Characterization of a Second Normal Antigen that Cross-Reacts with CEA

Abstract

The recent discovery of an antigen present in normal tissues that cross-reacts with the carcinoembryonic antigen of gastrointestinal tumors (CEA) ³ was made in several laboratories (1, 2). This antigen received different names, including that of nonspecific cross-reacting antigen (NCA) given by von Kleist, Chavanel, and Burtin (2). A study of the perchlorosoluble antigens present on the stools of non-cancerous and cancerous patients (3) led us to identify another antigen that cross-reacts with CEA which later on was found in normal tissues. We propose to name it NCA 2. Materials and Methods. The different categories of samples of stools and meconium were described in another paper (3). These samples were extracted volume/volume by 1 M perchloric acid, then precipitated with ammonium sulfate at 100% saturation, dialyzed and lyophilized. These perchloric extracts, dissolved in deionized water, were precipitated by an equal volume of absolute ethanol.