Immune Responses In Chickens Against Eimeria Tenella And E.maxima

The changes of mucosal immunity and cell mediated immunity after AA chicken was infected with Eimeria tenella, Eimeria maxima live vaccines and their precocious vaccines were examined. The importance of mucosal immunity and cell-mediated immunity against Eimeria was proved. Both live vaccine and precocious vaccine can stimulate immune response effectively.The effect of oral infection and subsequent challenge with Eimeria vaccines on the populations of CD4+, CD8+T lymphocytes in the intestine, cecal tonsils and spleen of chickens was assessed by immunohistochemistry. Immediate and significant increase of CD4+ cells after primary infection was observed, whereas nonspecific increase post challenge was found. The rapid and considerable increase of CD8+ cells occurred post challenge , whereas no remarkable increase after primary infection occured. No notable differences were observed between the immune responses against live and precocious vaccines. The immune response in the intestinal mucosal against E.maxima was intenser than E. tenella.The observation in the length of intestinal villus by HE stain prove that the Eimeria vaccines cause some damage which can be recovered at 12 and 4 days post primary infection and challenge infection respectively.Lymphocyte proliferation assay was used for the assessment of cellular responses. The results showed that lymphocyte responses increased post infection. The response level of chicken post challenge was higher than the level without challenge. The response level of chicken immuned by live vaccines was higher than those who was immuned by precocious vaccines. The response level of chicken immuned by E.maxima was higher than those who were immuned by E.tenella.