Changes Of Immunologic Function And Expression Of IL-2 MRNA In Immune Organs Of Probiotics-fed Chicks After ND Vaccination

To reveal the influence of probiotics on ND-vaccine and the cellular and humoral immunity in immune organs of chicks and to provide a scientific and experimental evidence for the development of probiotics, investigations about the dynamic changes of the proliferative function, the quantity of T and B lymphocytes and the expression of IL-2 mRNA in immune organs (thymus, bursa and spleen) of chicks were carried out. One-day-old chicks fed with probiotics and then inoculated by ND-vaccine and following challenged with virulent NDV were used in this study, and also technology of cell culture, MTT, histochemistry staining and real-time fluorescence quantitative PCR were used. The results were as follows:1. Compared with controls, the quantity of TANAE+ cells in immune organs of chicks increased persistently and differed remarkably at 7~14 days (P<0.05 or P<0.01); the proliferative function of T-lymphocytes in thymus and spleen were much stronger than that of controls and differed remarkably at 4~7 days (P<0.05 or P<0.01); the proliferative function of B-lymphocytes in bursa and spleen was much stronger than that of controls and differed remarkably at 4~14 days and 4~7 days, respectively. These results indicated that the function of cellular and humoral immunity in immune organs of probiotics-fed chicks strengthened remarkably.2. After the inoculation of ND-vaccine, the proliferative function of T and B lymphocytes and the quantity of TANAE+ cells in immune organs of probiotics-fed and ND-vaccinated chicks differed remarkably from controls and was stronger or higher than that of ND-vaccinated group. The results indicated that the application of probiotics combined with ND-vaccine could promote the level of cellular and humoral immunity which indicated that the cellullar immunologic response and humoral immunoresponse in probiotics-fed and ND-vaccinated chicks were strengthened by probiotics.3. After the application of probiotics combined with ND-vaccine, the expression of IL-2 mRNA in immune organs differed remarkably from controls and ND-vaccinated group, which indicated that both probiotics and ND-vaccine could stimulate the activation and proliferation of T cells and promote the expression of IL-2 mRNA and strengthen the immunological regulation of molecular immunity. The cellular immune response and humoral immunoresponse in probiotics-fed and ND-vaccinated chicks differed significantly, which indicated that the probiotics could promote the immunological regulation of cytokine IL-2 mRNA. 4. After the challenge of virulent NDV, the proliferative function of T and B lymphocytes in immune organs, the quantity of TANAE+ cells and the expression of IL-2mRNA are all stronger or higher than that of controls. The application of probiotics combined with ND-vaccine showed effectively. These indicated that the probiotics could not only strengthen the level of cellular and humoral immunity, but also strengthen the cellular immune response and humoral immunoresponse against ND-vaccine by great secretion of cytokine and specific antibodies.5. After the challenge of virulent NDV, the morbidity of chicks of controls was 100% and all chicks died ultimately with typical symptoms of ND. The morbidity in probiotics-fed group, ND-vaccinated group and probiotics-fed and ND-vaccinated group were 60%, 20% and 0%, respectively and there is no death in any of these groups. The results showed that both probiotics and ND-vaccine could promote the immunity of organism and resistance against NDV, the coalescent application of probiotics and ND-vaccine showed better effect than each of them, which indicated that the promotion of probiotics on specific immune protective contribution of vaccines.