Arthritis in rabbits induced by killed Neisseria gonorrhoeae and gonococcal lipopolysaccharide

Intraarticular injections of viable N, gonorrhoeae, killed N. gonorrhoeae or gonococcal lipopolysaccharide (LPS) in rabbits' knees caused an acute, polymorphonuclear synovitis with abscess formation 24-72 h after the injection. At 5-7 days, a mononuclear infiltration with synovial lining cell hyperplasia developed, which in some rabbits persisted for one month. Gonococcal LPS, in amounts of 5 micrograms or greater, always caused a marked synovitis indistinguishable from that produced by viable N. gonorrhoeae. Gonococcal outer membrane protein used as a control in these experiments caused no or minimal synovitis in concentrations 50-fold higher than those used in the LPS inoculation experiments. These studies should provide a model to investigate the role of LPS in the arthritis associated with gonococcal infection.