Tritium labeled group A streptococcal carbohydrate haptens have been prepared by incubation of acid hydrolysates of group A carbohydrate with 3H borohydride. Isolation of hapten was achieved by column and thin layer chromatography. These procedures yielded an antigenically univalent hapten, 'α hapten', with an estimated molecular weight of 1100 daltons and a rhamnose: glucosamine molar ratio of 6:1. The α hapten inhibited the binding of A carbohydrate with homologous antiserum. Comparative antibody binding studies were performed with group A streptococcal rabbit antibody preparations by using the α hapten and a synthetic 3H p nitrophenyl β N acetylglucosamine (3H pN phiNAG) hapten. These studies demonstrate that average association constants (K(o)) obtained with the α hapten are one to two orders of magnitude higher than the K(o) determined with 3H pN phiNAG. Significantly less nonspecific binding was observed with the α hapten. Binding studies with the α hapten enabled the determination of K(o) for a number of antibody preparations which failed to evidence specific binding with 3H pN phiNAG. The availability of the α hapten makes more feasible the reliable determination of K(o) for antibody prepared under various conditions.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of Immunology|
|State||Published - Dec 1 1973|
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