Blastogenic response of human lymphocytes to oral bacterial antigens: characterization of bacterial sonicates

Soluble sonicate supernatant preparations were made from Actinomyces viscosus (ATCC 19246), A. naeslundii (ATCC 12104), two strains of Veillonella alcalescens (strain HV-1 and a human oral isolate), Streptococcus sanguis (ATCC 10556), S. mutans (strain 6715-T2), Bacteroides melaninogenicus (strain K110), and Leptotrichia buccalis (isolated from human dental plaque). These supernatants were characterized with reference to their chemical and antigenic components and their biological activity determined by using in vitro lymphocyte blastogenesis as a measure of the host's cellular immune response. The sonicate supernatant of each bacterium contained protein, neutral sugars, methylpentose, and nucleic acids. Protein was the major component in all except L. buccalis, in which neutral sugars predominated. The antigenic components in each supernatant were detected by using rabbit antisera prepared against the whole bacteria and the sonicate supernatant. The supernatants showed a complex antigenic distribution on immunoelectrophoretic analysis. The supernatants were shown to be antigenic and not mitogenic in nature, since neither cord blood lymphocytes nor all adult lymphocytes were stimulated. The supernatant antigen preparations showed a reproducible, dose-dependent, and kinetic response in vitro, which was similar to that seen with the antigen preparation streptokinase-streptodornase.