Gonococci possessing only certain P.II outer membrane proteins interact with human neutrophils.

We investigated the role of the protein II (P.II) family of gonococcal outer membrane proteins in the interaction of seven single P.II variants of Neisseria gonorrhoeae FA1090 with human neutrophils in vitro. The abilities of nonpiliated gonococci to adhere to and be killed by neutrophils and to stimulate luminol-dependent chemiluminescence (CL) depended on the possession of at least one P.II. Gonococci lacking P.II (i.e., P.II-) adhered poorly to and were not killed by neutrophils and induced only minimal CL. Although most P.II-containing (i.e., P.II+) variants adhered to, stimulated, and were readily killed by neutrophils, one variant, containing P.IIa, possessed none of these characteristics; it acted just like a P.II- variant. No correlation was found between the colony opacity phenotype and the interaction of gonococci with neutrophils. Data from CL experiments suggest that the stimulatory effect of P.II was dominant over that of pili; i.e., piliated P.II+ gonococci were much more stimulatory than piliated P.II- gonococci. The results indicate that most but not all P.II proteins mediate, in part or in full, the interaction of N. gonorrhoeae with human neutrophils, including adherence, stimulation of the neutrophil respiratory burst, and phagocytic killing.