Immunochemical studies on a laminaribiosyl-azoprotein conjugate

Laminaribiose ( 3-o-β- d-glucopyranosyl- d-glucose ) was coupled to bovine serum albumin (BSA) by an azophenyl linkage to provide the synthetic antigen BSA-p-phenylazo-β-laminaribioside. The behavior of antisera prepared in rabbits immunized with the β-laminaribiosyl conjugate was examined by immunodiffusion, quantitative precipitation and hapten inhibition. Anticonjugate absorbed with carrier protein showed the greatest reactivity with the homologous β-laminaribiosyl-BSA antigen, but also showed some cross precipitation with β-cellobiosyl, β-sophorosyl and β-gentiobiosyl-BSA conjugates. Glucobioses linked through the β-(1 → 2), β-(1 → 3), β-(1 → 4) and β-(1 → 6) positions, as well as laminaridextrins and tri and tetrasaccharides of β-linked glucose possessing a laminaribiose moiety either at a nonreducing end location or at a subterminal location, were assayed for their ability to inhibit antilaminaribioside precipitation. Hapten inhibition data showed anticonjugate a possess a high degree of specificity directed against the terminal nonreducing β-laminaribiosyl end group.