Immunochemical studies on dextrans. Two distinct alpha 1 linked to 3 specificities of rabbit anti-dextran B1355

Rabbit anti-dextran B1355 sera prepared by injecting rabbits with Leuconostoc mesenteroides NRRL B1355 were separated on a Sephadex G75 column into two fractions, one binding and the other not binding to the column. Oligosaccharide inhibition of precipitation of the two fractions with dextran B1355 indicated that both fractions had alpha 1 linked to 3 specificity. However, antibodies in the non-binding fraction were shown to be directed against O-alpha-D-glucopyranosyl-(1 linked to 3)-O-alpha-D-glucopyranosyl-(1 linked to 6)-D-glucose, while those in the binding fraction were directed against O-alpha-D-glucopyranosyl-(1 linked to 6)-O-alpha-D-glucopyranosyl-(1 linked to 3)-D-glucose. These results are consistent with the proposal of Bhoopalam et al. (Proc. Soc. Exp. Biol. Med. (1979(=) 161, 430-434) that there are different epitopic groups on this dextran.