Specific binding of HLA-B44 to human macrophage MHC receptor 1 on monocytes

Down-regulated expression of monocyte/macrophage major histocompatibility complex receptors in human and mouse monocytes by expression of their ligands

“…Humans are typically outbred mammals, and a fetus expresses paternal MHC class I molecules in addition to maternal molecules. In addition, an earlier study showed that none of 16 healthy volunteers express HLA‐B44, a ligand of MMR1, whereas MMR1 mRNA is expressed only in PBMCs from three of 16 volunteers , implying down‐regulation of MMR1 expression by some linkage among human MMR genes, as described above in the mouse (Fig. ).…”

“…HLA‐A11,24HLA‐B51,52) express both MMR1 and MMR2 mRNAs, whereas those from another volunteer (i.e. A24,33B52,61) express none . In fact, PE‐labelled HLA‐B62 pentamers bound to PBMCs from the MMR2 mRNA + , but not those from the MMR2 mRNA – , volunteer within 1 min of incubation (Fig.…”

“…non‐ligand), but not H‐2D d (i.e. ligand), inbred mice . H‐2K d (or H‐2D d ) transgene into C57BL/6 (H‐2D b K b ) mice down‐regulated not only MMR2 (or MMR1) but also MMR1 (or MMR2) expression (Fig.…”

“…). In fact, PBMCs from four of 16 volunteers expressed HLA‐B62 molecules (a ligand for MMR2), whereas PBMCs from these 16 volunteers expressed MMR2 with a frequency of eight of 12 volunteers ; none of the PBMCs from the 16 volunteers expressed HLA‐B44 molecules (a ligand for MMR1), whereas PBMCs from these 16 volunteers expressed MMR1 with a frequency of three of 16 . Furthermore, MMR2 knock‐out mice failed to reject skin grafts from H‐2D d ‐ or H‐2D d K d ‐transgenic mice as well as from H‐2K d ‐transgenic mice, but they rejected skin grafts from mice expressing H‐2I d , minor H d or third‐party MHC .…”

“…non‐ligand), but not those from H‐2D d (or H‐2K d ; i.e. ligand), inbred mice ; and MMR1 –/– and/or MMR2 –/– C57BL/6 mice failed to reject H‐2D d ‐ and/or H‐2K d ‐transgenic mouse skin grafts onto C57BL/6 mice . Moreover, we isolated cDNAs encoding the human homologues of mouse MMR1 and MMR2 and found their expression on at least some of the peripheral blood mononuclear cells (PBMCs) or monocytes, but not on granulocytes or lymphocytes .…”