Mechanisms Involved in Age-dependent Decline of Immune Responsiveness and Apparent Resistance against Tolerance Induction in C57BL/6 Mice |
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| Authors: | T. AMAGAI K. NAKANO B. CINADER |
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| Affiliation: | Institute of Immunology, Departments of Medical Genetics, Clinical Biochemistry, and Medical Biophysics, University of Toronto, Toronto, Canada |
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| Abstract: | The plaque-forming antibody response of C57BL/6 mice to rabbit gamma globulin (RGG) decreases as a function of ae. RGG in tolerogenic form induces tolerance of young mice but sensitizes older animals. If antigen is administered together with lipopolysaccharide, the age-dependent decline in immune responsiveness is not observed, nor are older animals sensitized by tolerogen. The age-dependent decline in immune responsiveness is due to a loss of T helper capacity; sensitization by tolerogen is attributable to a subpopulation of B cells which becomes sensitized by the tolerogen. Older animals, treated with tolerogen, show a degree of central tolerance of T cells and a relatively slight, age-dependent diminution in colchicine- or cyclophosphamide-sensitive precursors of suppressor cells. |
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