Antibody binding of cartilage-specific proteoglycans

Antiserum to cartilage-specific proteoglyean from chickens contains IgG which binds embryonic [ 35S]sulfate-labeled cartilage-specific proteoglyean ([ 35S]PGS I). The binding of antibody to [ 35S]PGS I does not require prior digestion of the antigen with testicular hyaluronidase or chondroitinase ABC. Presence of [ 35S]PGS I in the antigen-antibody reaction product was demonstrated using the precipitation method of Farr and confirmed by demonstrating that goat anti-rabbit IgG serum can precipitate rabbit anti PGS I—[ 35S]PGS I complexes but not [ 35S]PGS I alone. The antibody can bind essentially all (>90%) of the [ 35S]PGS I. Antibody can bind to [ 35S]PGS I in either the monomeric or the aggregated form. The antiserum does not contain antibodies to a number of glycosaminoglycans, to proteoglyean from skin or to a minor proteoglyean component of cartilage (PGS II). The antiserum cross-reacts with cartilage-specific proteoglycan from a different avian genus, the Japanese quail.