The two-cross immunodiffusion technique: diffusion coefficients and precipitating titers of IgG in human serum and rabbit serum antibodies
Pokrić, B.; Pucar, Z.
Analytical Biochemistry 93(1): 103-114
1979
ISSN/ISBN: 0003-2697 PMID: 107826 Document Number: 148525
The 2-cross technique, a new 2-dimensional double-diffusion technique in gel plates, was applied for simultaneous determination of precipitating titers and diffusion coefficients of antigen and antibody in body fluids. The advantage of this technique is that it works without using any standard solution and ensures conditions of time-invariant sink. The theory of the technique was verified by experimental results on the precipitating system human serum-rabbit anti-human IgG in phosphate-buffered saline solution at pH 7.4. The results obtained using several modes of calculations from experimental parameters were compared and found satisfactory. The accuracy and reproducibility of the results were confirmed. At 20.degree. C the diffusion coefficient of human IgG in 10 .times.-diluted serum is (4.4 .+-. 0.2) .times. 10-7 cm2/s, while the diffusion coefficient of rabbit anti-human IgG in a purified preparation is (2.9 .+-. 0.2) .times. 10-7 cm2/s. The critical precipitating concentration of human IgG against rabbit anti-human IgG is invariable to concentration and amounts to 0.174 .+-. 0.03 mg/100 ml at pH 7.4.