FUNCTIONAL-PROPERTIES OF NONHUMAN PRIMATE ANTIBODY TO PORPHYROMONAS-GINGIVALIS

The nonhuman primate (NHP) serves as a useful model for examining the host-parasite interactions in Porphyromonas gingivalis-associated peri odontal disease. This study determined the influence of NHP sera on (i ) the direct killing of P. gingivalis, (ii) P, gingivalis-induced supe roxide anion (O-2(-)) release from human polymorphonuclear leukocytes (PMNs), and (iii) the ability of PMNs to bind and phagocytize P. gingi valis. Three types of NHP sera were utilized: (i) normal or baseline s era; (ii) sera obtained after ligature-induced periodontitis; and (iii ) sera obtained following active immunization with formalinized P. gin givalis. All assays were performed with or without the addition of hum an complement. Significantly more (P < 0.01) direct killing of P. ging ivalis occurred with immunized sera and complement than with any of th e other treatments, The sera from ligature-induced periodontitis NHPs had significantly less (P < 0.03) killing capacity than the baseline s era, which contained natural antibody produced to P. gingivalis coloni zation. Sera from immunized NHPs were used to opsonize P. gingivalis a nd caused significantly greater (P < 0.01) levels of O-2(-) release fr om PMNs. Finally, the sera from immunized NHPs significantly enhanced (P < 0.009) the uptake of P. gingivalis by PMNs, although binding of t he bacteria to PMNs was similar among all three serum types, Active im munization of NHPs with P. gingivalis elicited a functional antibody t hat enhanced direct killing, positively influenced the activation of P MNs, and enhanced the ability of PMNs to phagocytize P. gingivalis. Mo reover, antibody produced as a sequela of progressing periodontitis ap peared to lack these functions. A wide variability in functional capac ity of the sera from individual NHPs, which may contribute to an indiv idual's susceptibility to P. gingivalis-induced disease, aas noted. Th is variability suggested that results from functional tests of serum a ntibody may aid in predicting host susceptibility to disease and respo nse to therapy.