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pubmed:abstractText |
Development of T cell lineages and the role of the thymus as a source of immature T cells in parotid (PG) and submandibular salivary glands (SMG) were studied in Fischer 344 rats using the Thy-1/CD45RC/RT6 expression model. In addition, the phenotypes of salivary gland lymphocytes were compared with other conventional and extrathymic populations. PG mononuclear cells consisted of T cells (38%), B cells (29%), and NK cells (4%). SMG had 19% T cells, 7% B cells, 37% NK cells, and an unusual population of CD3(-)/RT6(+) cells. In comparison with lymph node (LN), both PG and SMG were enriched in immature (Thy-1(+)) and activated (Thy-1(-)/CD45RC(-)/RT6(-)) T cells. Unchanged percentages of Thy-1(+) T cells in PG and SMG following short-term adult thymectomy indicated that immature salivary gland T cells had an extrathymic source. In contrast, thymectomy eliminated LN recent thymic emigrants. SMG had T cells with characteristics of extrathymic populations, expressing TCRgammadelta(+) (28%), the CD8alphaalpha homodimer (11%), and NKR-P1A (66%). Many SMG T cells expressed integrin alpha(E)beta(7). PG T cells resembled those isolated from LN in respect to TCR and CD8 isoform usage, but were enriched in alpha(E)beta(7)(+) T cells and in NKT cells. Thus, salivary gland mononuclear cells are composed of a variety of subpopulations whose distributions differ between SMG and PG and are distinct from LN. These studies provide a basis for further investigation of regionalization in the mucosal immune network and are relevant to the design of vaccine regimens and intervention during pathological immune processes.
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pubmed:affiliation |
Departments of. Anatomy and Cell Biology and Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201, USA. nosulliv@med.wayne.edu
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