Study On The Immune Responses Of Goats Infected With Mycoplasma Capricolum Subsp. Capripeumoniae

Contagious caprine pleuropneumonia(CCPP),also known as "rotten lung disease",is a highly contagious and seriously harmful infectious disease in goats.The earliest record of the disease was reported by Hutcheon in 1889,but it is now prevalent in our country and other goat-raising countries in the Middle East,West Asia and Africa.The clinical manifestations of CCPP are mostly fever,dyspnea,pleural pneumonia,and pleurisy,which cause significant economic losses and seriously affect the development of my country's sheep industry.The pathogen of CCPP is Mycoplasma capricolum subsp.capripeumoniae(Mccp).It is important to understand the characteristics of the body's immune response after Mccp infection and to design and develop new CCPP vaccines.The body's immune response to Mycoplasma infection is not limited to humoral immunity,but cellular immunity is also an important aspect.However,there is little research data on the immune response characteristics of Mccp infection in goats at home and abroad.This study draws on the research progress of other mycoplasmas,using Mccp infected goats as the research object,using ELISA,flow cytometry and other methods to determine the serum antibody and cytokine levels,PBMC proliferation,apoptosis and T cell subsets CD4+/CD8+changes.Five healthy goats were infected with Mccp in the experimental condition.On the Ost,1st,11th,18th,25th and 32th days after infection,whole blood samples were used to separate serum and PBMC,Mccp antibody levels in serum at different times was detected by indirect ELISA method established by our laboratory Antibody levels in serum at different times after the test;detection of changes in cytokines IL-6,IL-10,IL-4,IL-1?,and INF-? in serum was detected by commercial kits;detection of Mccp stimulation was performed by CCK-8 method after the proliferation of PBMC cells;flow cytometry was used to detect the apoptosis of PBMC cells and T cell subsets;after detection of serum antibody levels,cytokines,PBMC cell proliferation and apoptosis,and T cell subsets,the immune responses of goats infected with Mccp were analyzed,The study may lay a certain foundation for future understanding the immune response of Mccp infection.The results showed that antibodies in the serum of goats became positive after 11 days of infection,suggesting Mccp infection could cause an acute humoral immune response;the serum levels of IL-1?,IL-4,IL-10,and IFN-y all increased to different degrees after 11 day of infection,indicating that Mccp infection caused inflammatory response;cell proliferation experiments found that live or inactivated Mccp stimulated PBMC can cause cell proliferation;flow cytometry was used to detect the effect of Mccp infection on apoptosis of PBMC cells,and it was found that both live Mccp and inactivated bacteria can cause apoptosis of PBMC cells(p<0.001),but different goats exist big differences.The results of T cell subpopulations indicated that the CD4+ and CD8+ levels in most goats are higher than that of the control group before and after infection and in most Mccp stimulated groups.CD4/CD8 ratio is lower after infection than before infection(p<0.001),The results showed that helper T cells were dominant after infection.The results suggest that Mccp infection causes strong humoral and cellular immunity.