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Compartmentalization of the peripheral immune system
G Kroemer1, E Cuende, C Martínez
1Centro de Biología Molecular (CSIC), Universidad Autónoma de Madrid, Spain.
Advances in Immunology
|January 1, 1993
Summary
Peripheral immune cells, including B and T cells, show diverse development and function across different body sites. These nonconventional lymphocytes, rare in blood, populate tissues with unique antigen receptor repertoires and may arise from distinct lineages outside central organs.
Area of Science:
- Immunology
- Cell Biology
Background:
- The immune system's periphery harbors diverse B and T cell populations with unique phenotypes and functions, differing from those in central lymphoid organs.
- Nonconventional lymphocytes, such as alpha/beta TCR+CD4-CD8- and gamma/delta TCR+ T cells, and CD5+ B cells, are found at high frequencies in specific tissues.
Purpose of the Study:
- To investigate the divergent phenotypes, developmental origins, and functions of lymphocytes in the immune system's periphery.
- To explore the antigen receptor repertoire diversity and self-tolerance mechanisms in peripheral lymphocyte compartments.
Main Methods:
- Analysis of lymphocyte distribution and phenotype in various peripheral tissues (bone marrow, gut, epithelia, peritoneum).
- Characterization of antigen receptor gene expression (TCR and immunoglobulin) across different locations.
- Investigation of T cell populations, including self-superantigen-reactive and self-peptide-specific cells.
Main Results:
- Peripheral lymphocyte populations exhibit distinct antigen receptor repertoires, with varying gene expression levels across sites.
- Certain T and B cell populations appear to develop independently of the thymus and bone marrow, originating from nonconventional lineages.
- Evidence suggests local selection processes, influenced by antigens and microenvironments, shape peripheral lymphocyte diversity and function.
Conclusions:
- Peripheral lymphocyte compartmentalization leads to functional specialization and fragmented immunoregulatory circuits.
- These tissue-resident lymphocytes are likely involved in combating site-specific pathogens and self-proteins.
- Understanding peripheral lymphocyte diversity is crucial for comprehending local immune responses and self-tolerance.