Immunity in tuberculosis

Abstract

Many of the factors involved in the production and mechanism of immunity to tuberculosis are reviewed. Results of experimental work in animals are given in some detail and where possible are correlated with observations in man. The results differ somewhat in detail between various species, but in general a wide range of mycobacteria will protect against tuberculous infection, though the degree of protection varies, and at best is never as good as that seen in certain other infections, e.g. diphtheria or smallpox. Immunity develops within a week or so after vaccination and gradually increases in intensity during the first two months. The duration of immunity seems to vary depending on the vaccine, route of vaccination used, and possibly species, though in man at least it seems to last for more than six years. The relationship between allergy and immunity is discussed and evidence is given that these are independent phenomena and that either can exist in the absence of the other. Clinically the importance of this is that failure to convert to Old Tuberculin after BCG vaccination need not mean that good protection has not been developed, and in fact it is demonstrated that humans can show good protection in the absence of hypersensitivity. The cellular and humoral factors involved in immunity to tuberculosis are discussed, as are also the effects of oxygen tension, local organic acid concentration, and the effect of sex. © 1960 Baillière, Tindall & Cox, Ltd.