Lymphonodal response to sensitization with 2,4-dinitrochlorobenzene (DNCB) in laboratory rats

White laboratory rats were used for the experiments. Their popliteal lymph nodes were investigated after sensitization with DNCB (2,4-dinitrochlorobenzene) and i.c. injection of 3-H-thymidine and Patent Blue Violet at several intervals following the challenge with the hapten DNCB. Changes of weight of lymph nodes, further uptake of tritiated thymidine by the cells were investigated by auto -radiography, while the content of 3-H-DNA indicating an increased DNA metabolism due to blastic transformation of the small lymphocytes was determined by a liquid scintillation method. The authors found a significantly increased weight of lymph nodes and a higher percentage of labelled cells following antigenic stimulus of i.c. injected DNCB compared to non-sensitized lymph nodes of the control rats.