title: Null cell senescence and its potential significance to the immunobiology of aging.
abstract: The null cell compartments of human bone marrow and mouse spleen were arbitrarily divided into three subpopulations based upon the ability of cells to acquire T or B cell membrane markers when incubated with poly A:U or ubiquitin. There was an accumulation of T cell precursors with congenital absence of the thymus. In contrast, T cell precursors were reduced and there was an accumulation of uninduced null cells with old age. These observations suggest that there is an intrinsic defect of null cell differentiation with a drift towards more differentiated precursors in T cell differentiation with aging. This could result in a diminution in the range of responses by their progeny, mature T lymphocytes.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology; D002454:Cell Differentiation; D006801:Humans; D007111:Immunity, Cellular; D008215:Lymphocytes, Null / Q000166:cytology* / Q000276:immunology / Q000502:physiology; D051379:Mice; D008809:Mice, Inbred C3H; D008819:Mice, Nude; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology