HLA‐A, B, C; ‐DR; ‐MT, ‐MB, and SB antigens on unstimulated human endothelial cells

Abstract

Since major histocompatibility complex (MHC) antigens of class II play an important role in organ transplantation, we attempted to demonstrate their expression on endothelial cells which are abundant in transplants with vascular blood supply. Our analysis was performed with monomorphic and polymorphic monoclonal antibodies employing a microscopic immunofluorescence assay and flow cytometry on unstimulated endothelial cells isolated from umbilical cord veins. No evidence was found for the presence of HLA‐DR antigens and determinants associated with MT, MB and SB. MHC class I antigens exhibited reduced expression. These findings were confirmed in respect to alloantigens by the use of conventional cytotoxic tissue typing antisera. MB and SB antigens were present on most cord B lymphocytes, but could only be demonstrated on a subpopulation of monocytes exhibiting a lower antigen density at the cell surface. MT and DR antigens were found on most cord monocytes and B lymphocytes.

Two sequence dimorphisms of DPB1 define the immunodominant serologic epitopes of HLA-DP

“…In regard to the clinical importance of anti-DP antibodies, we must bear in mind that the relatively lower level of expression of DP molecules on the cell surface has been known from the beginning when DP molecules were still called "SB" [12,13]; and that, because of this lower level of expression, the clinical effect of antigenantibody reactivity is not as striking and prominent as in the case of antibodies specific for antigens in other loci.…”