Figure 2.

Purity and light-chain specificity of purified polyclonal IgG4κ, IgG4λ and IgG4κ/λ hybrids. (a) Direct ELISA; purified IgG4 protein were bound to ELISA plates and probed with serially diluted antisera against IgG4 (▲), total light chain κ (•) or λ (▪).(b) IgG-capture ELISA; serially diluted purified IgG4κ (•), IgG4λ (▪) and IgG4κ/λ (▲) were captured by anti-IgG-coated microplates and probed with antisera against IgG4, total light-chain κ or λ, as indicated. These graphs are representative figures for all the different IgG4 pools. (c) IgG4 purity analysed by Western blotting and Coomassie stain. 0·5 μg protein/lane was analysed non-reduced by SDS–PAGE and immunoblotted with antisera against IgG4, total light-chain κ or λ as indicated. One microgram was loaded either reduced or non-reduced and stained with Coomassie blue.