Changes in hydrolytic enzyme activities in armadillos infected with Mycobacterium leprae.

The activities of hydrolytic enzymes in various organs of armadillos infected with Mycobacterium leprae were compared with those in normal armadillos. Except for aspartate aminopeptidase and esterase, the levels of the other enzymes in liver, spleen and inguinal lymph nodes were significantly higher in armadillos infected with M. leprae compared with those in non-infected ones. These enzymes levels were at a maximum when the animals were sacrificed 22 to 30 months post-inoculation, a period when the bacterial load in the animals had also reached a maximum. Animals infected with M. leprae but not showing any signs of disseminated infection behaved similar to those in the non-infected group. The observed changes in enzymatic activities were not due to bacterial enzymes and so can be related to tissue damage caused by M. leprae.

Lysozyme and angiotensin converting enzyme levels in experimental mycobacterial granulomas.

A study has been made on mycobacterial-induced granulomas in guinea-pig lymph nodes. Lysozyme and angiotensin-converting enzyme (ACE) were measured in the auricular lymph nodes and serum of guinea-pigs which had received live BCG (Pasteur) or Cobalt (Co)-irradiated armadillo-derived Mycobacterium leprae intradermally into the ear or dinitrofluorobenzene (DNFB) painted epicutaneously upon the ears. In the lymph nodes with granulomas induced by either live BCG or killed M. leprae, the mean concentrations of lysozyme and ACE varied directly with the mean weight of the lymph nodes but the temporal pattern of weight change differed with the two agents. In M. leprae recipients at the time of peak lymph node weight, serum lysozyme and ACE values were significantly greater than those observed in controls; in animals receiving live BCG (Pasteur), serum lysozyme but not ACE values were elevated significantly at the time of peak lymph node weight. Four days following the epicutaneous application of DNFB, where there was no granuloma, there was a similar increase in the concentration of lysozyme and ACE in the lymph nodes. At the same time, there was also significant elevation in the serum lysozyme and ACE concentrations. Thus, in the granulomatous responses, the parallel tissue and serum changes in lysozyme and ACE concentrations were consistent with increased production and secretion of each enzyme by cells of the mononuclear phagocyte series. The increased lysozyme and ACE concentrations found in the lymph nodes of DNFB sensitised animals gives further evidence that such changes are not unique to granulomas. Finally, the intradermal administration of dead M. leprae in guinea pigs also produced increased lysozyme and ACE levels similar to that found in leprosy in man.

Muramidase content of cells in human granulomatous reactions.

The muramidase content of reactive cells in the lesions of human foreign body reactions, lepromatous and tuberculoid leprosy, sarcoidosis, tuberculosis, and granulomatous hepatitis, was assessed using specific anti-human muramidase antiserum and a peroxidase-anti-peroxidase marker system. Epithelioid and giant cells in sarcoidosis, tuberculosis, granulomatous hepatitis, and tuberculoid leprosy all showed the presence of muramidase in their cytoplasm. The muramidase content of macrophages in foreign body reactions and lepromatous leprosy varied and most multinucleate cells in these lesions gave a negative reaction. Possibly varying rates of muramidase secretion may account for these differences.