Allorecognition And T Cell Activation

Aim: The purpose of this study is to establish a fast and precision evaluating system on alto-recognition for further study on mechanism by which allograft is rejected. Methods: The models for transplant antigen recognition used in this study are as follow. Mixed lymphocyte culture (MLC) is used as the model for studying in vitro alto-recognition. Transplant of myocardio-tissue into mouse ear subcutaneously is used as a model for local observation of graft. Transplant of myocardio-tissue into mouse forearm subcutaneously is used as a model for investigation of direct recognition of alto-antigen. And, abdomino-transplant of isolated hepatocytes is used as a model for investigation of both direct and indirect recognition of alto-antigen. The main parameters include expression of surface molecules (for example CD69) and cytokines during T cell activation. The T cell surface molecules and intracellular cytokines were marked with fluorescence conjugated antibodies, and detected by flow cytometry. Results: In the mixed lymphocyte culture system, the percentages of CD69 and CD25 by the responder cells during 48 hour culture were significantly higher than those from the control group, respectively 20.65 .0 vs.7.16 .2I,40.54 1.87 vs.16.91 .93. While the percentages of IFN-y by the responder T cells were significantly higher than those from the control group, respectively 18.65 .00 vs. 1.20 0.16. As compared with isograft, there is more significant evidence of immunological inflammation and vascular dilatation in the local area in the mouse with myocardio-tissue graft in ear. Compared to isograft, the expression rates of CD69 by the CD4 T cell and CD8 T cell from the drainage lymphnode in the mouse with allo-myocardio-graft were significantly higher. Treatment with Freund's complete adjuvant during transplantation enhanced CD69 expression by the T cells stimulated by alto-antigens. Abdomino-transplant of isolated hepatocytes resulted in an increase of expression of CD69 by T cells from the mesenteric lymph nodes, which could be inhibited by cyclosporin A. No selective usage of TCR Vf3 segment was found in T cell population from the mcsenteric lymph nodes of the mouse with abdomino-transplant of isolated allo-hepatocytes when the detection was performed with 17 anti-TCR VJ3 antibodies. Conclusion: Our results showed that we have created a new method of MLC. Compared to the traditional method, our method has the advantage of no isotope need, time saving, no pretreatment (irradiation) of stimulator cells, understanding of alto-recognition in single cell level, reflection of the mode of alto-reaction and capability of understanding of alto-recognition by different T cell subsets and combination of different MHC alleles. Myocardio-tissue transplant into mouse ear is a good model for local observation of immune response. Tissue transplant into forearm or abdominal cavity and analysis of activation of T cell from the drainage lymph node was an useful model for evaluating effect of drugs or other immune interventional factors.