Nasopharyngeal Tonsil's Provision of the Surface Secretions with Immunocytes,a Property Additional to Antigen Processing

Abstract

As we recently found that IgA, IgM, and IgG are produced and secreted by immunocytes present in nasopharyngeal secretions, we tested the hypothesis that B- and T-lymphocytes in the surface secretions are derived from the nasopharyngeal tonsil in an active process. By immunohistochemistry, we found that numerous B- and T-lymphocytes were often accumulated in restricted areas in the epithelium, and some of these cells were demonstrated just beneath the epithelial surface or could be observed protruding into the lumen. A portion of these cells were Ki-67⁺, indicating clonal expansion and/or immunoglobulin class switching. Analyses of the surface secretions by immunocytochemistry also demonstrated B- and T-lymphocytes, as well as Ki-67⁺ cells — a finding that indicates that immunologically active cells are transported into the surface secretions. The results imply that there is a substantial migration from the nasopharyngeal tonsil of immunologically active cells into the surface secretions.