Clonal Restriction of the Immune Response to Phosphorylcholine

Abstract

THE antibody response to most antigens is chemically heterogeneous, reflecting clonal heterogeneity of the responding cells. This heterogeneity may arise in part from the number of different epitopes present in the structure of complex antigens, although the antibody response even to chemically simple haptens (which may contain more than one epitope) is often very heterogeneous. For example, the dinitrophenyl hapten on a protein carrier elicits many different anti-hapten antibodies which are distinguished by isoelectric focusing¹. Also, individual mice respond to the p-azobenzoate and to the p-azophenylarsonate haptens by producing a population of serum antibodies with many idiotypic specificities². Certain carbohydrate antigens, however, seem to induce relatively homogeneous antibody responses^3,4. One of these antigens, the C-polysaccharide from the rough strain of pneumococcus R36A, induces a restricted antibody response directed against phosphorylcholine⁵, a structural component of the C-polysaccharide⁶.