Gene expression by antigen activated OT-I T cells in vivo in the presence and absence of IL-2

Much is known concerning the cellular and molecular basis for CD8+ T memory immune responses. Nevertheless, conditions that selectively support memory generation have remained elusive. Here we show that an immunization regimen that delivers TCR signals through a defined antigenic peptide, inflammatory signals through LPS, and growth and differentiation signals through the IL-2R initially favors antigen-specific CD8+ T cells to rapidly and substantially develop into tissue-residing T effector-memory cells by TCR transgenic OVA-specific OT-I CD8+ T cells. Amplified CD8+ T memory development depends upon a critical frequency of antigen-specific T cells and direct responsiveness to IL-2. A homologous prime-boost immunization protocol with transiently enhanced IL-2R signaling in normal mice led to persistent polyclonal antigen-specific CD8+ T cells that supported protective immunity to Listeria monocytogenes. These results identify a general approach for amplified T memory development that may be useful to optimize vaccines aimed at generating robust cell-mediated immunity.

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Castro I, Dee MJ, Malek TR