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Several carcinoembryonic antigens (CD66) serve as receptors for gonococcal opacity proteins.

Chen T, Grunert F, Medina-Marino A, Gotschlich EC - J. Exp. Med. (1997)

Bottom Line: This conclusion was based on the following observations.We also compared the adherence and invasion by Opa+ bacteria of CD66 transfected HeLa cells: HeLa-BGPa, HeLa-CGM6, HeLa-NCA, HeLa-CGM1a, HeLa-CEA, and HeLa-Neo serving as negative control.Among the Opa proteins tested, OpaC proved to be bifunctional, able to mediate adherence to both syndecan receptors and to CD66 antigens.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY 10021-6399, USA.

ABSTRACT
Neisseria gonorrhoeae (GC) is a human pathogen that adheres to and invades genital surfaces. Although pili are required for the initial adherence, the interaction of GC with epithelial cells is also promoted by a family of outer membrane proteins, the opacity (Opa) proteins such as OpaA protein from strain MS11. Studies have demonstrated that the interaction of the OpaA GC with epithelial cells involves binding to heparan sulfate attached to syndecan receptors. However, other Opa proteins interact with CEA gene family member 1 (CGM1) or biliary glycoprotein (BGP), members of the CD66 antigen family. In this study, we demonstrate that, in addition, the 180-kD carcinoembryonic antigen (CEA) is a receptor for Opa proteins. This conclusion was based on the following observations. First, transfected HeLa cells expressing CEA (HeLa-CEA) and the CEA-expressing colon cancer cell line (LS 174T) bound and subsequently engulfed the Opa+ bacteria. These interactions were inhibited by anti-CEA antibody, but could not be inhibited by addition of heparin. Furthermore, OpaI E. coli directly bound purified CEA. We also compared the adherence and invasion by Opa+ bacteria of CD66 transfected HeLa cells: HeLa-BGPa, HeLa-CGM6, HeLa-NCA, HeLa-CGM1a, HeLa-CEA, and HeLa-Neo serving as negative control. Using OpaI as the prototype, the relative ability of the transfected HeLa cell lines to support adherence was (CEA = BGPa >CGM1a >NCA >CGM6 = Neo). The ability to mediate invasion of the transfectant cells was (CGM1a >CEA >BGPa >NCA >CGM6 = Neo). Among the Opa proteins tested, OpaC proved to be bifunctional, able to mediate adherence to both syndecan receptors and to CD66 antigens.

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Binding specificity of  OpaC bacteria for both heparan  sulfate and CD66 receptors. OpaC  GC were incubated with wild-type  CHO-K1 cells and the isogenic  mutants 745 and 677 lacking surface heparan sulfate. OpaC GC adhered to CHO-K1 cells, but not  the 745 and 677 mutants (A). (B)  pGEM, pEXA, and pEXC were incubated with HeLa-CGM1a cells in  RPMI 1640 medium for 4.5 h. The  adherent and intracellular E. coli  were distinguished by incubation  with gentamicin. Only pEXC was  recovered in large numbers after  gentamicin treatment, although both  pEXA and pEXC adhered to the  HeLa-CGM1a.
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Figure 6: Binding specificity of OpaC bacteria for both heparan sulfate and CD66 receptors. OpaC GC were incubated with wild-type CHO-K1 cells and the isogenic mutants 745 and 677 lacking surface heparan sulfate. OpaC GC adhered to CHO-K1 cells, but not the 745 and 677 mutants (A). (B) pGEM, pEXA, and pEXC were incubated with HeLa-CGM1a cells in RPMI 1640 medium for 4.5 h. The adherent and intracellular E. coli were distinguished by incubation with gentamicin. Only pEXC was recovered in large numbers after gentamicin treatment, although both pEXA and pEXC adhered to the HeLa-CGM1a.

Mentions: Previously published studies demonstrated that OpaA-mediated adherence to Chang conjunctival and CHO cells is dependent on binding to heparan sulfate syndecan receptors (24, 25). These studies also showed that OpaC had this activity, and that OpaC GC were able to bind tritiated heparin. However, the data shown in Fig. 4, A and B indicated that pEXC was able to bind the HeLaCEA, and that this binding was inhibited by treatment with CD66 antibody, suggesting that OpaC was able to mediate both adherence to syndecans and CD66 antigens. To provide further evidence that OpaC-mediated adherence to CHO epithelial cells is heparan sulfate dependent, we examined the adherence to heparan sulfate-deficient CHO mutants 745 and 677. Compared to wild-type CHO-K1, OpaC GC adhered to mutant 745 and 677 at a very low level (Fig. 6 A). Further proof for reactivity with CD66 antigens is provided in Fig. 6 B showing that pEXC, but not pEXA, is internalized by HeLa-CGM1a.


