Cellular immune responses, chemokine, and cytokine profiles in turkey poults following infection with the intestinal parasite Eimeria adenoeides

Abstract

Cellular immune responses, chemokine, and cytokine profiles were investigated in 20-d-old turkey poults following an oral infection with 12.5 × 10(3) oocysts of Eimeria adenoeides, a protozoan parasite of the genus Eimeria that develops in the ceca. Large numbers of oocysts were produced in the feces of infected birds from d 5 after infection followed by a rapid decline by d 7. Local immune activities were characterized by observing the extent of leukocyte infiltration in the ceca by histology, measuring subsets of the lymphocyte population by immunohistochemistry, and determining the relative expression of cytokines by real-time, reverse-transcription PCR. Inflammation, assessed by scoring the extent of cellular infiltration of leukocytes in sections of ceca, was significantly higher in infected poults compared with uninfected poults on d 4, 7, 9, and 11 following infection. The percent area occupied by CD4+ and CD8+ cells in the ceca was significantly greater on d 9 and 11 (CD4+) and d 11 (CD8+) in infected poults compared with uninfected controls. The relative expression of the chemokine CXCLi2 and the cytokines interleukin (IL) 1β, interferon (IFN) γ, IL13, and IL10 was investigated in tissue samples taken from the ceca. Increased expression of CXCLi2 occurred on d 4 and 7. Increased expression of IL10 and IFNγ occurred on d 4 and of IL1β and IL13 occurred on d 7 postinfection. The increased leukocyte infiltration in the ceca, alterations in the lymphocyte subpopulations, and changes in expression of chemokines and cytokines are an indication of the cell-mediated immune mechanisms occurring in the host as a result of exposure to E. adenoeides.