The Specificity of Antigen-Induced Thymidine-2-14C Incorporation into Lymph Node Cells from Sensitized Animals

Abstract

Studies of the immunochemical specificity of antigen-induced thymidine-2-¹⁴C incorporation in lymph node cells obtained from animals sensitized to α,DNP(Lys)_11–15 or α,DNP(Lys)₉ have led to the following observations. 1) Only immunogenic members of the homologous series of α,DNP-L-lysines, equal to or larger in size than the heptamer, stimulate the incorporation of thymidine-2-¹⁴C into specifically sensitized cells. 2) Nonimmunogenic α,DNP-L-lysines neither stimulate these cells nor prevent stimulation by immunogenic peptides. 3) The specificity of the receptor for antigen on the sensitized lymphoid cell contrasts with the previously observed capacity of anti-α,DNP(Lys)_n antibody to react with DNP-containing proteins and nonimmunogenic α,DNP-L-lysines, but parallels the specificity of the in vivo delayed or anamnestic response. These results provide support for speculations concerning the existence of a still undefined molecule, different from antibody, which functions as the cellular-receptor for antigen and regulates the proliferative and biosynthetic response of the cell.