Search

BACKGROUND: Ex vivo whole blood stimulation assays (WBSA) have been used to characterize the cytokine response to diet in cats. The present study aimed to use this assay to determine the cytokine response to diets being fed at the time of diagnosis to dogs with chronic enteropathy (CE) and to compare this to a control group of dogs presented for non-gastrointestinal (GI) causes.RESULTS: Dogs with chronic GI signs and dogs presented for non-GI causes were prospectively recruited. For each case, residual blood following diagnostic sampling was placed into heparin. WBSAs were performed using crude extracts of the diet currently being fed and provided by the owner. Supernatants were collected and analyzed for tumor necrosis factor (TNF)-alpha, interleukin (IL)-10 and IL-4 using an enzyme-linked immunosorbent assay. The case group consisted of 22 dogs with CE diagnosed on histopathology of GI biopsy and 9 with suspected CE. The non-GI group consisted of 18 dogs. Of the diets being fed at or prior to diagnosis, hydrolyzed protein diets elicited significantly lower IL-10 and TNF-alpha concentrations compared to commercial intact protein diets in dogs with confirmed or suspected CE (P-value 0.004 and CONCLUSIONS: Hydrolyzed protein diets elicited a significantly reduced cytokine response when incubated with patient whole blood ex vivo compared to commercial intact protein diets in dogs with CE. The IL-4 to IL-10 ratio as a marker of dietary responsiveness warrants further investigation, together with assessment of the cytokine response to diet at the intestinal mucosal surface.

To characterize the immune response associated with Lawsonia intracellularis infection, twenty-eight, 7-week-old pigs were dosed orally with a pure culture of L. intracellularis. Animals were killed 3, 7, 14, 21, 28, 35, and 42 days postinfection. Light microscopic studies were undertaken to immunophenotype the immunologic response using specific antibodies to T-cell subsets (CD3, CD4, and CD8), B cells, major histocompatibility complex class II, cadherin, and macrophages over the course of time. The results indicate that there is a direct association between the presence of L. intracellularis and reduced T-cell and B-cell numbers. For the first time, this provides evidence of the presence of an immunosuppressive mechanism operating in this disease. Furthermore, macrophage marker studies indicated that macrophages may play a more complex and significant role in the disease process than has been previously reported, with activated macrophages accumulating in infected hyperplastic crypts.