Production, analysis, and characterization of reference materials for prostate-specific antigen.

Objective: To produce a set of three reference materials that mimic sera from patients with prostate disorders in the prostate-specific antigen (PSA) concentration range important for clinical screening for prostate cancer (approximately 0.5, approximately 4.0, and approximately 10.

Expression of class II molecules on intestinal epithelial cells in humans. Differences between normal and inflammatory bowel disease.

Expression of class II antigens on human intestinal epithelial cells was assessed using a sensitive avidinbiotin-peroxidase technique. HLA-DR was present predominantly in the normal small bowel with diminished but evident expression in the colon. HLA-DP staining was less prominent, and HLA-DQ was absent.