MEASUREMENTS OF PRECIPITIN REACTIONS BY DIFFERENCE TURBIDIMETRY - NEW METHOD

  • 1 January 1979
    • journal article
    • research article
    • Vol. 36  (2) , 293-298
Abstract
A new method for the measurement of precipitin and flocculation reactions between antibodies [Ab] and antigens [Ag] was developed. The technique, called difference turbidimetry, involves the use of tandem cuvettes providing the opportunity of using separated and unmixed Ag and Ab as blank solutions for spectrophotometric readings in the UV wavelength range. By use of this technique genuine difference turbidity spectra were recorded for the reaction between human serum albumin and rabbit-anti-human serum albumin Ig[immunoglobulin]G. Difference turbidimetry at low wavelengths (e.g., 280 nm) allows the construction of precipitin curves with a very clearly expressed zoning phenomenon at a sensitivity which in terms of Ag and Ab concentrations is more than twice the sensitivity of conventional procedures. The zone of equivalence differs when the same reaction between an Ag and its Ab is measured by difference turbidimetry, by absorbance of washed and redissolved precipitate, and by amount of precipitated Ag.