RATE CONSTANT K-37 IN COMPLEMENT-FIXATION TESTS - KINETIC STUDIES ON INFLUENZA VIRUS-IMMUNE COMPLEX MODEL

  • 1 January 1976
    • journal article
    • research article
    • Vol. B127  (2) , 269-279
Abstract
A kinetic study of the fixation of complement by the influenza immune complex was performed. The autoanalyzer provided curves which could be transformed into a simple equation. The experimental graph of the complement fixation reaction is superposable on a model curve obtained by exponential dilution of complement. The mathematical formula of this exponential complement dilution fits results of complement fixation by the immune complex. The rate constant can be estimated from the tangent at the origin of the curve; it is a function of the nature of the immune system, the quantity of immune complex and the temperature. These results show that the reaction behaves according to the equations of first order kinetics. This law is therefore the same as that described for other immunological systems, i.e., seroneutralization of bacteriophage or fixation of isoagglutinins on red cells. The kinetic study leads to the proposal of the K37 value for the titration of an anti-influenza serum. It is the rate constant of the reaction at 37.degree. C and is independent of the time and temperature of the fixation system as it is of the initial quantity of complement. Increased sensitivity of the reaction does not yield by higher values of K37 but affords greater precision in its calculation.