Superoxide radical(O2) is yielded by the metabolism of oxygen in cells
and known to exert either toxic effect or microbe-cidal action in cells with lysozymes.
In addition, it is also known to effect some changes in lipid metabolism as well as
inhibition of T-lymphocyte proliferation.
Superoxide dismutase (SOD), which catalytically scavenges the superoxide radicals, is
an important component of the biological defense mechanism against oxygen toxicity in
the organisms.
Leprosy can be classified into two polar forms, i.e., lepromatous and tuberculoid
leprosy, with clear cut patterns defined on the basis of clinical, histopathological,
microbiological and immunological parameters. In lepromatous leprosy, less severe but
generalized impairment of cell-mediated immunity(CMI) has heen demonstrated in
various ways both in vivo and in vitro. On the contrary, tuberculoid leprosy is known
to have well preserved CMI.
This study was undertaken to assess the SOD activities of the sera from leprosy
patients, as compared with normal subjects. The SOD activities were assayed by the
method of McCord and Fridovich (xanthine-xanthine oxidase system). One unit of SOD
activity was defined as the amount of the enzyme required to inhibit the rate of
reduction of cytochrome c by 50%, The SOD activities of the sera of normal subjects
(340±125 units/g protein:n=10) were not different significantly from those of tuberculoid
leprosy (364±108 units/9 protein:n=8) and those of lepromatous leprosy (315±95 units/g
protein:n=8).
These results suggest that the SOD activities in the sera may not reflect the changes
in the CMI of leprosy patients.
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