Process of disintegration and degradation of M. leprae: study of tissue imprints and tissues.
The existence, distribution and behaviour of degradation products of M. leprae in leprosy lesions were investigated in tissue specimens fixed in neutral formalin and embedded in paraffin. Cytopathologic findings using tissue imprints were unsatisfactory. Sections were stained with hematoxylin-eosin, acid-fast stains, silver methenamine and by an immunochemical (PAP) technique using serial paraffin sections. A comparison in respect of the distribution of the bacilli within the macrophages showed considerable differences between the superficial and deep granulomas. This corresponds roughly with the central, intermediary and peripheral locations. In a small granuloma seen in BL lesions, there were two zones: central and peripheral. In a large LL granuloma, three zones were seen, central, intermediary and peripheral zones. It is suggested that the degradation of disintegrated particles of bacilli might be due to the lysosymal activity of macrophages. The phagocytized bacilli are slowly degraded with long incubation periods, but the undigested debris remains inside the phagosomes. The chemical complexity of cytoplasm, cell wall and lipid fractions of M. leprae, and it is such that the lipid fractions of M. leprae mask some other antigenic components, which may be responsible for the cellular response and lysosymal production. According to our findings we believe that chemotherapy kills M. leprae but degraded products are not removed. These components are chemically complex and digested with difficulty. Lysosymal enzymes could be inhibited from productions by the bacterial debris or the lipid fractions could serve as a mask to delay lysosymal production in the cell. These aspects need further study.
Cologlu
A S
AS
Leprosy Research and Training Centre, University of Istanbul, Turkey.
D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D005260:Female; D006099:Granuloma / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D007918:Leprosy / Q000276:immunology / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009166:Mycobacterium leprae / Q000276:immunology / Q000378:metabolism*
D000942:Antigens, Bacterial