ANALYSIS OF CELLULAR IMMUNITY AGAINST TUBERCULOSIS IN MAN WITH SPECIAL REFERENCE TO TUBERCULOUS PLEURISY AND CYTOKINES

Abstract

Because of containing of numerous immunocompetent cells, tuberculous pleurisy is a good model for analysis of local cellular immunity.
When lymphocytes in pleural effusion were cocultured with purified protein derivative (PPD), they reacted to PPD and produced far more interleukin 2 (IL-2) and interferon -γ (IFN-γ) than did peripheral blood lymphocytes. Analysis using monoclonal anti body and complement revealed that at least the OKT 4⁺/OKT8^- T-cell subset is respon sible for the antigen-specific IFN-γ production in pleural fluid T lymphocytes.
Tuberculous pleural fluid itself had far higher levels of IL-2 and IFN-γ than malig nant pleural fluid. Therefore, it is indicated that activated T lymphocytes in tuberculous pleural fluid concern the production of lymphokines at the morbid site.
Treatment with IFN-γ resulted in an increased percentage of human alveolar macrohpages ingesting BCG and an increased number of ingested BCG in individual alveolar macrophage in patient with pulmonary tuberculosis. The IFN-γ treatment also showed increased killing activity of alveolar macrophages. Through these studies, IFN-γ is an essential cytokine which activates human alveolar macrophages and induces antimycobacterial activity.
In conclusion, we could elucidate from the study of tuberculous pleurisy that exudative sensitized pleural fluid T-lymphocytes play a major role in the defence of tuberculosis at the morbid site.