IMMUNOHISTOCHEMICAL DETECTION OF CYTOKINES IN PARAFFIN-EMBEDDED MOUSE-TISSUES

We have successfully developed a method for the immunohistochemical de tection of interleukin 2 (IL-2), IL-4, IL-6, IL-10, IFN gamma and TNF alpha using monoclonal antibodies (MAb), in sections of mouse tissue e mbedded in paraffin wax. The method involved fixation in periodate-lys ine-paraformaldehyde (PLP), rapid dehydration and infiltration under v acuum with paraffin wax at 54 degrees C. Comparative observations demo nstrated that the method gives equivalent or better results than forma ldehyde fixed, frozen sections. Since reliable controls: both positive and negative, are paramount for interpretation of immunohistochemical staining, such controls were determined. The following tissues were s hown to be suitable as positive controls when using paraffin-embedding : spleen for the detection of TNF alpha, small intestine for IL-2, IL- 4 and IL-10, and HSV-1 infected eyes for IL-6 and IFN gamma. We conclu de that PLP fixation and low temperature paraffin-embedding is a metho d which provides both preservation of excellent tissue morphology and reliable immunohistochemical identification of cytokines. These attrib utes will be invaluable in a wide variety of experimental situations. (C) 1997 Elsevier Science B.V.