title: Constitutively Opa-expressing and Opa-deficient neisseria gonorrhoeae strains differentially stimulate and survive exposure to human neutrophils.
abstract: The Neisseria gonorrhoeae (the gonococcus [Gc]) opacity-associated (Opa) proteins mediate bacterial binding and internalization by human epithelial cells and neutrophils (polymorphonuclear leukocytes [PMNs]). Investigating the contribution of Opa proteins to gonococcal pathogenesis is complicated by high-frequency phase variation of the opa genes. We therefore engineered a derivative of Gc strain FA1090 in which all opa genes were deleted in frame, termed Opaless. Opaless Gc remained uniformly Opa negative (Opa(-)), whereas cultures of predominantly Opa(-) parental Gc and an intermediate lacking the "translucent" subset of opa genes (ΔopaBEGK) stochastically gave rise to Opa-positive (Opa(+)) bacterial colonies. Loss of Opa expression did not affect Gc growth. Opaless Gc survived exposure to primary human PMNs and suppressed the PMN oxidative burst akin to parental, Opa(-) bacteria. Notably, unopsonized Opaless Gc was internalized by adherent, chemokine-primed, primary human PMNs, by an actin-dependent process. When a non-phase-variable, in-frame allele of FA1090 opaD was reintroduced into Opaless Gc, the bacteria induced the PMN oxidative burst, and OpaD(+) Gc survived less well after exposure to PMNs compared to Opa(-) bacteria. These derivatives provide a robust system for assessing the role of Opa proteins in Gc biology.
authors.affiliation: Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health Sciences Center, Charlottesville, Virginia, USA.
authors.forename: Louise M
authors.initials: LM
authors.lastname: Ball
authors.forename: Alison K
authors.initials: AK
authors.lastname: Criss
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000276:immunology* / Q000378:metabolism*; D009504:Neutrophils / Q000276:immunology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; C090348:Opa protein, Neisseria