Apoptosis in the regulation of immune responses.

Apoptosis, or programmed cell death, is an active process required for the regulation of immune responses. T cell apoptosis may represent a protective mechanism that limits peripheral damage by T cells during immune response. The underlying biological processes responsible for morphological aspects of apoptosis are becoming better defined. Concepts reviewed here include caspase activation, death pathways, and crosstalk between death ligands and their receptors.