CD8+ T-cell selection, function, and death in the primary immune response in vivo
Margaret F.C. Callan, Chrysoula Fazou, Hongbing Yang, Tim Rostron, Kathryn Poon, Chris Hatton, Andrew J. McMichael
Margaret F.C. Callan, Chrysoula Fazou, Hongbing Yang, Tim Rostron, Kathryn Poon, Chris Hatton, Andrew J. McMichael
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CD8+ T-cell selection, function, and death in the primary immune response in vivo

Abstract

The primary immune response to Epstein Barr virus (EBV) is characterized by striking proliferation of EBV-specific CD8+ T cells. In this study we have investigated the clonal composition and functional properties of the cells mediating this primary response and have analyzed the mechanisms that control the downregulation of the primary response and the selection of memory cells. We show that massively expanded T-cell clones often dominate the primary antigen-specific T-cell response. Despite the enormous extent of expansion, the virus-specific T cells express high levels of intracellular perforin and are potently cytotoxic. They are, however, functionally heterogeneous in their ability to secrete proinflammatory cytokines, with subpopulations of the antigen-specific T cells being hyporesponsive. The primary response is closely regulated, and the majority of cells are programmed to die via a cytokine-rescuable pathway, leaving only small populations of memory T cells surviving. Comparison of the clonal composition of primary and memory responses in vivo shows that the clones that dominate the primary response are relatively heavily culled during the downregulation of the primary response and the establishment of T-cell memory.

Authors

Margaret F.C. Callan, Chrysoula Fazou, Hongbing Yang, Tim Rostron, Kathryn Poon, Chris Hatton, Andrew J. McMichael

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Models for the development of T-cell memory. (a) Primary and memory popu...
Models for the development of T-cell memory. (a) Primary and memory populations of T cells may derive from different naive precursors. The TCR use of the primary and memory populations would not be closely related. (b) Naive T cells differentiate to form a primary population. A minority of these cells persist into memory, while the majority die. The TCR use of the memory population would be identical to, or possibly more restricted than, that of the primary population. (c) Naive T cells differentiate to form an intermediate core cell from which both an expanded primary population (destined to die) and a memory population may derive. The TCR use of the memory population would be similar to that of the primary population, but relative depletion of the clonotypes most expanded during the primary response might occur.