Age-related polymorphism of thymus subpopulations in inbred mice.
There are striking age-related changes in the demography of thymus lymphocytes, i.e. in thymus-cell subpopulations of BALB/c and SJL mice; these changes occur in the proportion of cells, identified by various markers, and by the membrane density of these markers. The thymuses of both strains undergo an age-related increase in the proportion of CD4+ CD8- cells and decrease in CD4+ CD8+ cells. Age-related changes in cells that are Pgp-1+ also show marked strain differences: Pgp-1+ cells increase in SJL, but not in BALB/c thymuses. In both strains, cells with high density of Pgp-1 appear in later life, though this is more marked in the thymus of SJL, which also shows a higher relative density at an advanced age, than do BALB/c mice. Furthermore, the per cent of cells with high density of Pgp-1 is larger in thymuses of SJL than in BALB/c mice. The percentage of CD45+ thymocytes remains unchanged, as animals age. Thymocyte-membrane densities of CD-45 undergo age-related increases in both SJL and BALB/c. The per cent of cells with high density of CD-45 is similar in both strains. Individual variations in relative size of subpopulations in SJL mice of the same age are greater in old than in young mice; this increase in heterogeneity is manifested by increase in standard deviation. Corresponding significant changes have not been observed in BALB/c or C57BL/6 mice. Thus, we have detected an intrastrain variation which may reflect age-related effects of the impact of stochastic events.
Department of Immunology, University of Toronto, Canada.
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Dubiski
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Cinader
D000375:Aging / Q000276:immunology*; D000818:Animals; D015415:Biomarkers; D015496:CD4-Positive T-Lymphocytes; D005260:Female; D017493:Leukocyte Common Antigens / Q000032:analysis; D007958:Leukocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C / Q000254:growth & development / Q000276:immunology; D008815:Mice, Inbred Strains / Q000254:growth & development / Q000276:immunology*; D011110:Polymorphism, Genetic; D016201:Receptors, Lymphocyte Homing / Q000032:analysis; D016176:T-Lymphocyte Subsets; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development*
D015415:Biomarkers; D016201:Receptors, Lymphocyte Homing; D017493:Leukocyte Common Antigens