Demonstration of dnp groups on the draining lymph node cells of guinea pigs following skin painting with DNCB by peroxidase labelled antibody method.

The distribution of 2,4-dinitrophenyl (DNP) groups in the draining lymph nodes of guinea pigs 12 h after painting the skin with 2,4-dinitrochlorobenzene (DNCB) was examined by a peroxidase labelled antibody method using antibody against DNP groups. DNP groups were detected on cells that were found mainly in the subcapsular sinus of the lymph nodes. Electron microscopic examination showed DNP groups distributed on the surface of lymphocytes. The significance of these findings is discussed.