Abstract
The application of an avidin--biotin immunoperoxidase staining system was investigated for the characterization of mononuclear cells in cytocentrifuge and imprint preparations with monoclonal antibodies. The system was found to be very sensitive, permitting the use of high dilutions of monoclonal antibody. The system also permitted the study of single cell morphology. Its utilization should be complementary to the study of patterns of cellular proliferation in frozen section material. Furthermore, it may lend itself to automation for quantitative analysis of cell populations.