颗粒抗原交叉呈递机制的初步研究

Primary study on the mechanism of particle antigen cross presentation

目的以噬菌体颗粒抗原为模式抗原,研究其交叉呈递的可能机制。方法将该抗原与巨噬细胞共培养后,采用流式细胞技术和共聚焦显微镜,进行了多肽-MHC-Ⅰ类分子复合物形成的动力学研究。进而,采用流式细胞技术研究了不同蛋白酶体抑制剂以及TAP对噬菌体颗粒抗原交叉呈递的影响。结果巨噬细胞负载重组噬菌体颗粒pC89h isOVA或pC89h isHa后,细胞质MHC-Ⅰ类分子-肽复合物很快形成(约5 h);并且该颗粒抗原的交叉呈递以TAP(transport assoc iated prote in,TAP)依赖的方式进行。MG132,lactacystin以及NH4C l可以显著抑制胞内MHC-Ⅰ类分子-肽复合物的形成,而leupeptin或bestatin处理细胞却不影响该颗粒抗原的交叉呈递。结论噬菌体颗粒抗原交叉呈递是以TAP依赖的方式进行,并对多种蛋白酶体抑制剂敏感。

Objective Phage particle antigens were used as a model antigen to investigate the potential mechanism of cross presentation. Methods The MHC- Ⅰ -peptide complexes formation was analyzed by FACS and cofocus technology after macrophage cells were cocuhured with recombinant phage particles. Furthermore, the effect of proteasome inhibitors and TAP on particle antigens cross presentation was investigated by FACS analysis. Result The cytoplasmic MHC- Ⅰ-peptide complexes were markedly increased and reached a plateau at about 5 h after macrophage cells were cocultured with pC89hisOVA or pC89hisHa and the cross presentation of phage particles is TAP dependent. It was observed that MG132, lactacystin, and NH4Cl markedly inhibited the formation of MHC- Ⅰ -peptide complexes. However, leupeptin or bestatin treatment did not affect the cross presentation of phage particles. Conclusion Cross presentation of phage particles is TAP dependent and sensitive to proteasome inhibitors and NH4Cl.