Overexpression of TAP1 up-regulates HLA-Ι in human glioma U251 cells

AIM：To investigate the relationship between the overexpression of transporter associated with antigen processing 1 (TAP1) and the human leukocyte antigen I (HLA-I).METHODS：The full length of TAP1 gene was obtained from the cDNA library. The lentiviral vector pSIN-EF2-IRES-GFP-puro was digested by BamH I and EcoR I, and the full length of TAP1 gene was inserted into the vector by T4 DNA ligase. Subsequently, the recombinant plasmid was transformed into Escherichia coli DH5α cells and the correct transformant was selected. The recombinant plasmid and the Lenti-X HTX packaging mixture were co-transfected into 293T cells, and the virus particle was acquired. Human glioma U251 cells were transfected with the lentivirus. The expression of TAP1 and HLA-I was determined by real-time fluorescence quantitative PCR, Western blotting and flow cytometric analysis.RESULTS：TAP1 gene was successfully transfected into the U251 cells and stably expressed in the cell line. The expression of TAP1 in U251 cells at mRNA and protein levels increased by (8.73±1.07) and (11.71±0.83) folds, respectively. As a result, the mRNA expression of HLA-A, HLA-B, HLA-C (heavy chain) and β2-microglobulin (light chain) was up-regulated by (3.51±0.36), (4.78±0.85), (2.94±0.28) and (3.23±0.24) folds, respectively. The protein expression of HLA-I also increased to (3.14±0.53) fold. The surface expression of HLA-I on the U251 cells transfected with TAP1 gene was largely enhanced as well.CONCLUSION：Overexpression of TAP1 up-regulates the expression of HLA-I. TAP1 plays an important role in HLA-I processing pathway.