An exudate containing large numbers of polymorphonuclear leukocytes is a cardinal sign of gonorrhea, particularly in males. Yet the role of leukocytes in the disease is not well understood. We will investigate the chemotactic response of peripheral leukocytes from infected and noninfected males. Leukocytes will be separated from whole blood by sedimentation in dextran. These leukocytes will be suspended in modified Boyden chambers in serum from patients and from controls. Chemotaxis will be determined after stimulation by saline, casein, T1 and T4 Neisseria gonorrhoeae. Chemotactic responses will be measured with leukocytes obtained from patients at the time of their initial visit for treatment and at various times afterwards. The role of complement and prestimulation of leukocytes will be examined. Chemotactic stimulation by laboratory strains of N. gonorrhoeae will be compared to that of strains isolated from patients. The types and numbers of phagocytic cells in exudates from the patients will be measured and a phagocytic index calculated for the cellular phagocytosis of gonococci. The results of examination of exudates will be compared to those from chemotaxis to help define the role of leukocytes in gonorrhea.