Title: Chicken IL-17F: Identification and comparative expression analysis in Eimeria-Infected chickens Authors
Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 23, 2013
Publication Date: December 23, 2013
Citation: Kim, W.H., Jeong, J., Park, A.R., Yim, D., Kim, Y., Kim, K.D., Chang, H.H., Lillehoj, H.S., Min, W. 2013. Chicken IL-17F: Identification and comparative expression analysis in Eimeria-Infected chickens. Developmental and Comparative Immunology. 38(3):401-9. doi: 10.1016/j.dci.2012.08.002. Interpretive Summary: Many poultry diseases affecting the gut induce severe inflammation that destroys the integrity of the intestinal wall, reducing its ability to absorb nutrients. Inflammation also exerts negative consequences on animal productivity and retards growth. In this paper, an ARS scientist collaborated with scientists at a Korean University to characterize a poultry cytokine which induces inflammation. This was done by cloning one of the IL-17 family cytokines designated as interleukin-17F (IL-17F), a proinflammatory cytokine that plays an important role in gut homeostasis. A complete gene sequence of chicken IL-17F (chIL-17F) gene was isolated from activated lymphocytes from spleen and it showed 53% amino acid sequence identity with the previously described chicken IL-17 (chIL-17A) and 38-43% to mammalian homologues. Interestingly, the expression of chIL-17F, as measured by quantitative real time PCR, was restricted to intestinal areas parasitized by E. maxima and E. tenella infections. These results suggest the possibility that chIL-17F is involved in mediating local inflammatory responses to Eimeria infection. Futher studies to investigate the role of chIL-17 and its related IL-17 cytokines in enteric diseases like coccidiosis will enhance our ability to develop a strategy to decrease harmful inflammatory response associated with parasitic diseases, which will benefit the poultry industry, improve veterinary health, and reduce the demand for antibiotic use in poultry production.
Technical Abstract: Interleukin-17F (IL-17F), belonging to the IL-17 family, is a proinflammatory cytokine and plays an important role in gut homeostasis. A full-length chicken IL-17F (chIL-17F) cDNA with a 510-bp coding region was first identified from ConA-activated splenic lymphocytes of chickens. The chIL-17F shared 53% amino acid sequence identity with the previously described chicken IL-17 (chIL-17A) and 38-43% to mammalian homologues. Interestingly, synteny analysis indicated that the locus harboring chIL-17 and chIL-17F displayed inverted order compared to those of mammals. Expression of chIL-17F transcripts was high in the lymphoblast cell line CU205 and at moderate levels in the small and large intestines and liver. Expression profiles of chIL-17F and chIL-17 were examined in mitogen-stimulated splenic lymphocytes and in the intestinal areas affected with E. maxima and E. tenella infections using quantitative real-time PCR. Expression levels of chIL-17F, like chIL-17, were generally elevated in mitogen-activated splenic lymphocytes. However, chIL-17F and chIL-17 expression levels were differentially regulated in the intestinal tissues affected with E. maxima and E. tenella infections. Expression of chIL-17F was upregulated, but chIL-17 was not. Biological activity of recombinant chIL-17F is similar to that of chIL-17 in primary chicken embryonic fibroblasts. These results suggest the possibility that chIL-17F is similar and/or unsimilar to roles of chIL-17 and plays important functions in mucosal immunity to intestinal intracellular parasites such as Eimeria. Key words: chicken, cytokines, IL-17F, Eimeria infections.