Type II pneumocyte-CD8+ T-cell interactions. Relationship between target cell cytotoxicity and activation.

CD8 + T-cell responses play an important role in the clearance of respiratory virus infection, but may also contribute to lung injury in the process. The effector mechanisms involved in viral clearance and associated lung injury include both cytolytic and noncytolytic effector functions. Previously we have shown that CD8 + T-cell recognition of alveolar epithelial cells triggers chemokine expression by the epithelial cell and that this plays an important role in the inflammatory infiltration that ensues in the context of T cell–mediated injury (Zhao and colleagues, J. Clin. Invest. 2000;106:R49–R58). In the present study we sought to understand the relationship between alveolar cell cytotoxicity and chemokine expression, both of which occur as a result of CD8 + T-cell antigen recognition. Alveolar epithelial cells efficiently process and present overlapping viral epitopes, and CD8 + T-cell recognition of these class I major histocompatibility complex–restricted epitopes resulted in cytotoxicity of the alv...