IDENTIFICATION AND QUANTIFICATION OF COMPLEMENT REGULATOR CD46 ON NORMAL HUMAN TISSUES

CD46 is a cell-surface regulatory molecule that prevents lysis of auto logous human cells by activated complement. It has been well character ized on leucocytes, reproductive cells and various cultured cell lines and is considered to be ubiquitously expressed. We now extend these a nalyses and describe CD46 in a variety of different human tissues. Str ong expression was observed by immunohistology on epithelial cells lin ing exocrine ducts and glands, such as salivary gland and pancreas and on kidney tubules and glomerular epithelium. Quantitative tissue expr ession was measured by radioimmunoassay and confirmed histological obs ervations. Thus, CD46 is highly expressed on cells in contact with ext racellular fluids thought not to contain large quantities of complemen t but which may still be subjected to complement attack thereby necess itating the presence of complement regulators to prevent non-specific destruction of cells.