ABSTRACT
Subepithelial and intraepithelial lymphocytes of human adenoids and tonsils were characterized and directly compared to determine the potential contribution of these tissues to mucosal and systemic immune responses. The distribution of T and B cell subsets, cytokine patterns, and antibody (Ab) isotype profiles were similar for adenoids and tonsils. Both tissues contained predominantly B cells ( approximately 65%), approximately 5% macrophages, and 30% CD3(+) T cells. The T cells were primarily of the CD4(+) subset ( approximately 80%). Tonsillar intraepithelial lymphocytes were also enriched in B cells. The analysis of dispersed cells revealed a higher frequency of cells secreting IgG than IgA and the predominant Ig subclass profiles were IgG1 > IgG3 and IgA1 > IgA2, respectively. In situ analysis also revealed higher numbers of IgG- than IgA-positive cells. These IgG-positive cells were present in the epithelium and in the subepithelial zones of both tonsils and adenoids. Mitogen-triggered T cells from tonsils and adenoids produced both Th1- and Th2-type cytokines, clearly exhibiting their pluripotentiality for support of cell-mediated and Ab responses. Interestingly, antigen-specific T cells produced interferon-gamma and lower levels of interleukin-5. These results suggest that adenoids and tonsils of the nasopharyngeal-associated lymphoreticular tissues represent a distinct component of the mucosal-associated lymphoreticular tissues with features of both systemic and mucosal compartments.
Subject(s)
Adenoids/physiology , B-Lymphocytes/physiology , Nasopharynx/physiology , Palatine Tonsil/physiology , T-Lymphocytes/physiology , Adenoids/cytology , Adenoids/immunology , Adolescent , Antibodies/analysis , Antibody Formation , Antigens/immunology , B-Lymphocytes/cytology , B-Lymphocytes/immunology , Cell Division/drug effects , Cell Division/physiology , Child , Cytokines/biosynthesis , Epithelial Cells/physiology , Humans , Immunoglobulin A/analysis , Immunoglobulin G/analysis , Immunoglobulin Isotypes/analysis , Mitogens/pharmacology , Monocytes/cytology , Palatine Tonsil/cytology , Palatine Tonsil/immunology , Phytohemagglutinins/pharmacology , T-Lymphocyte Subsets/cytology , T-Lymphocytes/immunologyABSTRACT
Epithelial cells of adenoid origin were grown in tissue culture to examine viral replication in cells that are the primary target of many human pathogens. These cells remained highly differentiated, with subpopulations of cells which retained active ciliary motility and others which demonstrated specialized secretory functions. The epithelial cells were permissive for growth of influenza A virus. Primary respiratory epithelial cells provide a model system for examining virulence, cell tropism, and receptors which replicate in the nasopharynx.