[Bactericidal antibodies to meningococcal serogroups A, B and C in persons inoculated with a polycomponent...

Three groups consisting of 56, 55 and 57 subjects were immunized with polycomponent meningococcal vaccine incorporating microbial cell-wall substance in the polymeric form. The vaccine was introduced in doses of 0.25 ml, 0.5 ml and 1.0 ml, respectively, which corresponded to 100 microns, 200 microns and 400 microns of the dry substance of the vaccine. Each of 53 subjects in the control group received placebo (physiological saline) in a dose of 0.5 ml. Serum specimens were taken from all vaccinees prior to injection and on days 21-24. After the injection of the vaccine in a dose of 0.25 ml the arithmetical mean of the antimeningococcal titers increased approximately 70-fold to serogroup A, 20-fold to serogroup B and 120-fold to serogroup C, and after the injection of the vaccine in doses of 0.5 ml and 1.0 ml the titers increased 225-fold, 80-fold and 480-fold, respectively. The fact of the formation of bactericidal antibodies to serogroup B meningococci is particularly noteworthy.