Streptococcus sanguis: a model in the application in immunochemical analysis for the in situ localization of bacteria in dental plaque.

A review of the development of the serology of S sanguis has been presented. This species contains a group-specific antigen designated a, which appears to be a glycerol teichoic acid. It is suggested that this antigen be designated the Lancefield group H antigen. In addition, two major serotypes based on distribution of other surface antigens have been demonstrated. The grouping antiserums for S sanguis have been used to localize these bacteria in ultrastructural sections of intact dental plaque. The organisms appear antigens and seem to form pyramid-shaped microcolonies with the apex at the tooth surface and the base at the external surface of the plaque. The cells at the apex appear to have lost some surface antigens and seem to be older. The age and arrangement of the cells suggest that most plaque forms by cell division rather than by apposition of new cells from the oral cavity. If this is true, it is necessary to alter some current concepts regarding plaque development and possiby consider some different approaches to plaque control.