Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2002
Publication Date: N/A
Unmethylated CpG motifs, a new class of immunostimulatory agents, induce both innate and adaptive immune responses, and are considered as potential vaccine adjuvants. However, the impact and safety of CpG treatment on control and elimination of pathogenic organisms in poultry has not been shown. Eimeria species are the pathogens responsible for causing coccidiosis in birds and results in a significant economical loss every year. SC and TK are two genetic chicken lines that show different disease susceptibility to Eimeria: TK is more susceptible to E. acervulina than SC chickens. The main purpose of the present study was to see whether CpG treated birds had better defensive responses to Eimeria infection, and whether CpG treatment could enhance coccidia resistance in TK chickens. A CpG-ODN designated as HuI which was previously shown to be activate HD 11 cells by us, was introduced i.v. into 6-wk-old SC and TK chickens 24 h before the oral challenge of E. acervulina (EA) at a dose of 104 organisms/bird. Body weight (BW) was recorded individually before infection and at 6th and 9th day after primary challenge. Feces were collected from 6th to 9th day after the challenge and processed for oocyst counting. The results showed that TK birds that received only PBS or control sequence had reduced BW and higher oocyst shedding between 6th and 9th days post-infection compared to the unchallenged birds. However, HuI treated TK birds not only had no reduction on BW compared to unchallenged controlsand the oocyst count of HuI treated TK birds were significantly reduced compared to PBS and control sequence treated groups. However, CpG treatment had minimal effects on BW and oocyst counts of SC birds.These results indicate that CpG is a safe immunomodulating agent and a good candidate for vaccine adjuvant for coccidiosis.