Cytokine Expression in Paraffin Wax-embedded Tissues from Conventional Calves

SummaryThe cross-reactivity of antibodies against human tumour necrosis factor (TNF)α, interleukin (IL)-1α, IL-1β and porcine IL-6, and the distribution of immunolabelled cells were evaluated on paraffin wax-embedded tissues from five healthy calves. The tissues were fixed in 10% buffered formalin or Bouin's solution and processed for structural studies and immunohistochemical studies by the avidin–biotin–peroxidase technique. Bouin′s solution proved to be the more suitable fixative and Tween 20 the most effective antigen unmasking technique for increasing detectable antigenicity. Constitutive expression of TNFα, IL-1α, IL-1β and IL-6 by different cell populations, mainly macrophage-like cells, was detected. Lymphoid organs displayed a higher presence of immunolabelled cells than did lung, liver or kidney. TNFα and IL-1α appeared as the predominant cytokines, especially in the gut-associated lymphoid tissue of the ileum and in the regional mesenteric lymph nodes. The results will facilitate investigation of the role of these cytokine-producing cells in inflammatory disease processes in calves.