T-cell immune tolerance of HLA haploidentical donor induced by CTLA4Ig-modified bone marrow stromal cells

Wang Ji-gang; Zhou Fan; Liu Yan-qin; Bai Ying; Liu Jing-hua; Zhang Hai-ting; Li Min-yan

doi:10.3969/j.issn.2095-4344.2015.01.003

Abstract：BACKGROUND:CTLA-4Ig as a tolerance-induction agent is a potential strategy in graft-versus-host disease prevention. OBJECTIVE:To investigate the efficacy of CTLA4Ig-gene-modified bone marrow stromal cels mediated by adenovirus to induce T-cel tolerance of haploidentical donors. METHODS: The bone marrow stromal cels isolated culture from the bone marrow of HLA haploidentical donors were transfected by recombinant adenovirus encoding CTLA4IgcDNA (AdCTLA4Ig) at a multiplicity of infection=50 for 72 hours. The expression rate and the location of CTLA4Ig in the transfected cels were detected by fluorescence microscope after immunofluorescence staining. CTLA4Ig-modified bone marrow stromal cels (2×104, 4×104and 8×104) were respectively co-cultured with 105 T cels from the peripheral blood of HLA haploidentical donors and 105 peripheral blood mononuclear cels from recipients. The proliferative inhibition rate was determined by MTT assay, and the level of interleukin-2 in the supernatant was detected by ELISA. The bone marrow mononuclear cels (1×105/wel) were co-cultured with CTLA4Ig-modified bone marrow stromal cel layers constructed in 6-wel plates. The number of bone marrow mononuclear cels and colony-forming unit-granulocyte macrophages were calculated after 5-day culture. RESULTS AND CONCLUSION: The expression rate of CTLA4Ig at the multiplicity of infection=50 was as high as 85%, and the immunofluorescence signals of CTLA4Ig were distributed unevenly in the cytoplasm. The inhibition rates of 2×104, 4×104, and 8×104 CTLA4Ig-modified bone marrow stromal cels on proliferation of T cels were higher than that of untransfected cels. The levels of interluekin-2 in the corresponding cel groups were significantly lower than that in the untransfected cels (P < 0.05). At 5 days of culture, there was no significant difference in the number of bone marrow mononuclear cels and colony-forming unit-granulocyte macrophages between the transfected and untransfected cel groups (P > 0.05). These findings indicate that CTLA4Ig-modified bone marrow stromal cels mediated by adenovirus can induce immune tolerance of T-lymphocyte from HLA haploidentical donors in vitro.