Polarographic study on interaction between human IgG and sheep antihuman IgG antiserum and its analytical application.

Abstract

The Brdiccka current (Polarographic catalytic hydrogen evolution current produced by proteins in the presence of cobalt salt) of human immunogloblin G (IgG) and sheep antihuman IgG antiserum (anti-IgG) was studied by the d.c. and differential pulse Polarographic techniques. The Brdicka current for a mixture of IgG and anti-IgG was smaller than the sum of the currents for IgG and anti-IgG. This difference was attributed to the complex formation between IgG and anti-IgG. Anti-IgG could be titrated with IgG (or vice versa) by Polarographic techniques based on the Brdicka current. The average intrinsic dissociation constant of the IgG–anti-IgG complexes was estimated from the titration curve. The Polarographic method based on the Brdicka current and coupled with immunoreaction is useful to determine trace amounts of antigen (or antibody) down to 10−10 m using the differential pulse Polarographic technique.