EFFECT OF OPA EXPRESSION ON TRANSMIGRATION OF NEISSERIA GONORRHOEAE ACROSS POLARIZED EPITHELIAL CELLS
Le Van, Luz Angela Adriana
Stein, Daniel C
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<italic>Neisseria gonorrhoeae</italic> (GC) is a solely human pathogen that causes gonorrhea. This study examines how Opas, which are surface factors expressed by GC that undergo antigenic and phase variation can affect transmigration across epithelium. Opas are encoded by 11 different genes. A gonococcal variant that lacked all <italic>opa</italic> genes was constructed to help elucidate the role of Opa in pathogenesis. This variant retained most physical characteristics of the parent strain including growth rate and LOS profile but proved to produce a different interaction with other GC by being unable to bind LOS of adjacent GC and form microcolonies. Lack of Opa expression increased the ability of GC to transmigrate across polarized colonic epithelial cells T84. When the <italic>opa</italic> deletion variant was not expressing pili, bacteria were observed entering and crossing the polarized epithelia as early as four hours after infection. GC were observed at the bottom of the polarized epithelial monolayer demonstrated by confocal microscopy. While GC transmigrate across the monolayer, they do not appear to disrupt the integrity of tight junction proteins. Transepithelial resistance did not show a significant change and there was no leakage of FITC or HRP. Inhibitors of acid sphingomyelin and F-actin did not cause a redistribution of ZO-1 and did not increase the transmigration of GC. Only in the presence of EGTA, a calcium chelator, were Opa-expressing GC observed crossing the monolayer through visible disruption of the tight junctions. Induction of TNF-α by T84 cells was increase when infected with GC but not the production of IL-8. This study indicates that the lack of expression of Opa and pili leads to an increase in invasion into subepithelial tissues.