Experiments were conducted to test whether antigenic substances rather than nonspecific stimuli are necessary for induction of γ-globulin formation and associated morphologic changes in lymphoid tissue. Diphtheria toxoid was used as the antigen, crystalline silica as the nonantigenic adjuvant. Neonatal rabbits were used as the experimental animals because of their lack of preexisting stimulation.
Stimulated lymph nodes were studied with regard to secondary nodule and plasma cell formation, and, in addition, γ-globulin production in vitro by means of autoradiography of immunoelectrophoretic patterns. Immunofluorescence studies were performed to determine presence of antibody and γ-globulin in lymph node cells.
Results indicate that antigenic stimulation is needed for the induction of the specific histologic changes associated with γ-globulin formation. γ-Globulin synthesis was more readily demonstrable than antibody formation in immature rabbits. Several possible reasons for this phenomenon are discussed.