Electron-microscopic demonstration of Streptococcus mutans in 5-day-old experimental dental plaque using immunohistochemistry.

The present work described the distribution of horseradish peroxidase reaction product obtained after immunohistochemical staining of consecutive ultra-thin sections of 5-day-old experimental dental plaques using differently absorbed anti-S.mutans sobrinus, anti-S.mutans mutans, and normal rabbit lambda-globulins. It was found that an in situ identification of S.mutans subspecies sobrinus could be obtained using thoroughly absorbed anti-S.mutans sobrinus gamma-globulins and consecutive sections. The anti-S.mutans mutans gamma-globulins were after tests on pure cultures of several oral bacteria found to cross-react with S.milleri. Furthermore, crude and absorbed normal rabbit gamma-globulins were observed to contain antibodies that cross-reacted with several plaque microorganisms.