Heterogeneity among Ly-49C natural killer (NK) cells: characterization of highly related receptors with differing functions and expression patterns.
Ly-49C is a member of the polymorphic family of murine NK cell inhibitory receptors. The 5E6 antibody that defines a subset of NK cells responsible for the rejection of parental H-2d bone marrow by F1 mice has been shown previously to react with Ly-49C. Here, the 5E6 antibody was found to detect two Ly-49C-related molecules in B6 mice. Two cDNA clones were isolated from B6 NK cells, one identical to previously reported Ly-49CB6 and the other a novel cDNA. The deduced amino acid sequence of the latter differs from that of Ly-49CBALB at only 4 residues, whereas the previously reported Ly-49CB6 differs at 22 residues. Flow cytometric analyses of COS cells transfected with the two cDNAs showed that the 5E6 antibody binds to both Ly-49 molecules, while another anti-Ly-49C antibody, 4LO3311, binds to the newly described Ly-49C but not the previously reported Ly-49CB6. Two-color flow cytometric analysis detected 5E6+4LO3311- as well as 5E6+4LO3311+ subsets of NK cells from B6, but not BALB/c, mice. The level of Ly-49C expression on B6 NK cells detected by the 4LO3311 antibody was substantially lower than that on BALB/c NK cells. Binding specificity of the novel Ly-49CB6 was indistinguishable from that of Ly-49CBALB, whereas no binding was detectable with previously reported Ly-49CB6. These results demonstrate that the newly described Ly-49CB6, not the previously reported Ly-49CB6, is the probable B6 allelic form of Ly-49C. The previously reported Ly-49CB6 must be encoded by a separate gene and should be renamed Ly-49I. The implication of these results with respect to the role of Ly-49C in hybrid resistance is discussed.
Brennan
J
J
Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
Lemieux
S
S
Freeman
J D
JD
Mager
D L
DL
Takei
F
F
D000595:Amino Acid Sequence; D000818:Animals; D000950:Antigens, Ly / Q000096:biosynthesis; D001483:Base Sequence; D019556:COS Cells; D002462:Cell Membrane / Q000276:immunology; D017931:DNA Primers; D005434:Flow Cytometry; D007694:Killer Cells, Natural / Q000276:immunology*; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000737:chemistry*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D055630:Receptors, NK Cell Lectin-Like; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014162:Transfection
D000950:Antigens, Ly; D017931:DNA Primers; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D055630:Receptors, NK Cell Lectin-Like; D011994:Recombinant Proteins