title: Old mice recover the ability to produce IgG and high-avidity antibody following irradiation with partial bone marrow shielding.
abstract: The splenic plaque-forming-cell (PFC) response to trinitrophenylated bovine gamma globulin of 18- to 20-month-old mice is markedly depressed, with a preferential loss of indirect (IgG) PFC and high-avidity-antibody-secreting cells compared to 6- to 8-week-old animals. The anti-trinitrophenyl response of old mice, whose peripheral lymphoid system has been reconstituted from their own bone marrow after irradiation while their bone marrow was partially shielded, includes high-avidity and IgG PFCs relatively comparable to those of normal young mice. If young mice are irradiated while their bone marrow is partially shielded and given purified splenic T cells from either old or young donors during recovery from irradiation, then the avidity distribution and the ratio of IgG/IgM PFCs they produce in response to trinitrophenylated bovine gamma globulin reflects the characteristic immune response of the T-cell donor. These results are consistent with the hypothesis that the bone marrows of old and young mice are similar with regard to the spectrum of B-cell clones that they can generate and that it is peripheral regulatory effectors that are responsible for much of the age-related change in the immune response. In addition, if one calculates the PFC avidity distribution taking into account those cells whose secretion of antibody was inhibited by anti-idiotype autoantibodies, then it is clear that there are more high-avidity B cells present in old mice than are detected by the conventional plaque-inhibition assay. Thus, the reduced avidity of the PFC response of old mice appears to be, at least in part, due to down regulation by anti-idiotype autoantibodies.
authors.affiliation: Department of Medicine, Cornell University Medical College, New York, NY 10021.
authors.forename: T
authors.initials: T
authors.lastname: Tsuda
authors.forename: Y T
authors.initials: YT
authors.lastname: Kim
authors.forename: G W
authors.initials: GW
authors.lastname: Siskind
authors.forename: M E
authors.initials: ME
authors.lastname: Weksler
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D000915:Antibody Affinity; D000917:Antibody Formation / Q000528:radiation effects*; D000921:Antibody-Producing Cells / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology; D001853:Bone Marrow / Q000502:physiology*; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D008221:Lymphoid Tissue / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL / Q000276:immunology; D013154:Spleen / Q000276:immunology / Q000637:transplantation; D013601:T-Lymphocytes / Q000637:transplantation
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes