Summary Experiments are described which show that animals made tolerant to a specific antigen have a total absence of response to local stimulation by that antigen. Neonatal rabbits were used as the experimental animals, because of their lack of spontaneous morphologic activity, and bovine serum albumin was used as the antigen. Tolerance was induced by intraperitoneal injection of soluble BSA, and local stimulation was by alum precipitated BSA in the footpad. Stimulated nodes were studied with regard to secondary nodule and plasma cell formation. Results indicate that tolerant animals stimulated with the antigen to which tolerance was induced lack the specific histological changes associated with γ-globulin formation. In very young animals, reactivity in regional nodes could be suppressed or markedly diminished by systemic treatment given within 24 hr of local stimulation. A proper sequence of injections will allow the demonstration of unresponsiveness within one lymph node in the presence of reactivity to the same antigen in the regional lymph node of the opposite side in the same animal.

Cohen, M. W., & Thorbecke, G. J. (1964). Specificity of Reaction to Antigenic Stimulation in Lymph Nodes of Immature Rabbits. The Journal of Immunology, 93(4), 629–636.