A review of adaptive immune responses to Eimeria tenella and Eimeria maxima challenge in chickens

Adaptive immune responses in poultry against the invading parasites are complex, involving both specific and non-specific immunity. Attempts in finding new vaccine candidates for Eimeria parasite infection control are continuing, and any promising candidates that have been discovered so far are only effective against homologous infection. Different genes are involved in coccidiosis protection and take part in Eimeria infections. Expression library immunisation (ELI) is a novel method for systematic screening of genomes to identify new vaccine candidates. Some of these antigens have yielded promising results, with rEtIMP-1 and EtIMP1-CD40L reducing oocysts output with 66 and 78%, respectively, in chickens challenged with Eimeria tenella by inducing immune responses. The significance of cytokines in inducing immunity against the invading parasite cannot be ignored, as they provide support to both innate and adaptive immune responses. Adaptive immune responses and genes expressed in response to E. maxima and E. tenella challenges are important. Possible immunogenic vaccine candidates derived from Eimeria antigens have potential for control, diagnosis and treatment strategies for coccidiosis.