Immunologic Changes And Mechanism Of Peripheral Blood And Immune Organs In Chicks Infected With Eimeria Necatrix

In this study, staphytococcal protein A(SPA) rosette test, indirect enzymelinket immunosorbent assay(IELISA)and immunohistochemistry ABC were used to research the dynamic changes of the number of T or B lymphocytes and the content of immunoglobulin (Ig) G, IgM, IgA in peripheral blood, the number of CD4+, CD8+ lymphocyte subpopulation, TANAE+ cells and IgG, IgM, IgA antibody-producing cells, the ratios of CD4+ and CD8+ T cells in immune organs (thymus, bursa of Fabricius and spleen) of chicks primary and secondary infected with Eimeria necatrix (E.necatrix) respectively in order to reveal mechanism of protective immunity of chicks infected with E.necatrix and offer important theory for development coccidiosis vaccine. The results were as follows:①　The numbers of T, B lymphocytes and the content of IgG, IgM, IgA in peripheral blood, the number of CD4+, CD8+ lymphocyte subpopulation, TANAE+ cells and IgG, IgM, IgA antibody-producing cells, the ratios of CD4+ and CD8+ T cells in immune organs of chicks primary infected with E.necatrix were increased compared with controls 7~21 days postinfection (PI) in different degree. The number increased significantly in a peak around 14~18 days PI. The observations showed that cellular and humoral immune function in peripheral blood and immune oranges of chicks primary infected with E.necatrix were enhanced.②　The numbers of T, B lymphocytes and the content of IgG, IgM, IgA in peripheral blood, the number of CD4+, CD8+ lymphocyte subpopulation, TANAE+ cells and IgG, IgM, IgA antibody-producing cells in immune organs of chicks secondary infected with E.necatrix were decreased compared with primary infected chicks 2~7 days PI in different degree. Thereafter they begin to increase. The number increased significantly compared with controls and primary infection chicks 10~14 days PI. The results indicated that immune function of chicks challenged with high doses sporulated oocysts was decreased transitory but the chicks were well protected because of cellular and humoral immune levels excited by primary infected. On the other hand, cellular and humoral immune levels of chicks secondary infected with E.necatrix were increased significantly in later time which indicated that immune recall response was came into being. The cellular immune level was earlier enhanced than the humoral immune level in chicks infected with E.necatrix. The results indicated that cellular immune was one of the most important factors in inducing and assisting humoral immune function enhanced. In addition, CD4+ T cells made an important role in initiating primary immune respond and CD8+ T which decreased slightly and increased rapidly was the leading factor in resisting secondary infection. Candidate: Liu Jing Speciality: Basic Veterinary ScienceAdvisor: Zheng Shimin...