A human Ia cytoplasmic determinant located on multiple forms of invariant chain (gamma, gamma 2, gamma 3).

Abstract

An antigenic determinant present in the cytoplasm, but not on the surface membrane of human Ia+ cells, is defined by a monoclonal antibody (VIC-Y1) and is shown by immunoprecipitation and by NEPHGE to be expressed by Ia oligomers. Immunoprecipitations of cellfree translates and of purified Ia subunits indicate that the VIC-Y1 determinant is located on the Ia gamma-(invariant) chain, as well as on two other related molecules, provisionally termed gamma 2 and gamma 3. Within our experimental conditions, the three forms of gamma-chains co-precipitate exclusively with Ia oligomers. As detected by VIC-Y1 and in the limits of our assays, gamma-chains could not be found at the cell surface; their tissue distribution, determined by cytoplasmic indirect immunofluorescence with VIC-Y1, closely resembles that of Ia antigens, with the possible exception of acute lymphatic leukemia cells (Ia+, gamma-chain-).

Expression of Class II MHC Antigens in the Intestinal Epithelium of Pediatric Celiac Disease

“…The few DR3-and DR7-negative patients are DR4-positive (25). Class II molecules, while expressed by the epithelium of the small intestine (26)(27)(28)(29)(30)(31)(32), are absent or rarely detectable in normal large bowel mucosa (32). These antigens, on the other hand, can be identified at this anatomical site during Chrohn's disease (33) and in normal mucosa adjacent to neoplastic tissue (34).…”