Salivary Interactions with Homologous and Heterologous Strains of Oral Streptococci and Epithelial Cells

Twenty strains of oral streptococci resembling the species of Streptococcus mitior and Streptococcus salivarius were isolated from four subjects and were incubated with homologous and heterologous whole clarified saliva. Supernatants of bacterially absorbed and control saliva were analyzed in tandem crossed immunoelectrophoresis (TCIE) against a rabbit anti-human saliva antiserum. Six to eight antigens were detected. After incubation with the bacteria, the saliva supernatants showed a decrease in the number of antigens detectable by TCIE. For all four salivas tested, the homologous group of strains absorbed fewer antigens. Some of the antigens could be eluted from bacterial pellets with 1 M NaCl after repeated washings in PBS. Epithelial cells also absorbed fewer antigens from homologous than heterologous saliva.