DR Expression on Vascular Endothelial Cells in Normal Human Kidney

Human I1LA-DR antigens are expressed on cytoplas mic membrane o f cells associated with immunological activity [IJ. Moreover, the HLA-DR expression can be induced on other cells which arc normally negative for HLA-DR molecules. Thus, the thyroid follicular cells bear these antigens when cultured with mitogens (21. The umbilical vein endothelial cells express HLA-DR when cultured with phytohemagglutinin (31 or co-cultured with activated T cells 1*4]. Hayry et al. (51 observed HLA-DR antigens on the dispersed kidney vascular endothelial cells. In addition, morphological studies on tissue sec tions suggest that renal vascular endothelium appears to express HLA-DR antigens (6-8). We have observed, us ing immunofluorescence (IF) microscopy and a nucleic acid counterstain with ethidium bromide(EB), that in the normal human kidney these antigens are localized on the vascular endothelium around cellular structures. We have used a mouse monoclonal antibody directed against a monomorphic determinant o f 11 LA-DR (Edu-I) described elsewhere [9. 10). Normal renal tissue from 2 biopsy and 9 necropsy specimens was tested for HLA-DR antigens by indirect IF technique. A nucleic acid stain with F.B was used for cellular localization. Tonsil sections were used as positive control. M ono clonal antibody to non-HLA-DR antigens (Cris-1) [9. II] and ascitic fluid, obtained intraperitoneally o f Balb/c NSA myeloma line were used as negative controls. A constant pattern of HLA-DR antigens was observed in all the specimens. Heavy II staining was identified in the renal interstitium and in the glomerular capillary walls. Moreover, bright staining was observed in the mesan gium. LB counterstaining showed HLA-DR antigens around endothelial cells in glomerularcapillaries (fig. la) and probably vascular endothelial cells in intertubular capillaries (fig. lb).