[The immunology of tuberculosis]

An introductory overview on the present state and future prospect of the immunology of tuberculosis is presented with the following six chapters. 1. Contribution of tuberculosis immunologists to the modern immunology. When one reminds Koch's phenomenon, Freund's adjuvant, and the findings or new ideas of, for instance, cell-mediated transfer of tuberculin allergy, test of MIF which was first described as "lymphokines", effector macrophages activated with immune lymphocytes against mycobacterial infection, MHC-restriction for presenting tuberculin-antigen from macrophages to T cells, everyone may agree with saying that the tuberculosis immunology contributed greatly to the opening and development of modern immunology. 2. Central dogma of tuberculosis immunology. Tuberculosis immunology possesses a central dogma : infection of tubercle bacilli----phagocytosis----antigen presentation----expansion of specific T cell clone----production of lymphokines----macrophage activation----killing of the bacilli. Recent knowledges from modern immunology have clarified many things in or around this immunological process. However, there remain many important questions. In the following chapters and subtitles, what have been clarified and what are still unsolved will be described. 3. Induction of tuberculosis immunity. (1) Mechanisms of phagocytosis with macrophages, and natural resistance. (2) Antigen presentation and sensitized T cells. 4. Expression of tuberculosis immunity. (1) Lymphokines. (2) Activation of macrophages. (3) Immune suppression. 5. Special characters of tubercle bacilli in relation to the host response. Biochemistry of cellular components of tubercle bacilli and their biological activities have been reported by many investigators already in this journal. Therefore, the following items only are discussed here. (1) Mycobacterial proteins produced by gene-technology. (2) Adjuvant active derivatives of MDP. (3) DNA from BCG and its biological activities. (4) Difference of immunity induced by viable and dead bacilli. About (4), possible mechanisms to explain the difference are discussed, with emphasis of both MPB70 protein as an antigenic metabolite released from viable bacilli and the heat-shock mycobacterial proteins. 6. Unsolved problems in tuberculosis immunology. (1) Mechanisms of endogenous reactivation. (2) Development of new vaccine. (3) Others. In addition to the practical problems on tuberculin diagnosis and BCG vaccination, problems to be solved in and around the central dogma are discussed. Some examples of these problems are illustrated in Fig.7 in English.