The application of complement fixation to antibody weight estimates I. To soluble antigens.
A method is described for estimating early mouse IgG antibodies to the dinitrophenyl (DNP) determinant in absolute weight units. The antibodies to be measured are adsorbed quantitatively onto an appropriate immunoadsorbent such as DNP polyacrylamide. The particulate immune complexes are then incubated with a standard dilution of a potent rabbit antiserum to mouse IgG. Removal of the rabbit anti-mouse IgG (RaM) immunoglobulins by the complexes decreases the C fixing ability of the RaM supernatants reacted with C and mouse IgG. The decrements in C fixation are linearly related to the logarithm of the weight of mouse IgG. The decrements in C fixation are linearly related to the logarithm of the weight of mouse IgG  anti DNP added to the immunoadsorbent. A calibration curve is constructed with known amounts of mouse IgG )anti-NDP as measured by quantitative precipitation. Concurrent assays with the early mouse anti-DNP sera permit conversion of the losses in C fixing potencies to weight units of mouse IgG anti-DNP by interpolation on the calibration curve.
D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D000941:Antigens; D003168:Complement Fixation Tests; D003165:Complement System Proteins; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007164:Immunosorbents; D051379:Mice; D011817:Rabbits; D012756:Sheep; D012995:Solubility
D000906:Antibodies; D000941:Antigens; D007164:Immunosorbents; D003165:Complement System Proteins