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From the Institute of Industrial Medicine, New York University Post-Graduate Medical School, New York, N. Y.
Abstract
The 2,4-dinitrophenyl group, combined with proteins through azo linkage or by substitution in free amino groups, has been studied as a determinant in the precipitin reaction. The precipitin curves obtained resemble those encountered with purified antigens of high molecular weight with the chief exception that in the region of antibody excess antigen is not completely precipitated.
Dinitrophenyl-azo-ovalbumin was a less effective precipitant than the conjugated ovalbumin in which dinitrophenyl groups were substituted in free amino groups. The former, however, was relatively more effective in precipitating antibody from antisera to dinitrophenyl-azo-proteins than from antisera prepared against amino-substituted dinitrophenyl-proteins.
The globulin fraction of pooled antisera to dinitrophenyl-bovine
globulin contained at least three species of antibodiesviz: those precipitated by bovine
globulin; those precipitated by dinitrophenyl-ovalbumin and those precipitated only by dinitrophenyl-bovine
globulin. These were present in the ratio of 1:1:1.3, respectively. After maximal precipitation with each of these antigens the supernates' binding of
-N-dinitrophenyllysine, a hapten in which dinitrophenyl is combined with lysine in the same way as in the immunizing conjugate, was determined by the method of equilibrium dialysis. The binding in the three cases, relative to the binding by the unabsorbed immune globulin, was in the ratio of 1:0.6:0.25, respectively. Hence, the antibodies precipitated by bovine
globulin had no detectable specificity for the dinitrophenyl group, and the antibodies precipitated by the heterologous conjugate (dinitrophenyl-ovalbumin) had a greater affinity for the dinitrophenyl determinant than those antihapten antibodies that required for precipitation the fully homolgous conjugate (dinitrophenyl-bovine
globulin). Antibodies with dual specificity, i.e., with one specificity for the hapten and a distinctly different one for the protein of the immunizing conjugate, were not detected.
Footnotes
1 We wish to acknowledge the support of this work by grants from the Standard Oil Company of New Jersey (New York City) and the National Microbiological Institute of the National Institutes of Health, United States Public Health Service (Grant No. 1713).
2 Present address, Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York City.
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