TAILIEUCHUNG - Chapter 137. Gonococcal Infections (Part 2)

Opacity-Associated Protein Another gonococcal surface protein that is important in adherence to epithelial cells is opacity-associated protein (Opa, formerly called protein II). Opa contributes to intergonococcal adhesion, which is responsible for the opaque nature of gonococcal colonies on translucent agar and the organism's adherence to a variety of eukaryotic cells, including polymorphonuclear leukocytes (PMNs). Certain Opa variants promote invasion of epithelial cells, and this effect has been linked with the ability of Opa to bind vitronectin, glycosaminoglycans, and several members of the carcinoembryonic antigen–related cell adhesion molecule (CEACAM) receptor family. N. gonorrhoeae Opa proteins that bind CEACAM 1, which is. | Chapter 137. Gonococcal Infections Part 2 Opacity-Associated Protein Another gonococcal surface protein that is important in adherence to epithelial cells is opacity-associated protein Opa formerly called protein II . Opa contributes to intergonococcal adhesion which is responsible for the opaque nature of gonococcal colonies on translucent agar and the organism s adherence to a variety of eukaryotic cells including polymorphonuclear leukocytes PMNs . Certain Opa variants promote invasion of epithelial cells and this effect has been linked with the ability of Opa to bind vitronectin glycosaminoglycans and several members of the carcinoembryonic antigen-related cell adhesion molecule CEACAM receptor family. N. gonorrhoeae Opa proteins that bind CEACAM 1 which is expressed by primary CD4 T lymphocytes suppress the activation and proliferation of these lymphocytes. This phenomenon may serve to explain the transient decrease in CD4 T lymphocyte counts associated with gonococcal infection. Porin Porin previously designated protein I is the most abundant gonococcal surface protein accounting for 50 of the organism s total outer-membrane protein. Porin molecules exist as trimers that provide anion-transporting aqueous channels through the otherwise-hydrophobic outer membrane. Porin shows stable interstrain antigenic variation and forms the basis for gonococcal serotyping. Two main serotypes have been identified strains are often associated with disseminated gonococcal infection DGI while strains usually cause local genital infections only. DGI strains are generally resistant to the killing action of normal human serum and do not incite a significant local inflammatory response therefore they may not cause symptoms at genital sites. These characteristics may be related to the ability of strains to bind to complement-inhibitory molecules resulting in a diminished inflammatory response. Porin can translocate to the cytoplasmic membrane of host cells a

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