Opsonophagocytosis of Neisseria gonorrhoeae: Interaction of Local and Disseminated Isolates with Complement and Neutrophils

The phagocytosis of serum-sensitive (SS) and serum-resistant (SR) gonococci by neutrophils was examined. SS strains were more rapidly and completely ingested and killed than were SR strains (8.8% + 3.4% vs. 64.4% a 7.7% survival at 30 min [P < .005]) in C8-deficient serum or C8-depleted normal serum. Opsonic requirements of the two types of isolates differed. Heat-labile and -stable serum factors played an important role in the phagocytosis of SS but not SR strains. Indeed, killing of SR strains by polymorphonuclear neutrophils did not vary over a 1,000-fold change in serum concentration. SS strains consumed and fixed C3 more rapidly and in greater amounts than did SR strains (83.3% a 17.4% vs. 20.8% + 5.0% at 10 min [P < .01]). However, this difference in C3 consumption and fixation did not completely account for the difference in phagocytosis because killing of SS strains was still greater than that of SR strains under conditions of equal C3 fixation.