Molecular Restriction of Anti-hapten Antibody elicited in Neonatal Rabbits

Abstract

THE origin of the diversity of antibody combining sites is one of the crucial questions of immunology. Many workers, hoping for evidence from structural studies of homogeneous antibodies, have attempted to elicit antibodies with restricted heterogeneity^1–6. Another approach to the problem is to study the ontogeny of antibody diversity^7–10. These and other approaches have been hindered by inadequate criteria for judging antibody heterogeneity. Techniques for the direct analysis of isoelectric heterogeneity of specific antibodies (A. R. W., in preparation) have facilitated the search for homogeneous antibodies and made it possible to study developmental aspects of diversity. These two approaches are combined in the studies we report here on the anti-hapten antibodies produced by neonatal rabbits. We have found that in the initial response to a heterogeneous presentation of hapten, neonatal rabbits frequently produce anti-hapten antibodies with restricted isoelectric spectra. The term “restricted” is used relative to the spectra of antibodies produced in adult animals. In certain neonates, the antibody spectrum resembled that characteristic of a single clone (monoclonal antibody).