Abstract: Abstract: Objective Detect the role of P.yoelii plasmodium derived macrophage migration inhibitory factor (PyMIF) recombination protein on the phenotype and function of bone marrow dendritic cells (BM-DC). Methods : BM-DC induced from bone marrow precursors were treated with PyMIF or MmMIF，then cell surface molecular such as TLR2、TLR4、CD80、CD86、CD40、MHCII were detected by flow cytometry and IL-12、IL-10 were analyzed by ELISA. PyMIF or MmMIF treated BM-DC were first stimulated by LPS，then co-cultured with CD4+T or CD8+T cells, CD69 and IL-2 were detected as previously described to indentify the activity of T cells. What’s more, the tytotoxic action of CD8+T was also measured. Results: PyMIF decreased the TLR4 expression of BM-DC，but had neither effect on TLR2、CD80、CD86、CD40 and MHCII expression, nor influence on IL12、IL-10 secreting. What is more, PyMIF down-regulated CD69 expression of CD8+T through BM-DC, and could not influence CD69 expression and IL-2 secrecting of CD4+T and IL-2 secrecting of CD8+T cells through BM-DC. Conclusion：PyMIF could down-regulated TLR4 expression of BM-DC to prevent being attacked by immune system, so as to survive in the organism.

Key words: PyMIF, BM-DC , TLR4, CD69