Studies on the cariogenic and non-cariogenic strains of Actinomyces viscosus are undertaken to provide basic information concerning peripheral structural elements of the bacterial cell wall. These peripheral structural elements are responsible for various cell surface related properties such as cell adhesion and immunological response. The first part of the study will be concerned with an extensive examination of catabolic enzymes capable of degrading the cell wall. Special emphasis will be placed upon the enzymatic degradation of peripheral cell wall components. Similarly, the catabolic degradation of extracellular polysaccharides of Actinomyces viscosus will be studied. In a complementary study to the above approach, we will concern ourselved with the biosynthesis of immunodeterminant sugars in Actinomyces viscosus and the incorporation of these sugars into the cell wall. Various attempts will be made to interfere with synthesis and/or incorporation of sugars into the cell wall. It is the objective of our studies to provide a rational biochemical basis to correlate changes in peripheral structural elements of the cell wall with altered biological response. Bacterial cells with altered cell wall structures will be tested for their immunoresponse as well as their ability to adhere to the tooth. BIBLIOGRAPHIC REFERENCE: Structural Studies on the Cell Wall of Actinomyces viscosus, C. A. Tylenda and O. Gabriel, 67 Annual FASEB Meeting 6-10 June 1976, San Francisco, Cal., Fed. Proc (In press).