lar compartment, originally decreased, showed a delayed rehydration to normal levels. Hence the voluntary water intake showed more positive correlation with changes in intracellular volume than with extracellular voIume change. Fluid balance was affected both by intracellular hydration and electrolyte levels in the extracellular fluid.A number of workers have observed that antibody becomes more cross-reactive as the course of immunization is prolonged. The first observations were apparently those of Magnus' on antigenic plant-extracts. Many similar results have been obtained with antigenic cells or crude mixtures of antigens; the first evidence that reasonably pure proteins can produce the same effect was that of Wells and Osborne.2 We used 5-times recrystallized ovalbumins from hen and duck and offered additional proof' that the antibodies to a single "pure" antigen may develop a broadened reactivity as immunization proceeds. The antisera from later bleedings may show a broader equivalence-zone: and the antibody, in the zone of antigen-excess, can combine with a larger quantity of antigen?Three possible explanations of these effects have been considered ; conceivably all of them might apply in some instances.1. The antibody initially formed is directed toward a dominant determinant-group of the antigen, and, progressively, additional antibodies are formed for separate, minor determinants?' 2. The later antibodies differ from the earlier by the presence on 1 Magnna, Ber. d w t . Bot. Gesellsck., 1908, 26a, 532 (cited in2).
Heidelberger and Kendalll first showed that the variable composition of antibody-antigen ( pneumococcus 111) precipitates depends upon the proportions of antiserum and antigen, and that the precipitate formed at the equivalence-point has an approximately constant composition relatively independent of the absolute concentrations of the reagents or of the potency of any particular lot of serum.The equivalence-point ratio varies with different antigens but its systemic constancy affords an obviously important reference point for future quantitative study of certain immune reactions. One of the best studied antigens is crystalline ovalbumin, and it should be helpful to establish limits of error within which we can determine the equivalence-point ratio. Three previoqs determinations's ' 9 * varied significantly.The equivalence-point is indicated by that mixture (ratio) of s e r a and antigen in whose supernatant there remains neither antibody nor antigen or but minimal traces of both, after precipitation is complete. For several systems, including ovalbumin and its antibody, this is identical with the constant antibody ~p t i r n u m .~ Our hen-ovalbumin was recrystallized 5 times and evidence of its very high purity has been presented.' Precipitates formed in neat serum at the Dean and Webb optimum (37"C., 30') were allowed to stand in the ice box over night, centrifuged, and with thorough dispersion washed 3 times with 1 ml. chilled saline. The precipitates were dissolved in weak NaOH-and digested with 1 ml. H'SO,. Nitrogen was determined by the micro-Kjeldahl method.' The clear stock ovalbumin solutions were similarly standardized, tested for "Aided by a grant from the National Research Council.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.