Analysis of expression of MHC class I molecules and TAP genes in malignant human cell lines.

TAP proteins (transporters associated with antigen processing) take part in the transport of oligopeptides created in proteasomes from cytoplasm into endoplasmic reticulum. In the endoplasmic reticulum those oligopeptides are bound to MHC class I molecules and transported to the cell surface. TAP proteins consist of two subunits: TAP1 and TAP2. It has been previously shown that TAP protein expression can be decreased in malignant cells, followed by reduced protein expression or complete lack of MHC class I antigens on the cell surface. The aim of the study was to characterize of MHC class I protein expression and TAP mRNA synthesis in twenty human malignant tumor cell lines. MHC class I protein expression was examined by immunohistochemistry and flow cytometry. Expression of TAP genes was studied using RT-PCR and real-time PCR. All tested cell lines expressed MHC class I molecules. Flow cytometry showed different expression of MHC class I protein in tested cell lines. Molecular analysis revealed the presence of TAP1 and TAP2 gene transcripts in all cell lines examined. Quantitative real time PCR analysis showed differences of gene expression among cell lines tested

Flow cytometric analysis of CD55 and CD59 expression on blood cells in paroxysmal nocturnal haemoglobinuria

PNH is a rare clonal disorder of hematopoietic stem cells, therefore all blood cells lineages are involved. The main feature is an increased sensitivity of erythrocytes to complement-mediated cell lysis due to deficiency of membrane-bound GPI (glycosylphosphatidylinositol)-anchored proteins which normally function as inhibitors of reactive hemolysis. In the present study, we performed flow cytometric analysis using monoclonal antibodies against CD55 and CD59 for the detection of PNH-type clone in the blood of 50 patients (28 females and 22 males, age range 7-67 yrs). In one patient only we found a large population (95%) of granulocytes with decreased expression of both CD55 and CD59 molecules (type I PNH) and in two others with partial loss of CD55 expression (type II PNH). The expression was determined chiefly on granulocytes which in the control group showed reliable and high expression of CD55 and CD59

Analysis of expression of MHC class I molecules and TAP genes in malignant human cell lines.

TAP proteins (transporters associated with antigen processing) take part in the transport of oligopeptides created in proteasomes from cytoplasm into endoplasmic reticulum. In the endoplasmic reticulum those oligopeptides are bound to MHC class I molecules and transported to the cell surface. TAP proteins consist of two subunits: TAP1 and TAP2. It has been previously shown that TAP protein expression can be decreased in malignant cells, followed by reduced protein expression or complete lack of MHC class I antigens on the cell surface. The aim of the study was to characterize of MHC class I protein expression and TAP mRNA synthesis in twenty human malignant tumor cell lines. MHC class I protein expression was examined by immunohistochemistry and flow cytometry. Expression of TAP genes was studied using RT-PCR and real-time PCR. All tested cell lines expressed MHC class I molecules. Flow cytometry showed different expression of MHC class I protein in tested cell lines. Molecular analysis revealed the presence of TAP1 and TAP2 gene transcripts in all cell lines examined. Quantitative real time PCR analysis showed differences of gene expression among cell lines tested