title: Isolation and immunochemical characterization of rabbit 7S anti-IgG with restricted heterogeneity.
abstract: 7S anti-IgGs were isolated from four rabbit antistreptococcal antisera by the use of immunoabsorbent columns. The isolated proteins were of restricted molecular heterogeneity; they formed a monodisperse band on microzone electrophoresis and had a limited number of light chain bands when analyzed on urea polyacrylamide gel. The binding site of the 7S anti-IgGs was detected in the F(ab')(2) portion of the molecule. The binding site has antibody specificity for the Fc portion of IgG. For one 7S anti-IgG the combining site on the Fc portion could further be defined. A pepsin fragment of Fc, described as Pep-III', was a potent inhibitor of the coprecipitation of 7S anti-IgG with antigen-antibody complexes. An idiotypic cross-reaction was detected between the 7S and 19S anti-IgGs isolated from the same rabbit with anti-idiotype sera prepared in guinea pigs. This idiotypic specificity was not detected in the 7S anti-IgGs of 20 other rabbits.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000302:isolation & purification*; D000936:Antigen-Antibody Complex; D001428:Bacterial Vaccines; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera / Q000032:analysis; D007120:Immunochemistry; D007074:Immunoglobulin G / Q000032:analysis / Q000302:isolation & purification*; D007075:Immunoglobulin M / Q000302:isolation & purification*; D007519:Isoantigens / Q000302:isolation & purification; D011233:Precipitin Tests; D011817:Rabbits; D011863:Radioimmunoassay; D013291:Streptococcus / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000936:Antigen-Antibody Complex; D001428:Bacterial Vaccines; D007106:Immune Sera; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007519:Isoantigens