecipitated with the NKG2-A/NKR-P1C chimeric receptor (29), associates with CD94 expressed by γ/δ T cells. Indeed, SHP-1 was associated with CD94 in γ/δ T cells stimulated with IPP and the amount of coprecipitated SHP-1 was increased in the presence of Daudi-β2 APCs (Fig. 4 A).


Major histocompatibility complex class I molecules modulate activation threshold and early signaling of T cell antigen receptor-gamma/delta stimulated by nonpeptidic ligands.

Carena I, Shamshiev A, Donda A, Colonna M, Libero GD - J. Exp. Med. (1997)

TCR-γ/δ stimulation with IPP in the presence  of HLA class I+ APC recruits  increased amounts of SHP-1  phosphatase to CD94 and to  TCR–CD3 complex and causes  tyrosine hypophosphorylation.  (A) Western blot performed with  anti–SHP-1 Abs after immunoprecipitations carried out with  anti-CD94 (lanes 2 and 3) or an  isotype-matched irrelevant mAb  (lane 1) from γ/δ T cells stimulated with IPP in the presence of  Daudi (lanes 1 and 2) or Daudi-β2 APCs (lane 3). (B) Anti–SHP-1  Western blot after immunoprecipitation with anti-CD3 ζ chain  mAbs. (C) Protein tyrosine phosphorylation of total cell lysates is visualized by immunoblotting with antiphosphotyrosine 4G10 mAb. Cells were lysed with 1% digitonin (A and  B) or with 1% NP-40 (C). Molecular mass markers are indicated on the  right in kilodaltons. Arrows indicate SHP-1 in A and B, and two hypophosphorylated proteins migrating at ∼70 and 130 kD in C. H, Ig heavy  chain of immunoprecipitating Abs.
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Related In: Results  -  Collection

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Figure 4: TCR-γ/δ stimulation with IPP in the presence of HLA class I+ APC recruits increased amounts of SHP-1 phosphatase to CD94 and to TCR–CD3 complex and causes tyrosine hypophosphorylation. (A) Western blot performed with anti–SHP-1 Abs after immunoprecipitations carried out with anti-CD94 (lanes 2 and 3) or an isotype-matched irrelevant mAb (lane 1) from γ/δ T cells stimulated with IPP in the presence of Daudi (lanes 1 and 2) or Daudi-β2 APCs (lane 3). (B) Anti–SHP-1 Western blot after immunoprecipitation with anti-CD3 ζ chain mAbs. (C) Protein tyrosine phosphorylation of total cell lysates is visualized by immunoblotting with antiphosphotyrosine 4G10 mAb. Cells were lysed with 1% digitonin (A and B) or with 1% NP-40 (C). Molecular mass markers are indicated on the right in kilodaltons. Arrows indicate SHP-1 in A and B, and two hypophosphorylated proteins migrating at ∼70 and 130 kD in C. H, Ig heavy chain of immunoprecipitating Abs.
Mentions: The inhibitory activities of KIRs have been ascribed to membrane recruitment of phosphatases and subsequent dephosphorylation of Lck, ZAP-70, and phospholipase C-γ (28). We tested whether SHP-1 phosphatase, which has been coprecipitated with the NKG2-A/NKR-P1C chimeric receptor (29), associates with CD94 expressed by γ/δ T cells. Indeed, SHP-1 was associated with CD94 in γ/δ T cells stimulated with IPP and the amount of coprecipitated SHP-1 was increased in the presence of Daudi-β2 APCs (Fig. 4 A).

Bottom Line: CD94-mediated inhibition is more effective at low than at high doses of TCR ligand, which may focus T cell responses towards antigen-presenting cells presenting high amounts of antigen.CD94 engagement has major effects on TCR signaling cascade.These events may cause abortion of proximal TCR-mediated signaling and set a higher TCR activation threshold.

View Article: PubMed Central - PubMed

Affiliation: Experimental Immunology, Department of Research, University Hospital, Basel, Switzerland.

ABSTRACT
Killer cell inhibitory receptors and CD94-NKG2-A/B heterodimers are major histocompatibility complex class I-specific inhibitory receptors expressed by natural killer cells, T cell antigen receptor (TCR)-gamma/delta cells, and a subset of TCR-alpha/beta cells. We studied the functional interaction between TCR-gamma/delta and CD94, this inhibitory receptor being expressed on the majority of gamma/delta T cells. When engaged by human histocompatibility leukocyte antigen class I molecules, CD94 downmodulates activation of human TCR-gamma/delta by phosphorylated ligands. CD94-mediated inhibition is more effective at low than at high doses of TCR ligand, which may focus T cell responses towards antigen-presenting cells presenting high amounts of antigen. CD94 engagement has major effects on TCR signaling cascade. It facilitates recruitment of SHP-1 phosphatase to TCR-CD3 complex and affects phosphorylation of Lck and ZAP-70 kinase, but not of CD3 zeta chain upon TCR triggering. These events may cause abortion of proximal TCR-mediated signaling and set a higher TCR activation threshold.

Show MeSH