Macrophage migration inhibitory activity of mycobacterial growth inhibitory factor and the effect of a number of factors on mycobacterial growth inhibitory factor activity

Endobronchial tuberculosis presenting as asthma

Clinical deterioration with features suggestive of asthma was seen in three patients following two to six months of drug therapy of primary tuberculosis. There was a poor clinical response to administered bronchodilators. Bronchoscopy in all three revealed culture-negative mycobacterial caseating granulomas. Corticosteroid therapy resulted in good clinical response, with resolution of the asthmatic symptoms and improvement in the expiratory flow rates. In our opinion these patients are clinically compatible with a hypersensitivity response to mycobacteria following antituberculosis therapy and release of tuberculosis antigens. Corticosteroid therapy is appropriate in this form of tuberculous disease.

Suppression of tuberculoimmunity in mice by Evans blue dye

Evans blue dye, which acts as an adjuvant in mice to promote induction of cell-mediated immunity, was found earlier to apparently act contrarily and decrease tuberculoimmunity. This phenomenon was investigated here in a long-term experiment examining the persistence of the suppressed immunity. Systemic suppression after injection of only 1 mg of dye was confirmed and was found to last for more than 2 weeks but less than 11 weeks. Localized evidence for dye-caused depression of tuberculoimmunity also was seen by the development in dye-injected mice immunized with emulsified whole bacilli of caseating tubercles at sites of pulmonary infection, a very rare type of pathology for tuberculosis in mice. The experiment, in addition, detected an aging-related decline in mice of resistance to tuberculosis evident by shortened survival, enlarged pulmonary tubercles, and increased susceptibility to systemic tuberculin reaction.

Cellular immunity of mice to Leishmania donovani in vitro: lymphokine-mediated killing of intracellular parasites in macrophages

Leishmania donovani, an intracellular protozoan, causes kala-azar by parasitizing the macrophages of its mammalian host. Outbred NCS and CD-1 mice develop immunity to this parasite. This immunity was demonstrable when supernatant fluids from cultured splenic lymphocytes were added to infected macrophages. Only the lymphokine preparations from infected mice showed significant leishmanicidal activity. Mice receiving multiple inocula were more potent producers of leishmanicidal lymphokines than were those receiving single inocula. The expression of leishmanicidal activity in our system required continuous presence of the lymphokine preparation and was independent of trypsin- or neuraminidase-sensitive receptors of the macrophages. Light and electron microscopy revealed that, in the presence of lymphokines, macrophages appeared to be "activated," and intracellular leishmanias developed specific subcellular lesions in the kinetoplast-mitochondria. A time-course study showed that cultivation of the lymphocytes for 1 1/2 days completed the release of their leishmanicidal lymphokines which were heat-labile molecules larger than 50,000 daltons.

Preliminary demonstration of human tuberculoimmunity in vitro

In this paper a method for studying human tuberculoimmunity in vitro is described. Results from its use support an explanation for human tuberculoimmunity that is like that for mouse tuberculoimmunity: that immune lymphocytes are stimulated by being cultured with immunizing antigen to make a lymphokine which enables syngeneic macrophages to kill intracellular tubercle bacilli. This method uses antigen-responding lymphocytes and effector monocytes taken in the same original 20-ml sample of venous blood. These cells are cultured separately, the lymphocytes for 72 h with antigen to make immune lymphokine and the monocytes for 7 days to become macrophages. The macrophages are then infected with attenuated or virulent tubercle bacilli and cultured for 7 days more in medium with or without the immune lymphokine. Without it they are unable to control intracellular replication of the bacilli, whereas with it they do. This lymphokine was produced only by lymphocytes of immune subjects, of whom there were three kinds: tuberculin positive naturally immunized, Mycobacterium bovis BCG immunized, and trypsin-extracted bacillary antigen immunized. This method for detecting human tuberculoimmunity in vitro should be useful for comparing experimental vaccines and for studying cellular and molecular mechanisms of human tuberculoimmunity under better controlled conditions than hitherto have been possible.

Mycobacterium

Images

Partial characterization of a factor extracted from sensitized lymphocytes that inhibits the growth of Mycobacterium tuberculosis within macrophages in vitro

Spleen lymphocytes of BCG-immunized mice contain a soluble factor that inhibits in vitro the growth of the H37Rv strain of Mycobacterium tuberculosis within normal peritoneal macrophages. The water-soluble extracts of sensitized lymphocytes, disrupted by freezing and thawing, although less active than the corresponding viable cells retained a significant growth-inhibiting activity. Dialysis against distilled water, lyophilization, exposure to ribonuclease and deoxyribonuclease, and storage at -20 degrees C of the water-soluble extracts did not affect their antimycobacterial activity, whereas extracts heated at 100 degrees C were completely devoid of such an activity. All the inhibiting activity was recovered in the void volume of the column after chromatography on Sephadex G-200. Water-soluble constitutents of sensitized lymphocytes did not affect BCG grown in vitro, and on repeated treatments of tuberculous mice they led to a negligible protection against pulmonary tuberculosis. Preliminary observations seem to indicate that other soluble factors in lymphocytes of BCG-sensitized mice have the capacity to potentiate in vitro the phagocytic activity of normal macrophages.