Screening for Xenoantigenic Determinants Formed by Sialyltransferases

Abstract

In this study, we established pig kidney (PK15) cell lines which are transfected by human sialyltransferases including human a-2, 3-sialyltransferase (hST3Gal II) and human α-2, 6- sialyltransferase (hST6Gal I, hST6GalNAc IV). The transfected cells were screened by Western blot analysis and Lectin blot analysis. The cytotoxicity and xenoreactivity of the PK 15 cell lines were examined by performing the LDH cytotoxicity assay and FACS analysis. From LDH cytotoxicity assay, cytotoxicity to human serum significantly was increased in hST3Gal II and hST6GalNAc IV transfected PK 15 cells as compared to the control. Moreover, from the FACS analysis, binding capacities of human IgG to ST3Gal II- and ST6GalNAc IV-transfected cells were significantly increased, compared with control cells. However, dramatic changes were not observed in IgM binding assay, in comparison with binding assay of IgG. Therefore, our results suggest that alteration of glycosylation-pattern by sialyltransferases including hST3Gal II and hST6GalNAc IV gene results in increase of human serum-mediated cytotoxicity to pig kidney cells and the increased susceptibilities to cytotoxicity may result from the increased human IgG binding capacity to these cells rather than human IgM.