Gonococcal infection in endotoxin-resistant and endotoxin-susceptible mice

The role of endotoxin responsiveness in defense against gonococcal infection was studied in endotoxin-resistant (C3H/HeJ) and endotoxin-susceptible (C3H/HeN) mice by using a model of disseminated gonococcal infection (DGI) and a model of gonococcal survival in the female genital tract to determine the ability of the mice to eliminate gonococci. The 50% lethal dose in the DGI model was 10(9.6) for C3H/HeJ mice and 10(5.2) for C3H/HeN mice. Levels of bacteremia during infection indicated the C3H/HeJ mice cleared large numbers of gonococci from their peripheral blood by 24 h post-inoculation but that C3H/HeN mice did not. Additionally, the peritoneal leukocyte response after intraperitoneal inoculation of gonococci was greater in C3H/HeJ mice than in C3H/HeN mice, which suggested that the ability to mount an inflammatory response to endotoxin may be important in defense against DGI. Besides being different in susceptibility to DGI, C3H/HeJ mice were found to be more resistant then C3H/HeN mice to genital colonization by gonococci. The resistance of C3H/HeJ mice to genital colonization by gonococci appeared to be due to both the high numbers of polymorphonuclear leukocytes in the genital secretion and the predominance of inhibitory gram-negative genital flora in that mouse strain.