Several carcinoembryonic antigens (CD66) serve as receptors for gonococcal opacity proteins.

Chen T, Grunert F, Medina-Marino A, Gotschlich EC - J. Exp. Med. (1997)

Binding specificity of  OpaC bacteria for both heparan  sulfate and CD66 receptors. OpaC  GC were incubated with wild-type  CHO-K1 cells and the isogenic  mutants 745 and 677 lacking surface heparan sulfate. OpaC GC adhered to CHO-K1 cells, but not  the 745 and 677 mutants (A). (B)  pGEM, pEXA, and pEXC were incubated with HeLa-CGM1a cells in  RPMI 1640 medium for 4.5 h. The  adherent and intracellular E. coli  were distinguished by incubation  with gentamicin. Only pEXC was  recovered in large numbers after  gentamicin treatment, although both  pEXA and pEXC adhered to the  HeLa-CGM1a.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196295&req=5

Figure 6: Binding specificity of OpaC bacteria for both heparan sulfate and CD66 receptors. OpaC GC were incubated with wild-type CHO-K1 cells and the isogenic mutants 745 and 677 lacking surface heparan sulfate. OpaC GC adhered to CHO-K1 cells, but not the 745 and 677 mutants (A). (B) pGEM, pEXA, and pEXC were incubated with HeLa-CGM1a cells in RPMI 1640 medium for 4.5 h. The adherent and intracellular E. coli were distinguished by incubation with gentamicin. Only pEXC was recovered in large numbers after gentamicin treatment, although both pEXA and pEXC adhered to the HeLa-CGM1a.
Mentions: Previously published studies demonstrated that OpaA-mediated adherence to Chang conjunctival and CHO cells is dependent on binding to heparan sulfate syndecan receptors (24, 25). These studies also showed that OpaC had this activity, and that OpaC GC were able to bind tritiated heparin. However, the data shown in Fig. 4, A and B indicated that pEXC was able to bind the HeLaCEA, and that this binding was inhibited by treatment with CD66 antibody, suggesting that OpaC was able to mediate both adherence to syndecans and CD66 antigens. To provide further evidence that OpaC-mediated adherence to CHO epithelial cells is heparan sulfate dependent, we examined the adherence to heparan sulfate-deficient CHO mutants 745 and 677. Compared to wild-type CHO-K1, OpaC GC adhered to mutant 745 and 677 at a very low level (Fig. 6 A). Further proof for reactivity with CD66 antigens is provided in Fig. 6 B showing that pEXC, but not pEXA, is internalized by HeLa-CGM1a.

Bottom Line: This conclusion was based on the following observations.We also compared the adherence and invasion by Opa+ bacteria of CD66 transfected HeLa cells: HeLa-BGPa, HeLa-CGM6, HeLa-NCA, HeLa-CGM1a, HeLa-CEA, and HeLa-Neo serving as negative control.Among the Opa proteins tested, OpaC proved to be bifunctional, able to mediate adherence to both syndecan receptors and to CD66 antigens.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY 10021-6399, USA.

ABSTRACT
Neisseria gonorrhoeae (GC) is a human pathogen that adheres to and invades genital surfaces. Although pili are required for the initial adherence, the interaction of GC with epithelial cells is also promoted by a family of outer membrane proteins, the opacity (Opa) proteins such as OpaA protein from strain MS11. Studies have demonstrated that the interaction of the OpaA GC with epithelial cells involves binding to heparan sulfate attached to syndecan receptors. However, other Opa proteins interact with CEA gene family member 1 (CGM1) or biliary glycoprotein (BGP), members of the CD66 antigen family. In this study, we demonstrate that, in addition, the 180-kD carcinoembryonic antigen (CEA) is a receptor for Opa proteins. This conclusion was based on the following observations. First, transfected HeLa cells expressing CEA (HeLa-CEA) and the CEA-expressing colon cancer cell line (LS 174T) bound and subsequently engulfed the Opa+ bacteria. These interactions were inhibited by anti-CEA antibody, but could not be inhibited by addition of heparin. Furthermore, OpaI E. coli directly bound purified CEA. We also compared the adherence and invasion by Opa+ bacteria of CD66 transfected HeLa cells: HeLa-BGPa, HeLa-CGM6, HeLa-NCA, HeLa-CGM1a, HeLa-CEA, and HeLa-Neo serving as negative control. Using OpaI as the prototype, the relative ability of the transfected HeLa cell lines to support adherence was (CEA = BGPa >CGM1a >NCA >CGM6 = Neo). The ability to mediate invasion of the transfectant cells was (CGM1a >CEA >BGPa >NCA >CGM6 = Neo). Among the Opa proteins tested, OpaC proved to be bifunctional, able to mediate adherence to both syndecan receptors and to CD66 antigens.

Show MeSH
Related in: MedlinePlus