Antigen presentation within the lymph node draining a site of infection is crucial for initiation of cytotoxic T cell responses. Precisely how this antigen presentation regulates T cell expansion in vivo is unclear. Here, we show that, in primary infection, antigen presentation peaks ≈3 days postinfection and then slowly decays until day 12. This prolonged antigen presentation is required for optimal expansion of naive CD8+ T cells, because early ablation of dendritic cells reduces the later CD8+ T cell response. Antigen presentation during secondary infection was 10-fold lower in magnitude and largely terminated by day 4 postinfection. Expansion of memory, but not naive, antigen-specific T cells was tightly controlled by perforin-dependent cytolysis of antigen-presenting cells. The ability of the memory T cells to remove antigen-presenting cells provides a negative-feedback loop to directly limit the duration of antigen presentation in vivo.
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 10 Apr 2007|
- Dendritic cell
- Immunological memory
- Influenza virus
- T lymphocyte