CD8+ T-cell memory: only the good ones last.

Generating long-lasting, protective CD8(+) T-cell memory via vaccination is critical for combating infectious diseases. Advances in the past year have provided many new insights into how memory CD8(+) T cells are generated. It is now recognized that CD8(+) T cells differentiate from 'effector memory' cells into 'central memory' cells, which are stably maintained and confer superior protective immunity. Furthermore, CD4(+) T-cell help plays an important role in guiding the differentiation of CD8(+) T cells into long-lasting, functional memory. These findings have important implications for developing vaccine strategies that induce high-quality CD8(+) T-cell memory, not just high quantity.