Immunohistochemical demonstration of Fc receptors of human lymph node cells using peroxidase-antiperoxidase (IgG).

Human lymph node cells, prepared from regional lymph nodes excised from four patients with gastric cancer, were incubated with peroxidase-antiperoxidase (IgG) (PAPIgG). After being washed, they were reacted with diaminobenzidine tetrahydrochloride in the presence of H2O2. Light microscopic examination revealed that a certain proportion of lymph node cells (18.2-32.2%) were labeled on their cell surface with brown-colored reaction products and that the labeled cells were composed of small lymphocytes. Electron microscopic examination demonstrated electron-dense irregular-shaped aggregates of reaction products on the cell surface of lymphocytes. Characterization experiments confirmed that the immune complexes of PAPIgG bound specifically with Fc receptors. PAPIgG, therefore, can be used as a specific indicator for Fc receptor of human lymph node cells.