CHEMO-IMMUNOLOGICAL STUDIES ON CONJUGATED CARB OHYD RATE -PROTEINS XII. THE IMMUNOLOGICAL PROPERTIES OY AN ART~ICIAL ANTIO~.N

The problem of understanding the factors which govern-the im-munological specificity of bacterial polysaccharides is essentially biochemical in nature and can be approached in two ways. The chemical constitution of these complex substances may be elucidated by the classical methods of organic chemistry in the hope of correlating differences in structure with changes in specificity. On the other hand an approach may be made by rendering simple carbohydrates of known constitution antigenic through combination with protein, and correlating the specificity of the antibodies elicited with known changes in the chemical structure of the carbohydrate radicals in question. Although the latter method has certain obvious limitations , in our initial chemo-lrnmunological studies on the specificity of carbohydrates we chose the second mode of approach, for it was our opinion that without a far reaching biological understanding, a purely chemical interpretation of this important immunological problem would be sterile indeed. From initial attempts to understand the factors underlying the immunological specificity of carbohydrates certain fundamental facts have been revealed through the application of the immunochemical approach. It has been possible to demonstrate that intra-and inter-molecular differences in the configuration of mono-and disaccharides are influential in dete~inlng specificity (1). Likewise it has been found that the introduction of a labile grouping, such as the acetyl group, will alter the immunological specificity of a monosaccharide (2). More recently it was demonstrated that the conversion of the 469