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Heterogeneity among Ly-49C natural killer (NK) cells: characterization of highly related receptors with differing functions and expression patterns.

Brennan J, Lemieux S, Freeman JD, Mager DL, Takei F - J. Exp. Med. (1996)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.

ABSTRACT
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.

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Binding of Ly-49C to target cells. (A) COS cells were transfected with  vector alone (a, b), Ly-49CBALB (c, d), Ly-49CB6 (e, f    ), or Ly-49IB6 (g, h), and incubated with the murine lymphoid lines A20 (H-2d) (a, c, e, g) and IC-21 (H-2b) (b, d,  f, h). After a 2 h coincubation, unbound cells were washed away, and plates were  photographed. (B) The binding of IC-21 cells to COS cells transfected with Ly49CB6 was tested as above in the absence (a) or presence (b) of the 4LO3311 antibody. IC-21 binding to cells transfected with vector alone is shown in the absence (c)  or presence (d) of 4LO3311.
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Figure 4: Binding of Ly-49C to target cells. (A) COS cells were transfected with vector alone (a, b), Ly-49CBALB (c, d), Ly-49CB6 (e, f    ), or Ly-49IB6 (g, h), and incubated with the murine lymphoid lines A20 (H-2d) (a, c, e, g) and IC-21 (H-2b) (b, d, f, h). After a 2 h coincubation, unbound cells were washed away, and plates were photographed. (B) The binding of IC-21 cells to COS cells transfected with Ly49CB6 was tested as above in the absence (a) or presence (b) of the 4LO3311 antibody. IC-21 binding to cells transfected with vector alone is shown in the absence (c) or presence (d) of 4LO3311.

Mentions: 5E6+ NK cells have been thought to receive negative signals upon interactions of Ly-49C with H-2b and, under certain circumstances, H-2d antigens on target cells. After having shown that 5E6+ NK cells in B6 mice actually comprise two distinct NK cell subsets and that each of these express distinct but highly related receptors, we next investigated the class I MHC binding properties of each of these B6 receptors. It has been shown previously that Ly-49AB6 and Ly-49CBALB expressed on COS cells by cDNA transfection mediate cell–cell adhesion by binding to class I MHC antigens on various opposing cell lines (6). Ly-49AB6 has been shown to bind H-2d structures (but not H-2b), whereas Ly-49CBALB binds to both H-2d and H-2b. When this same assay was used to test the B6 Ly-49 receptors, Ly-49CB6 bound to both H-2d and H-2b, as was the case for the highly related Ly-49CBALB (Fig. 4 A). Interestingly, Ly-49IB6 did not show any class I binding ability in this assay system. The binding was almost completely inhibited by the 4LO3311 antibody (Fig. 4 B), further indicating that the cell adhesion in this system is mediated by Ly-49C.


Heterogeneity among Ly-49C natural killer (NK) cells: characterization of highly related receptors with differing functions and expression patterns.

Brennan J, Lemieux S, Freeman JD, Mager DL, Takei F - J. Exp. Med. (1996)

Binding of Ly-49C to target cells. (A) COS cells were transfected with  vector alone (a, b), Ly-49CBALB (c, d), Ly-49CB6 (e, f    ), or Ly-49IB6 (g, h), and incubated with the murine lymphoid lines A20 (H-2d) (a, c, e, g) and IC-21 (H-2b) (b, d,  f, h). After a 2 h coincubation, unbound cells were washed away, and plates were  photographed. (B) The binding of IC-21 cells to COS cells transfected with Ly49CB6 was tested as above in the absence (a) or presence (b) of the 4LO3311 antibody. IC-21 binding to cells transfected with vector alone is shown in the absence (c)  or presence (d) of 4LO3311.
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Related In: Results  -  Collection

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Figure 4: Binding of Ly-49C to target cells. (A) COS cells were transfected with vector alone (a, b), Ly-49CBALB (c, d), Ly-49CB6 (e, f    ), or Ly-49IB6 (g, h), and incubated with the murine lymphoid lines A20 (H-2d) (a, c, e, g) and IC-21 (H-2b) (b, d, f, h). After a 2 h coincubation, unbound cells were washed away, and plates were photographed. (B) The binding of IC-21 cells to COS cells transfected with Ly49CB6 was tested as above in the absence (a) or presence (b) of the 4LO3311 antibody. IC-21 binding to cells transfected with vector alone is shown in the absence (c) or presence (d) of 4LO3311.
Mentions: 5E6+ NK cells have been thought to receive negative signals upon interactions of Ly-49C with H-2b and, under certain circumstances, H-2d antigens on target cells. After having shown that 5E6+ NK cells in B6 mice actually comprise two distinct NK cell subsets and that each of these express distinct but highly related receptors, we next investigated the class I MHC binding properties of each of these B6 receptors. It has been shown previously that Ly-49AB6 and Ly-49CBALB expressed on COS cells by cDNA transfection mediate cell–cell adhesion by binding to class I MHC antigens on various opposing cell lines (6). Ly-49AB6 has been shown to bind H-2d structures (but not H-2b), whereas Ly-49CBALB binds to both H-2d and H-2b. When this same assay was used to test the B6 Ly-49 receptors, Ly-49CB6 bound to both H-2d and H-2b, as was the case for the highly related Ly-49CBALB (Fig. 4 A). Interestingly, Ly-49IB6 did not show any class I binding ability in this assay system. The binding was almost completely inhibited by the 4LO3311 antibody (Fig. 4 B), further indicating that the cell adhesion in this system is mediated by Ly-49C.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus