Gonococcal interactions with human polymorphonuclear leukocytes

Northwestern University At Chicago, Evanston IL

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Abstract

[unreadable] DESCRIPTION (provided by applicant): Acute gonorrheal infection, caused by Neisseria gonorrhoeae (Gc), is characterized by the recruitment of massive numbers of polymorphonuclear leukocytes (PMNs) to the urogenital tract. However, infection persists in the presence of PMNs, suggesting Gc have evolved ways to thwart PMN killing. Supporting these observations, I have shown that Gc can survive in the presence of PMNs and that the killing that does occur is non-oxidative. The goals of my research are to elucidate what allows some Gc to survive exposure to PMNs and to identify the PMN factors that kill the remaining Gc. In Aim 1 of the proposal, I will determine how the subcellular localization of Gc associated with PMNs affects bacterial survival, by quantifying the viability of Gc adherent to and internalized by PMNs and examining the colocalization of Gc with PMN granules, lysosomes, and neutrophil extracellular traps. In Aim 2, I will identify the bactericidal components of PMNs that are active against Gc by assaying Gc survival after exposure to individual PMN factors and to PMN granule fractions. In these studies I will compare wild-type Gc to two mutants that are more susceptible to PMN killing (ngo1686 and recN), which will provide explanations for how wild-type Gc survive exposure to PMNs and how the ngo1686 and recN gene products aid in Gc survival. I have been studying the interplay of mucosal pathogens with host cells for ten years, beginning with graduate studies and continuing as a postdoctoral fellow with Dr. H. Steven Seifert. During the fellowship period, my research focus has evolved from pilin antigenic variation, which aids Gc in evading the adaptive immune response, to how Gc avoid PMN clearance, a crucial yet poorly understood aspect of pathogenesis of Gc. My immediate career goal, to be completed in the mentored phase, is to complete initial studies of Gc-PMN interactions that will lay the foundation for obtaining an independent faculty position. This will support my long-term career goal, to direct a laboratory performing cutting-edge Gc pathogenesis research. RELEVANCE TO PUBLIC HEALTH: Gonorrhea is the second-most prevalent sexually transmitted disease in the US and worldwide. Infection causes reproductive tract scarring and sterility in both men and women and blindness in infants, and individuals with gonorrhea are more susceptible to HIV infection. Understanding how the host immune response is subverted during acute gonorrheal infection is a critical first step in finding new therapies for treatment of this disease. [unreadable] [unreadable] [unreadable]