Biochemical nature and cellular distribution of the paired immunoglobulin-like receptors, PIR-A and PIR-B.
PIR-A and PIR-B, paired immunoglobulin-like receptors encoded, respectively, by multiple Pira genes and a single Pirb gene in mice, are relatives of the human natural killer (NK) and Fc receptors. Monoclonal and polyclonal antibodies produced against a recombinant PIR protein identified cell surface glycoproteins of approximately 85 and approximately 120 kD on B cells, granulocytes, and macrophages. A disulfide-linked homodimer associated with the cell surface PIR molecules was identified as the Fc receptor common gamma (FcRgammac) chain. Whereas PIR-B fibroblast transfectants expressed cell surface molecules of approximately 120 kD, PIR-A transfectants expressed the approximately 85-kD molecules exclusively intracellularly; PIR-A and FcRgammac cotransfectants expressed the PIR-A/ FcRgammac complex on their cell surface. Correspondingly, PIR-B was normally expressed on the cell surface of splenocytes from FcRgammac-/- mice whereas PIR-A was not. Cell surface levels of PIR molecules on myeloid and B lineage cells increased with cellular differentiation and activation. Dendritic cells, monocytes/macrophages, and mast cells expressed the PIR molecules in varying levels, but T cells and NK cells did not. These experiments define the coordinate cellular expression of PIR-B, an inhibitory receptor, and PIR-A, an activating receptor; demonstrate the requirement of FcRgammac chain association for cell surface PIR-A expression; and suggest that the level of FcRgammac chain expression could differentially affect the PIR-A/PIR-B equilibrium in different cell lineages.
Kubagawa
H
H
Division of Developmental and Clinical Immunology, University of Alabama at Birmingham, 35294, USA.
Chen
C C
CC
Ho
L H
LH
Shimada
T S
TS
Gartland
L
L
Mashburn
C
C
Uehara
T
T
Ravetch
J V
JV
Cooper
M D
MD
D000818:Animals; D000906:Antibodies / Q000276:immunology; D001483:Base Sequence; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology; D005434:Flow Cytometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology; D011971:Receptors, Immunologic / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D013154:Spleen / Q000276:immunology; D014162:Transfection / Q000235:genetics
D000906:Antibodies; C105948:Pira1 protein, mouse; C105949:Pirb protein, mouse; D011956:Receptors, Cell Surface; D011961:Receptors, Fc; D011971:Receptors, Immunologic; D011994:Recombinant Proteins