The expression of MHC class I, TAP1/2, and LMP2/7 gene in human gastric cancer cell lines

Intracellular antigens are presented to CD8(+) T cells through major histoc ompatibility complex (MHC) class I molecule. For stable MHC class I express ion, several molecules as well as the MHC molecule itself have to express s imultaneously and function well. To determine a gene associated with MI-IC class I surface expression, the expressions of LMP2/7 and TAP1/2 including MHC I gene were analyzed in ten human gastric cancer cell lines, using RT-P CR and Northern blot analysis. Although LMP2, TAP1/2, and MWC class I gene expression were reduced in some cells, this was not significantly associate d with MHC class I surface expression. By comparison, the expression of LMP 7 was significantly reduced in three of ten cell lines, which also showed l ow levels of MHC class I surface expression, and increased in four of ten c ell lines, which also showed high levels of MI-IC class I surface expressio n. These results suggest that the level of MHC class I surface expression i s associated, in most cases, with the expression of the LMP7 gene regardles s of the LMP2, TAP1, TAP2, or MHC class I genes.