Platelet responses and anaphylaxis-like shock induced in mice by intravenous injection of whole cells of oral streptococci.

Intravenous injection of lyophilized whole cells of various oral streptococcal strains into muramyldipeptide (MDP)-primed C3H/HeN mice induces rapid anaphylactoid shock. Here we examined the mechanism underlying this shock. In non-primed mice, Streptococcus intermedius K-213K (SiK213) and Streptococcus constellatus T21 (ScT21) produced little or no sign of shock. In MDP-primed mice, SiK213 caused lethal shock, while ScT21 only had a weak effect. SiK213 induced decreases in blood platelets and 5-hydroxytryptamine (5HT) preceding the shock, while the effects of ScT21 were weak. The SiK213-induced 5HT decrease and shock were reduced by a complement-C5 inhibitor. These results suggest that (i). streptococcal bacterial cells can induce rapid platelet responses, (ii). complement-dependent degradation of platelets may be involved in streptococcus-induced shock, (iii). the streptococcus-induced platelet degradation or degranulation may occur largely in the systemic circulation, and (iv). platelets may play a role not only in infectious diseases caused by gram-negative bacteria, but also in diseases caused by gram-positive bacteria.

Immunobiological activities of bacteria isolated from the root canals of postendodontic teeth with persistent periapical lesions.

Although intraradicular bacteria are widely considered to be the primary etiological agents of periapical lesions, the immunobiological properties of the species in question are not adequately known. The aim of this study, therefore, was to investigate the pathobiological properties of the 10 most frequently isolated endodontopathic bacterial species. Using cellular components of the pathogens obtained by sonic extraction, we have investigated their ability to induce monocyte migration, interleukin 1 production, mitogenic responses of lymphocytes, and the polyclonal activation of B lymphocytes. It was found that all of the tested species enhanced the migration of monocytes and induced mitogenesis in B lymphocytes. The polyclonal activation of B cells and the induction of interleukin 1 by monocytes were found to be stronger in Gram-negative anaerobes. Furthermore, all of the tested species excluding Bacteroides oralis were poor T cell mitogens. These findings show that a wide range of pathobiological properties are attributable to the most frequently isolated endodontic pathogens. It thus seems plausible that a battery of complex immunological responses induced by such microbes lead to the formation of persistent periapical lesions.