Preferential recombination of antibody chains to form effective binding sites.

The recovery of hapten-binding activity by a mixture of H and L polypeptide chains of the whole gammaG-immunoglobulin fraction from rabbit anti-p-azobenzenearsonate (Rp) serum is almost as great as that by a mixture of H and L chains from specifically purified Rp antibody. Random combination among the H and L chains from the anti-Rp antibodies and the normal gammaG-immunoglobulin present would result in little recovery of hapten-binding activity. This suggests a preferential recombination of H and L chains from antibody. Mixtures of H or L chains from anti-p-azobenzoate (Xp) antibody and the complementary chains from antibody-depleted gammaG-immunoglobulin show little hapten-binding. When anti-Xp antibody H chains are added to mixtures of one equivalent of anti-Xp L chain and increasing amounts of non-specific L chain, the hapten-binding by the mixtures decreases, but not as much as if the H chains combined with the L chains randomly. Hapten was not present during these recombination procedures. These data indicate that in the cases of anti-Xp and of anti-Rp antibodies, there is a selective combination between those H and L chains which give effective hapten binding regions.