Increased numbers of preexisting memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells. J Immunol 2011 Oct 15;187(8):4068-76
Date
09/21/2011Pubmed ID
21930973Pubmed Central ID
PMC3991478DOI
10.4049/jimmunol.1002145Scopus ID
2-s2.0-80054722812 (requires institutional sign-in at Scopus site) 74 CitationsAbstract
Memory CD8 T cells acquire effector memory cell properties after reinfection and may reach terminally differentiated, senescent states ("Hayflick limit") after multiple infections. The signals controlling this process are not well understood, but we found that the degree of secondary effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and preexisting memory CD8 T cell number (i.e., primary memory CD8 T cell precursor frequency) present during secondary infection. Compared with naive cells, memory CD8 T cells were predisposed toward terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of Ag. TE cell formation after secondary (2°) or tertiary infections was dependent on increased T-bet expression because T-bet(+/-) cells were resistant to these phenotypic changes. Larger numbers of preexisting memory CD8 T cells limited the duration of 2° infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2° TE CD8 T cells that formed. Together, these data show that over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with Ag or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by preexisting memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies.
Author List
Joshi NS, Cui W, Dominguez CX, Chen JH, Hand TW, Kaech SMMESH terms used to index this publication - Major topics in bold
AnimalsCD8-Positive T-Lymphocytes
Cell Differentiation
Cell Separation
Cellular Senescence
Enzyme-Linked Immunosorbent Assay
Flow Cytometry
Immunologic Memory
Inflammation
Mice
Mice, Transgenic
T-Box Domain Proteins
T-Lymphocyte Subsets
