Cytokine expression and production by tonsillar lymphocytes

Expression of various cytokines in the tonsillar compartments, and in vitro cytokine production and cytokine mRNA expression by tonsillar lymphocytes (TL), were investigated. In immunohistological analysis, a wide variety of cytokines such as interleukin (IL)-1 beta, IL-2, IL-4, IL-5, IL-10 was expressed intensively in the lymphoepithelial symbiosis (LES). A certain number of cells producing IL-6, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha was distributed not only in the LES but also in the extrafollicular area. A significant amount of IL-6, IFN-gamma, and TNF-alpha was detected by enzyme-linked immunosorbent assay in the culture supernatants of TL cultured with streptococcal antigen, even without any mitogens. Furthermore, mRNA of IL-6, IFN-gamma, and TNF-alpha was determined by reverse transcription polymerase chain reaction on the TL freshly isolated and with streptococcal stimulated antigen, whereas, production of IL-1 alpha, IL-4, and IL-5, and expression of their mRNA were not found on TL with or without streptococcal stimulation. These data indicate that tonsils are highly active immunological organs containing a wide variety of cytokine-producing cells, and suggest that IFN-gamma, TNF-alpha, and IL-6 may play an important role on the immune response to bacteria in the tonsil.