Precipitin Testing with Special Reference to the Photoelectric Measurement of Turbidity

[摘要] The photoelectric measurement of turbidities (by use of the Libby photron-reflectometer) developing in the precipitin reaction has been found to be correlated with the nitrogen contents of the precipitates formed in protein antigen-antibody systems, and with the total amount of antigen and antibody precipitated in the case of the SIII-antibody system. Antisera prepared in rabbits to purified SIII, beef albumin, beef globulin II, pumpkin seed globulin, and Panulirus argus serum have been tested. The amounts of turbidity developed are decreased with increased NaCl concentration or with increased pH within the limits tested. Increased reactivity of beef globulin II followed Bloor's mixture extraction of the dried reagent.In all cases the effects of environmental factors on the reaction, or chemical treatments of the antigens, are predominantly shown in the zone of antigen excess, and the chief implication of this knowledge is that the whole or normal titration curve of constant antiserum with varied antigen from prozone to postzone is the minimal knowledge upon which valid conclusions relating to precipitin testing may be based.Many reasons are given as to why the use of such normal titration curves is advantageous, since their determination by photoelectric turbidimetry is accurate and relatively easy under conditions described herein. The errors due to fragmentary comparisons of single points or portions of curves, which may even be noncomparable ones, will thus be avoided.

[学科分类] 生物科学（综合）