Experimental Human Gonococcal Urethritis. 250 Neisseria gonorrhoeae MSllmkC areInfective

摘要

Netsseria gonorrhoeae MS11mkA (mkA) expresses one 3.6kDa lipooligosaccharide(LOS). Variant Ms11mkC (mkC), expressing four larger LOSs, occurs in vitro among mkA at a frequency of 1O-1; Infectivity of these variants was compared in 2 groups of volunteers inoculated with 40,000 piliated, Opagonococci of either strain. The mkC variant infected 5 of 5 while micA infected only 2 (40%) of 5. Gonococci recovered from the micA infections showed a transition toward the mkC LOS phenotype. The micA inoculum contained 40 mkC gonococci. These data confirmed earlier studies and suggested that small numbers of inkc gonococci would be infective. This hypothesis was tested in three more experiments. In two, volunteers were inoculated with 250 or 1250 mkC, infecting 3 of 7 in each group, and in the third, 1600 mkC infected 2 of 6, resulting in a total of 8 of 20 infected by =1600 mkC. Gonococci shed by infected volunteers maintained the mkC LOS phenotype but shifted from Opa to Opa+. Thus, LOS and opacity protm, as well as pilus, are gonococcal virulence factors.