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Recent Thymic Emigrants (CD4 + ) Continuously Migrate Through Lymphoid Organs: within the Tissue They Alter Surface Molecule Expression
Author(s) -
Luettig B.,
Sponholz A.,
Heerwagen C.,
Bode U.,
Westermann J.
Publication year - 2001
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1046/j.1365-3083.2001.00897.x
Subject(s) - cd90 , biology , cd44 , homing (biology) , bone marrow , spleen , population , lymphatic system , lymph node , cluster of differentiation , flow cytometry , immunology , progenitor cell , microbiology and biotechnology , pathology , stem cell , cell , medicine , ecology , environmental health , genetics
T‐cell progenitors migrate from bone marrow (BM) into the thymus. After maturation they are released as recent thymic emigrants (RTE) into the periphery ensuring the diversification of the T‐cell repertoire. Both the kinetics with which RTE migrate through the periphery and the surface molecules they express are still unclear. In 1‐ and 18‐month‐old Lewis rats CD4 + RTE were identified in blood, spleen, lymph node, and thoracic duct lymph by flow cytometry (CD45RC − and CD90 + ), were differentiated from CD4 + naive (CD45RC + ) and memory T cells (CD45RC − CD90 − ), and were characterized regarding the expression of surface molecules. Both in 1‐ and 18‐month‐old animals the percentage of RTE among the CD4 + population in blood was comparable to that in all other compartments. Surprisingly, RTE expressed α 4 ‐integrin, LFA‐1, and interleukin (IL)‐2 receptor at a significantly higher level than naive T cells and more comparable to memory T cells. Within lymphoid tissues RTE, naive, and memory T cells significantly upregulated the expression of CD44 and ICAM‐1, and downregulated the expression of l ‐selectin. These changes were reversed before the cells re‐entered the blood. Thus, our data indicate that CD4 + RTE travel through the periphery of young and old rats like mature T cells, continuously modulating their surface molecule expression.