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Negative signaling pathways of the killer cell inhibitory receptor and Fc gamma RIIb1 require distinct phosphatases.

Gupta N, Scharenberg AM, Burshtyn DN, Wagtmann N, Lioubin MN, Rohrschneider LR, Kinet JP, Long EO - J. Exp. Med. (1997)

Bottom Line: When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition.In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal.These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA.

ABSTRACT
Inhibition of natural killer (NK) cells by the killer cell inhibitory receptor (KIR) involves recruitment of the tyrosine phosphatase SHP-1 by KIR and is prevented by expression of a dominant negative SHP-1 mutant. Another inhibitory receptor, the low affinity Fc receptor for immunoglobulin G (IgG) (Fc gamma RIIb1), has been shown to bind SHP-1 when cocross-linked with the antigen receptor on B cells (BCR). However, coligation of Fc gamma RIIb1 with BCR and with Fc epsilon RI on mast cells leads to recruitment of the inositol 5' phosphatase SHIP and to inhibition of mast cells from SHP-1-deficient mice. In this study, we evaluated the ability of these two inhibitory receptors to block target cell lysis by NK cells, and the contribution of SHP-1 and SHIP to inhibition. Recombinant vaccinia viruses encoding chimeric receptors and dominant negative mutants of SHP-1 and SHIP were used for expression in mouse and human NK cells. When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition. A dominant negative mutant of SHP-1 reverted the inhibition mediated by the KIR cytoplasmic tail but not that mediated by Fc gamma RIIb1. In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal. These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

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The cytoplasmic tail of human FcγRIIb1 can deliver an inhibitory signal in mouse NK cells. (A) Surface expression of KIR-6, KIR-6/RIIb1, and KIR-6tr on cells infected with 5, 5, and 10 PFU/cell of the  indicated recombinant vaccinia viruses, respectively. (B) Specific lysis of  the B cell line .221 (open circles), and its HLA-Cw3 transfectant (closed circles) by uninfected mouse NK cells or those infected with Vac-6, Vac-6/ RIIb1 or Vac-6tr. ADCC was induced by precoating the targets with 0.1  μg/ml of anti-HLA-DR mAb L243 for 30 min on ice. Effectors and targets were plated at the indicated ratios.
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Figure 2: The cytoplasmic tail of human FcγRIIb1 can deliver an inhibitory signal in mouse NK cells. (A) Surface expression of KIR-6, KIR-6/RIIb1, and KIR-6tr on cells infected with 5, 5, and 10 PFU/cell of the indicated recombinant vaccinia viruses, respectively. (B) Specific lysis of the B cell line .221 (open circles), and its HLA-Cw3 transfectant (closed circles) by uninfected mouse NK cells or those infected with Vac-6, Vac-6/ RIIb1 or Vac-6tr. ADCC was induced by precoating the targets with 0.1 μg/ml of anti-HLA-DR mAb L243 for 30 min on ice. Effectors and targets were plated at the indicated ratios.

Mentions: Expression of KIR-6 on mouse NK cells inhibits the antibody-dependent cell-mediated cytotoxicity of HLA-Cw3 positive .221 targets (15). NK1.1+, TCR− NK cells, prepared from the spleens of C57Bl/6 mice were infected with Vac-6, Vac-6/RIIb1, and Vac-6tr and tested for their ability to lyse .221 and .221-Cw3 target cells. The infected cells expressed comparable levels of the three receptors (Fig. 2 A). NK cells expressing KIR-6/RIIb1 lysed .221 cells but had reduced cytotoxic activity against .221-Cw3 cells. Uninfected cells and those infected with Vac-6tr lysed both .221 and .221-Cw3 to the same extent (Fig. 2 B). Thus, the cytoplasmic tail of FcγRIIb1 can deliver a signal that inhibits the cytotoxic function of NK cells.


Negative signaling pathways of the killer cell inhibitory receptor and Fc gamma RIIb1 require distinct phosphatases.

Gupta N, Scharenberg AM, Burshtyn DN, Wagtmann N, Lioubin MN, Rohrschneider LR, Kinet JP, Long EO - J. Exp. Med. (1997)

The cytoplasmic tail of human FcγRIIb1 can deliver an inhibitory signal in mouse NK cells. (A) Surface expression of KIR-6, KIR-6/RIIb1, and KIR-6tr on cells infected with 5, 5, and 10 PFU/cell of the  indicated recombinant vaccinia viruses, respectively. (B) Specific lysis of  the B cell line .221 (open circles), and its HLA-Cw3 transfectant (closed circles) by uninfected mouse NK cells or those infected with Vac-6, Vac-6/ RIIb1 or Vac-6tr. ADCC was induced by precoating the targets with 0.1  μg/ml of anti-HLA-DR mAb L243 for 30 min on ice. Effectors and targets were plated at the indicated ratios.
© Copyright Policy
Related In: Results  -  Collection

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Figure 2: The cytoplasmic tail of human FcγRIIb1 can deliver an inhibitory signal in mouse NK cells. (A) Surface expression of KIR-6, KIR-6/RIIb1, and KIR-6tr on cells infected with 5, 5, and 10 PFU/cell of the indicated recombinant vaccinia viruses, respectively. (B) Specific lysis of the B cell line .221 (open circles), and its HLA-Cw3 transfectant (closed circles) by uninfected mouse NK cells or those infected with Vac-6, Vac-6/ RIIb1 or Vac-6tr. ADCC was induced by precoating the targets with 0.1 μg/ml of anti-HLA-DR mAb L243 for 30 min on ice. Effectors and targets were plated at the indicated ratios.
Mentions: Expression of KIR-6 on mouse NK cells inhibits the antibody-dependent cell-mediated cytotoxicity of HLA-Cw3 positive .221 targets (15). NK1.1+, TCR− NK cells, prepared from the spleens of C57Bl/6 mice were infected with Vac-6, Vac-6/RIIb1, and Vac-6tr and tested for their ability to lyse .221 and .221-Cw3 target cells. The infected cells expressed comparable levels of the three receptors (Fig. 2 A). NK cells expressing KIR-6/RIIb1 lysed .221 cells but had reduced cytotoxic activity against .221-Cw3 cells. Uninfected cells and those infected with Vac-6tr lysed both .221 and .221-Cw3 to the same extent (Fig. 2 B). Thus, the cytoplasmic tail of FcγRIIb1 can deliver a signal that inhibits the cytotoxic function of NK cells.

Bottom Line: When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition.In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal.These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA.

ABSTRACT
Inhibition of natural killer (NK) cells by the killer cell inhibitory receptor (KIR) involves recruitment of the tyrosine phosphatase SHP-1 by KIR and is prevented by expression of a dominant negative SHP-1 mutant. Another inhibitory receptor, the low affinity Fc receptor for immunoglobulin G (IgG) (Fc gamma RIIb1), has been shown to bind SHP-1 when cocross-linked with the antigen receptor on B cells (BCR). However, coligation of Fc gamma RIIb1 with BCR and with Fc epsilon RI on mast cells leads to recruitment of the inositol 5' phosphatase SHIP and to inhibition of mast cells from SHP-1-deficient mice. In this study, we evaluated the ability of these two inhibitory receptors to block target cell lysis by NK cells, and the contribution of SHP-1 and SHIP to inhibition. Recombinant vaccinia viruses encoding chimeric receptors and dominant negative mutants of SHP-1 and SHIP were used for expression in mouse and human NK cells. When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition. A dominant negative mutant of SHP-1 reverted the inhibition mediated by the KIR cytoplasmic tail but not that mediated by Fc gamma RIIb1. In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal. These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

Show MeSH
Related in: MedlinePlus