HT7, Neurothelin, Basigin, gp42 and OX-47--many names for one developmentally regulated immuno-globulin-like surface glycoprotein on blood-brain barrier endothelium, epithelial tissue barriers and neurons.

The antigens HT7 and Neurothelin were recently described as inducible membrane glycoproteins on chick blood-brain barrier endothelium. Our results demonstrate that the Neurothelin antibody 1W5 does recognize the isolated HT7 protein as well as the HT7 protein expressed by COS-1 cells transfected with the HT7 cDNA. Therefore, the HT7 and Neurothelin epitopes can be found on an unique glycoprotein. By low stringency hybridization we have isolated the murine cDNA clone encoding the homologous murine protein. The nucleotide sequence of the open reading frame is identical to that of the cDNA clones encoding the gp42 protein and the Basigin antigen expressed in F9 cells and in the early mouse embryo. The murine amino acid sequence shows 94% identity with the rat OX-47 membrane glycoprotein which was shown to be expressed in blood-brain barrier endothelium and several epithelial cell layers. These results demonstrate that HT7, Neurothelin, gp42, Basigin and OX-47 are different names for probably the same glycoprotein in different species.