Use of immunoglobulin coupled to agarose beads for examining the specificity of conjugates.

Preparations of purified immunoglobulins, light chains, and unrelated proteins (used as controls) were covalently linked to agarose beads and used to study the specificity of fluorescein isothiocyanate conjugates. The data demonstrate how these beads can be used to detect immunological and non-immunological reactivity in conjugates. Commercial conjugates, conjugates prepared in this laboratory, and fluorescein-labeled normal immunoglobulins demonstrated high reactivity with control beads unless chromatographed on diethylaminoethyl-cellulose to select for the proper fluorescein-protein ratio. Undesirable immunological reactivity could be demonstrated in commercial conjugates and was shown to be due to anti-light-chain antibody.