title: Failure of the usual anti-Ig antibody method for quantitative measurement of low affinity antibodies.
abstract: The usual anti-Ig antibody method, consisting of the precipitation of soluble antigen-antibody complexes by heterologous anti-Ig antibody, was applied for quantitative estimation of guinea pig IgG2 anti-ovalbumin and anti-2,4-dinitrophenyl (DNP) antibodies by measuring the maximum amounts of antibody-bound antigens. However, the amounts of antibodies estimated were less than those obtained by other methods: the precipitin reaction, the precipitation of antigen-antibody complexes with 50% saturated ammonium sulfate, and equilibrium dialysis. In particular, the anti-Ig antibody method greatly underestimated the amount of anti-DNP antibody with low affinity for epsilon-DNP-L-lysine. Thus, it was concluded that partial dissociation of the antigen-antibody complexes occurring upon precipitation with anti-Ig antibody made the anti-Ig antibody method unsuitable for quantitative determination of antibodies.
mesh_terms: D000818:Animals; D000906:Antibodies; D003956:Dialysis; D004140:Dinitrophenols; D006168:Guinea Pigs / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis*; D008832:Microchemistry; D010047:Ovalbumin; D011233:Precipitin Tests; D012710:Serum Albumin, Bovine
chemical_list: D000906:Antibodies; D004140:Dinitrophenols; D007074:Immunoglobulin G; D012710:Serum Albumin, Bovine; D010047:Ovalbumin