Functional requirement for SAP in 2B4-mediated activation of human natural killer cells as revealed by the X-linked lymphoproliferative syndrome.
X-linked lymphoproliferative syndrome (XLP) is an immunodeficiency characterized by life-threatening infectious mononucleosis and EBV-induced B cell lymphoma. The gene mutated in XLP encodes SLAM (signaling lymphocytic activation molecule-associated protein)-associated protein (SAP), a small SH2 domain-containing protein. SAP associates with 2B4 and SLAM, activating receptors expressed by NK and T cells, and prevents recruitment of SH2 domain-containing protein tyrosine phosphatase-2 SHP-2) to the cytoplasmic domains of these receptors. The phenotype of XLP may therefore result from perturbed signaling through SAP-associating receptors. We have addressed the functional consequence of SAP deficiency on 2B4-mediated NK cell activation. Ligating 2B4 on normal human NK cells with anti-2B4 mAb or interaction with transfectants bearing the 2B4 ligand CD48 induced NK cell cytotoxicity. In contrast, ligation of 2B4 on NK cells from a SAP-deficient XLP patient failed to initiate cytotoxicity. Despite this, CD2 or CD16-induced cytotoxicity of SAP-deficient NK cells was similar to that of normal NK cells. Thus, selective impairment of 2B4-mediated NK cell activation may contribute to the immunopathology of XLP.
Tangye
S G
SG
Centenary Institute for Cancer Medicine and Cell Biology, and University of Sydney, New South Wales, Australia. s.tangye@centenary.usyd.edu.au
Phillips
J H
JH
Lanier
L L
LL
Nichols
K E
KE
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D008040:Genetic Linkage; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics / Q000502:physiology*; D007153:Immunologic Deficiency Syndromes / Q000235:genetics / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins; D007694:Killer Cells, Natural / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D008232:Lymphoproliferative Disorders / Q000235:genetics / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D051379:Mice; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000502:physiology*; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D013577:Syndrome; D014407:Tumor Cells, Cultured; D014960:X Chromosome; D018909:src Homology Domains / Q000235:genetics / Q000276:immunology
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C084093:CD244 protein, human; D002352:Carrier Proteins; C490007:Cd244a protein, mouse; D006023:Glycoproteins; D007136:Immunoglobulins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C114953:SH2D1A protein, human; C499569:Sh2d1a protein, mouse; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1