Expression of C II TA gene in five human malignant hematological cell lines and its significance

Abstract

The role of MHC class II transactivator (C II TA) in constitutive or IFN-γ inducible expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and C II TA protein was detected by Western blot, immunohistochemistry and flow cytometry. The expression of C II TA gene was determined by RT-PCR. The capability of peripheral blood T cell reaction stimulated by tumor cells was monitored by mixed lymphocyte reaction. It was found that the HLA II-positive tumor cells expressed the C II TA quite well, and the expression of HLA I + II was increased in the tumor cells with constitutive or inducible expression of C II TA after induced by IFN-γ. The tumor cells which did not express C II TA after induced by IFN-γ were not response to the expression of HLA II promoted by IFN-γ. It suggests a correlation between the inability of some malignant hematological cell lines in response to IFN-γ for HLA expression and the deficiency in the inducible expression of C II TA, indicating C II TA might take part in the regulation of HLA I+II expression in the tumor cells, which might play an important role in tumor immunologic escape.

Keywords

MHC class II transactivator / antigen, HLA / IFN-γ / tumor cells

References

[1] AichunL, MasuhiroT, KenT, et al. . Regulation of the expression of MHC class I and II by class II transactivator (C II TA) in hematopoietic cells. Hematol Oncol, 1999, 17149-149

[2] GarridoF, CabreraT, ConchaA, et al. . Natural history of HLA expression during tumor development. Immunol Today, 1993, 41491-491

[3] HollingT M, van Der StoepN, QuintenE, et al. . Activated human T cells accomplish MHC class II expression through T cell-specific occupation of class II transactivator promoter III. J Immunol, 2002, 168(2): 763-763

[4] WaldburgerJ M, SuterT, FontanaA, et al. . Selective abrogation of major histocompatibility complex class II expression on extrahematopoietic cells in mice lacking promoter IV of the class II transactivator gene. J Exp Med, 2001, 194(4): 393-393

[5] MartenA, ZiskeC, SchottkerB, et al. . Transfection of dendritic cells (DCs) with the C II TA gene: increase in immunostimulatory activity of DCs. Cancer Gene Ther, 2001, 8(3): 211-211