Effect Of ND Vaccine On The Development Of T Lymphocyte And Immune Function In The Chicken

SPF chickens on the 18-day old embryonic day and 1,4,7,14,28,56,84,120 post-hatching day were choiced,were divided into immuized group immunized with weak toxicity ND Lasota live vaccine and control group did nothing.Thymus and spleen of chickens after immunized 10 days were removed and made cryosections for HE stain and immunohistochemistry.Meanwhile another thymus and spleen were selected sterilly to separate lymphocytes for lymphocyte transformation test.Histogeny was detected by HE staining technique,and T cell development was determined by immunohistochemistry.T lymphocyte proliferation and IL-2 inductive activity were examined by using MTT assay.The experiment was to aim at revealing T cell development and immune function of different age-old chicken immunized with Lasota vaccine.Results were as follows:This study investigated the tissue structure of thymus and spleen of different age-old chicken immunized Lasota vaccine by HE staining.Observation of the study discovered:thymus cortex and medulla of SPF control group chicken were divided brightly on 7^th post-hatching day.Along with increase of age,thymus lobule and corpuscles were increasing and became bigger,meanwhile medulla began to mix together.On the 96 day thymus medulla was connected together,formed the big sheet structure,and thymus corpuscles and epithelial cell was increasing simultaneously.On the 130^th day cortex began to become thin and adipose cell invaded to thymus substance,resulting that tymus strarted to degenerate.Compared with the control gounp, thymus of immunized gounp chickens had no obvious difference in the different age.Spleen white pulp and red pulp of SPF control group chicken were divided brightly on 7^th post-hatching day.Spleen node appeared at 14^th post-hatching day.With the increase of age,periarterial lymphoid sheath(PALS) and Spleen node were increasing gradually.Compared with the control gounp,the number and area of periarterial lymphoid sheath(PALS) and Spleen node in immunized gounp chickens was growing more and bigger significantly.The results indicate that thymus and spleen development of SPF control group chicken tended to mature and immune competence strengthened gradually with increase of age.Thymus development was not affected in the different age-old chicken vaccinated Lasota,nevertheless spleen organizational structure was changed, resulting in enhancementing organism immune function.Immunohistology and computer graphic analytical technique were combined to investigate the development processes of T lymphocytes and subpopulation of thymus and spleen at different age-old chickens immunized with Lasota vaccine.Observation of the study discovered:CD3⁺,CD4⁺,CD8⁺T lymphocytes in the thymus and spleen of SPF control group chicken presented to increasing tendency totally with the increase of age.Compared with control group chicken,differences on the numbers of CD3⁺,CD4⁺ and CD8⁺T cell in the thymus of immunized gounp chickens were not significant with the increase of age. CD3⁺ and CD4⁺T cell in the spleen of immunized gounp chickens were higher than control gounp chickens, however CD8⁺T cell were lower obviously(P< 0.05).The results indicated that the numbers of CD3⁺,CD4,CD8⁺T lymphocytes in the thymus and spleen of SPF control group chicken presented to increasing tendency totally,and reflected the age-related change.The numbers of T cell in the thymus of immunized gounp chickens immunized with lasota vaccine were not influenced obviously,however the numbers of T cell and subsets in the spleen were changed significantly.The change on the numbers of T cell in the spleen enhancemented cellular activation,antibody production and cytokine release.MTT assay was carried out on T lymphocyte proliferative response and IL-2 inductive activity of thymus and spleen of the different age-old chicken immunized with Lasota vaccine.Observation of the study discovered:T lymphocyte proliferative response and IL-2 inductive activity of thymus and spleen of SPF control group chickens began to exhibit the ability to respond to immune stimulation(ConA ) from 14 day-old, moreover,T lymphocyte proliferative response and IL-2 inductive activity have strengthened gradually with the increase of age.Ability to respond to immune stimulation(ConA) reached peak value at 56 day-old,then reduced and tended to stabilization at 94 day-old.Compared with control group chickens,cellular immune function has been enhanced after different age-old chickens were immunized with Lasota vaccine. Furthermore,T lymphocyte proliferative response and IL-2 inductive activity of thymus and spleen of the different age-old chickens immunized with Lasota vaccine were strengthened with the increase of age,and showed the age-related change.The results above disclosed comprehensively and firstly from tissue level,cellular level and molecular level were studied on the development of T lymphocytes and their immune function in the different age-old chickens immunized with Lasota vaccine.The results indicated that tissue occurrence of the thymus and development of T lymphocytes were not effected by Lasota vaccine in the different age-old chickens. However,tissue occurrence of the spleen,development of T lymphocytes and immune function can be enhancemented in the different age-old chickens immunized with Lasota vaccine,which reflected the age-related changes,in order to further discover the T cell mediated immunity mechanism caused by ND vaccine and then provide advantageous data.Moreover it can provide rationale for immunity at the right moment and disease prevention.