Differentiated vs. undifferentiated promyelocytic cell lines (HL-60 and KG-1) and Neutrophiles

We identify the tetraspanin CD82 as the recognition site for xenogeneic endothelial cells independently of Gala1,3-gal structures. We demonstrate that in contrast to undifferentiated cells, differentiated promyelocytic cell lines (HL-60, THP-1 and KG-1) are capable of recognizing xenogeneic porcine endothelial cells in a calcium-dependent manner. We used serial analysis of gene expression (SAGE) to identify the differentially expressed transcripts in these cell lines. Interrogation of these transcripts revealed a number of differentially expressed genes that include the Gala1,3-gal-independent recognition moiety(s). Comparing these SAGE transcripts with those expressed in resting human naive neutrophils identified the tetraspanin CD82 as the most likely candidate responsible for xenogeneic recognition. Blocking antibodies to CD82 in human naive neutrophils inhibited the calcium response and abolished the subsequent Reactive Oxygen Metabolite (ROM) production evoked by the xenogeneic encounter of either Gala1,3-gal knockout or wild-type porcine aortic endothelial cells. Our data identify CD82 on innate immune cells as the major recognition moiety of the xenogeneic endothelium, independently of Gala1,3-gal-structures and open new avenues of intervention to making xenotransplantation a clinical reality. We used serial analysis of gene expression (SAGE) to identify the differentially expressed transcripts in promyelocytic cell lines (HL-60, THP-1 and KG-1) upon differentiation. We looked for genes common to the differentiation pathway in these cell lines but absent from the control naiive neutrophiles.