title: Maintenance of memory CD8+ T cell diversity and proliferative potential by a primary response upon re-challenge.
abstract: Memory CD8+ T cells generated during an immune response are long lived and self-renewing, offering enhanced host protection against re-infection. However, how an antigen-specific population of memory T cells is maintained, throughout repetitive infections over potentially a lifetime, is not known. Here we show that a primary response during re-challenge significantly contributes to memory T cell pool both qualitatively and quantitatively. Upon re-challenge, the skewed Vbeta usage and TCR repertoire of pre-existing memory T cells is partly corrected by diversity in a newly primed (primary) T cell population. Importantly, this primary population expands more vigorously in a subsequent antigen encounter. These findings indicate that memory T cell populations evolve over multiple challenges, favoring memory T cells generated in more recent encounters, and suggest that these primary populations have essential roles in the perpetuation of antigen-specific T cell populations.
authors.affiliation: Department of Immunotherapeutics (Medinet), Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kurachi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kakimi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ueha
authors.forename: Kouji
authors.initials: K
authors.lastname: Matsushima
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D049109:Cell Proliferation; D007156:Immunologic Memory; D051379:Mice; D008810:Mice, Inbred C57BL; D016176:T-Lymphocyte Subsets / Q000276:immunology