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Dwindling competition with constant demand: can homeostatic adjustments explain age-associated changes in peripheral
William J Quinn1, Jean L Scholz, Michael P Cancro
1University of Pennsylvania School of Medicine, Department of Pathology and Laboratory Medicine, 284 John Morgan Building, 36th And Hamilton Walk, Philadelphia, PA 19104-8062, USA.
Seminars in Immunology
|June 23, 2005
Summary
Aging alters B cell selection by relaxing specificity controls. Compensatory homeostatic processes in the bone marrow and periphery may explain the increased frequency of autoreactive B cells observed in older individuals.
Area of Science:
- Immunology
- Aging Research
- Cell Biology
Background:
- Peripheral B cell pools are maintained by specificity-based selection and homeostatic processes.
- Age-associated changes in B cell subsets may stem from homeostatic responses to cellular damage.
- B lymphocyte populations undergo significant age-related shifts in size and dynamics.
Purpose of the Study:
- To investigate the interplay between aging, homeostasis, and B cell selection.
- To propose a model explaining age-related increases in autoreactive B cells.
Main Methods:
- Analysis of age-associated changes in B lymphocyte subsets and progenitors.
- Modeling of homeostatic adjustments at the marrow-periphery interface.
Main Results:
- Aging causes perturbations in B lineage precursors, reducing immature B cell production.
- Compensatory homeostatic processes at the marrow-periphery interface offset these reductions.
- These adjustments appear to relax the stringency of specificity-based selection.
Conclusions:
- Age-related homeostatic adjustments in B cell populations may lead to decreased selection stringency.
- This relaxation provides a potential mechanism for the increased frequency of autoreactive specificities with age.