Memory-Like CD8+ T Cells Generated during Homeostatic Proliferation Defer to Antigen-Experienced Memory Cells

• Published in: The Journal of immunology (1950) Vol. 183; no. 5; pp. 3364 - 3372
• Main Authors: Cheung, Kitty P, Yang, Edward, Goldrath, Ananda W
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 01-09-2009
• Subjects: Animals; Antigens, Differentiation, T-Lymphocyte - immunology; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; Cell Differentiation - immunology; Cell Movement - immunology; Cell Proliferation; Homeostasis - immunology; Immunologic Memory; Lymphopenia - immunology; Lymphopenia - pathology; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Signal Transduction - immunology; Spleen - cytology; Spleen - immunology; Spleen - metabolism; T-Lymphocyte Subsets - cytology; T-Lymphocyte Subsets - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.0900641

Naive T cells proliferate in response to lymphopenia and acquire the phenotypic and functional qualities of memory T cells, providing enhanced protection against infection. How well memory-like T cells generated during lymphopenia-induced homeostatic proliferation (HP)-memory differentiate into secondary memory cells and compete with Ag-experienced true-memory cells is unknown. We found that CD8(+) HP-memory T cells generated robust responses upon infection and produced a secondary memory population comparable to true-memory cells in the absence of competition. However, when true-memory and HP-memory T cells competed during infection, HP-memory cells contributed less to the effector population, contracted earlier, and formed fewer secondary memory cells. Furthermore, HP- and true-memory cells demonstrated distinct chemokine receptor expression and localization within the spleen during infection, indicating differential access to signals necessary for secondary memory formation. Thus, HP-memory T cells provide protection without compromising the true-memory population. Differences in HP- and true-memory T cells may reveal the basis of competition for limited resources within the memory-T cell compartment.