Measurement of antibody and antigen concentrations with a sodium sulphate glutaraldehyde technique

Gamma-globulins can be crosslinked at low concentrations by simultaneous treatment with sodium sulphate and glutaraldehyde (SSG-method). This precipitate can be used for the assay of antibody or antigens. Examples are given for the measurement of (1) anti-dinitrophenyl antibody by reaction of the precipitate with 125I-dinitrophenylovalbumin, (2) IgA by inhibition of an anti-IgA precipitate with an 125I-labelled IgA myeloma protein, (3) idiotypic antibody by inhibition of the binding of a 125I-labelled myeloma protein by an anti-idiotype precipitate.