the mean number of bacteria per phagocyte increased from 9.7 to 17.3 ( mean difference 7.6 , p less than 0.001 ) when the meningococci were opsonized with convalescent sera compared to sera obtained during the acute illness , and from 8.0 to 15.4 ( mean difference 7.4 , p less than 0.001 ) when opsonized with sera from immunized versus pre-immunized volunteers .
C0004611
bacteria
C0027575
meningococci