Recovery of antibody activity from inactive hybrids of H and L chains.

Hybrid IgG molecules were prepared from the heavy and light chains of specifically purified antibody against two different haptens. One hybrid consisted of the H chains from the anti-p-azobenzoate antibody from one rabbit and L chains from the anti-p-azobenzenearsonate antibody from the second rabbit, and the second hybrid consisted of the opposite combination, light chains from the first rabbit and heavy chains from the second. The two hybrids were mixed at pH 8 and were found to be so stable in the mixture that even after 2 wk at 5 degrees C there was still only low hapten-binding activity toward p-iodobenzoate and p-iodobenzenearsonate. However, exposure of the mixture of hybrids to 1 M propionic acid followed by buffer at pH 8 resulted in recovery of binding activity for p-iodobenzoate and p-iodobenzenearsonate. Thus no exchange occurred between the light and heavy chains of the hybrids in the buffer, but exchange did occur on exposure to propionic acid, and this exchange favored a preferential combination among the chains in such a manner that effective antibody sites resulted.