title: Opa proteins and CEACAMs: pathways of immune engagement for pathogenic Neisseria.
abstract: Neisseria meningitidis and Neisseria gonorrhoeae are globally important pathogens, which in part owe their success to their ability to successfully evade human immune responses over long periods. The phase-variable opacity-associated (Opa) adhesin proteins are a major surface component of these organisms, and are responsible for bacterial adherence and entry into host cells and interactions with the immune system. Most immune interactions are mediated via binding to members of the carcinoembryonic antigen cell adhesion molecule (CEACAM) family. These Opa variants are able to bind to different receptors of the CEACAM family on epithelial cells, neutrophils, and T and B lymphocytes, influencing the innate and adaptive immune responses. Increased epithelial cell adhesion creates the potential for prolonged infection, invasion and dissemination. Furthermore, Opa proteins may inhibit T-lymphocyte activation and proliferation, B-cell antibody production, and innate inflammatory responses by infected epithelia, in addition to conferring increased resistance to antibody-dependent, complement-mediated killing. While vaccines containing Opa proteins could induce adhesion-blocking and bactericidal antibodies, the consequence of CEACAM binding by a candidate Opa-containing vaccine requires further investigation. This review summarizes current knowledge of the immunological consequences of the interaction between meningococcal and gonococcal Opa proteins and human CEACAMs, considering the implications for pathogenesis and vaccine development.
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, UK. manish.sadarangani@paediatrics.ox.ac.uk
authors.forename: Manish
authors.initials: M
authors.lastname: Sadarangani
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
authors.forename: Scott D
authors.initials: SD
authors.lastname: Gray-Owen
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D002272:Carcinoembryonic Antigen / Q000276:immunology* / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008585:Meningitis, Meningococcal / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D009345:Neisseria meningitidis / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011485:Protein Binding
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002272:Carcinoembryonic Antigen; D015815:Cell Adhesion Molecules; C090348:Opa protein, Neisseria