Cell interaction in the secondary immune response

Abstract

This paper investigates the necessity for cell interaction in the in vitro secondary immune response of rabbits to sheep red cells, and attempts to identify and quantify the cells involved. The observed relation between cell dose and response is in good agreement with theoretical predictions from hit theory, and indicates that at least three cell types, an antibody precursor cell and two cooperating cells, are required to initiate both IgM and IgG memory responses. The antibody precursor cells appear restricted to one immunoglobulin class. The addition of thymus cells to cultures where the cooperating cells are in short supply compensates for the shortage. Immunological memory is attributable to a significant increase in the number of both the antibody precursor cell and a cooperating cell. Both cells migrate from the spleen to other peripheral lymphoid tissues. IgM precursor cells persist for some month but are inhibited from responding to new antigen by small amounts of specific IgG.