The role of intestinal intraepithelial lymphocytes in resistance against coccidiosis in chickens

Abstract

Abstract Coccidiosis is a critical enteric disease that costs more than $14.5 billion in annual cost to world poultry industry. It is caused by different Eimeriaspecies that invade and replicate within the intestinal epithelium in a site-specific manner. The Eimeriainfection induces local intestinal damage, reduces feed consumption, feed utilization, and growth performance, and increasing mortality rate. With the recent antibiotic ban including anticoccidial drugs in chicken production, the live vaccination become widely used to control coccidiosis. However, the live vaccines are expensive, require time to circulate in the host to induce a protective immunity, and process a high-risk factor for necrotic enteritis caused by clostridium perfringens. Therefore, there is a high demand for development of safe, protective, and inexpensive vaccines against coccidiosis which require better understanding of host immune responses to Eimeria parasites. The aim of this study is to elucidate the protective role of intestinal intraepithelial lymphocytes (IELs) during the Eimeriainfection. At 3 week of age, SPF white-leghorn chicks were divided into 3 groups. Each group (n=50) was orally inoculated with 20,000 oocytes of Eimeria (E) acervuline or E. maxima, or mock-inoculated with PBS. At 2 day post-infection (dpi), 7 dpi and 14 dpi, the frequency and the number of small intestinal IEL populations were determined by a flow cytometry. Eimeriainfection induced the number of TCRγδ +, TCRβ +, TCR neg, TCRβ +CD4 +, TCRβ +CD4 +CD8α +, TCRβ +CD8αβ +, TCRβ +CD8αα +, and iCD8α IELs compared to the control group at 14 dpi. However, there was no difference among groups at 2 and 7 dpi. More experiments are underway to determine the effector and function of each subset of IELs. Startup funding, The OSU