Intracellular Cu/Zn superoxide dismutase levels in T and non-T cells from normal aged subjects.
The decreased immune response associated with aging may, in part, reflect intrinsic age-related biochemical alteration in lymphocytes from older subjects. The 'reactive oxygen species hypothesis' of aging postulates that these molecules are involved in the modifications leading to cellular senescence. Superoxide dismutase (SOD), and in particular the Cu/Zn-dependent intracellular form, plays a critical role in the defense against these species, but it is controversial whether this function declines in lymphocytes in old age. We utilized two different methods to evaluate Cu/Zn SOD levels in T and non-T cells (CD3+, CD3-, CD4+, CD8+, CD16+) from young and old individuals: a specific and sensitive enzyme immunoassay performed on extracts of sorted cells, and a flow cytometry double fluorescence technique with monoclonal antibodies against Cu/Zn SOD and the different lymphocyte subsets. The Cu/Zn SOD cell content was assayed both in basal conditions and after peripheral blood lymphocyte stimulation with Concanavalin A, anti-CD3 monoclonal antibody and phorbol myristate acetate. In basal conditions, and considering the various subsets, no differences were found between young and old individuals, although data analysis revealed high and low responders in both groups. Taking all the subjects together, higher levels of this enzyme were found in CD3+ T lymphocytes, in particular in the CD4+ cells. After peripheral blood lymphocyte stimulation, Cu/Zn SOD concentration was higher than levels in unstimulated cells, both in young and old individuals, and particularly using Concanavalin A with respect to anti-CD3 and phorbol myristate acetate. In conclusion, the synthesis of Cu/Zn SOD does not seem to be affected by aging in proliferating cells. The highest levels of Cu/Zn SOD present in CD4+ cells, both from young and old individuals, may prevent the oxidant stress of these elements which play a major role in the inflammation sites.
Laboratorio di Immunologia e Genetica, Istituto di Ricerca Codivilla Putti, Bologna, Italy.
B
B
Grigolo
R M
RM
Borzì
E
E
Mariani
M C
MC
Monaco
L
L
Cattini
T
T
Porstmann
A
A
Facchini
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D000911:Antibodies, Monoclonal; D017252:CD3 Complex / Q000276:immunology; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D016131:Lymphocyte Subsets / Q000201:enzymology; D008297:Male; D012016:Reference Values; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013482:Superoxide Dismutase / Q000097:blood*; D013601:T-Lymphocytes / Q000201:enzymology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D003208:Concanavalin A; D013482:Superoxide Dismutase; D013755:Tetradecanoylphorbol Acetate