Abstract: [Abstract]Objective: To construct the mouse bone marrow hematopoietic stem cells with chimeric MHC-I gene. To explore the mechanism of it inducing T lymphocyte response to allogeneic dendritic cells. Methods: mouse bone marrow hematopoietic stem cells were collected with the lymphocyte separation medium (ficoll), by density gradient separation. Identified hematopoietic stem cell (HSC) were infected by the constructed lentiviral vectors. After infection, the molecular chimerism was successfully constructed. The ability of molecular chimerism reduce T lymphocyte response to allogeneic dendritic cells was observed through MLC. Results: Using ficoll, the Balb/C mouse bone marrow HSCs were successfully separated. The rate of CD34+ cells was up to (34.64±2.76)%. 3 days after lentivirus infection, H2-K1 gene expression at mRNA level in Balb/C mouse hematopoietic stem cells increased 657-fold than that of the non-infect group, increased 666-fold than that of the control group. The H2-K1 expression at mRNA level between control group and non-infect group had no significant difference (P>0.05). Flow cytometry analysis indicated that H-2Kd expressed in 98.17% cells. The result of MLC demonstrates that the index of stimulation to T lymphocyte significantly decrease. (P<0.01) Conclusion: The lentiviral vector carrying C57 mice`s MHC-I gene H2-K1 was successfully constructed. Balb/C mouse bone marrow hematopoietic stem cells can be successfully infected by the lentiviral vector. After infection, a stable and long-term expression of H2-K1 was achieved and H-2Kb protein was expressed. The molecular chimerism could reduce T lymphocyte response to allogeneic dendritic cells.

Key words: MHC-I gene, bone marrow hematopoietic stem cell, lentiviral vectors, immune tolerance