Acquisition of immunity to the protozoan parasite Eimeria adenoeides in turkey poults and cellular responses to infection

• Published in: Poultry science 2013-12, Vol.92 (12), p.3149-3157
• Main Authors: Gadde, U, Rathinam, T, Erf, G F, Chapman, H D
• Format: Article
• Language: English
• Subjects: Animals; Avian Proteins - metabolism; Coccidiosis - immunology; Coccidiosis - parasitology; Coccidiosis - veterinary; Cytokines - metabolism; Eimeria - physiology; Feces - parasitology; Female; Immunity, Cellular; Lymphocytes - metabolism; Oocysts - physiology; Organ Specificity; Poultry Diseases - immunology; Poultry Diseases - parasitology; Turkeys; Weight Gain
• ISSN: 0032-5791
• DOI: 10.3382/ps.2013-03406

Newly hatched turkey poults were infected with 10(2) oocysts of Eimeria adenoeides and subsequently reinfected with 10(3) and 10(4) oocysts at 6 and 12 d of age, respectively. Three peaks in oocyst production were observed in the feces of poults following this series of infections. A second group of poults given the same dosing regimen was challenged with 5 × 10(4) oocysts/poult at different times to evaluate the acquisition of immunity. Judging by weight gain and mortality, no protection had been acquired at 6 d of age, but partial protection was observed by 12 and 18 d of age. A third group of poults were also infected with 10(2) oocysts and subsequently reinfected with 10(3) and 10(4) oocysts at 6 and 12 d of age to evaluate cellular immune responses to infection. Sections of ceca from infected poults showed a significantly higher leukocyte infiltration on d 6, 10, 12, 16, and 18 after infection than uninfected controls. The percent area occupied by CD4+ and CD8+ lymphocytes in the ceca, as assessed by immunohistochemistry, was significantly elevated in infected poults on d 12, 16, and 18. The relative expression of chemokine CXCLi2, and cytokines IL1β, IFNγ, IL10, IL13, IL2, IL12b, and IL18 was measured by real-time reverse-transcription PCR. The expression of CXCLi2 and IL10 was found to be elevated on d 12, and IFNγ on d 10, 12, and 16. Expression of IL13 and IL18 was increased on d 10 and IL2 on d 10 and 16, and that of IL12b on d 16 in infected poults. Increase in the infiltration of leukocytes, percent area occupied by CD4+ and CD8+ lymphocytes, and changes in the relative expression of cytokines in the ceca characterize the dynamics of immune responses in turkey poults infected with E. adenoeides early in life.