Cytotoxic T lymphocytes are essential for defence against viral infections. Recent data demonstrating direct killing of intracellular bacteria by granulysin, a protein released from the granules of cytotoxic T lymphocytes, emphasize the contribution of these lymphocytes to the control of tuberculosis.

Cholinergic agonists have previously been shown to augment the ability of sensitized lymphocytes to injure cells bearing the sensitizing alleantigens. The cholinergic receptor of the attacking lymphocyte population has been studied with pharmacological manipulation of an in vitro system that quantitates the injury mediated by sensitized attacking cells upon target cells. The data reveal that mu...

A costimulatory signal in addition to an Ag-specific stimulus is required for optimal activation of T lymphocytes. CD28, the primary positive costimulatory receptor on T cells, has two identified ligands, B7-1 and B7-2. Whether B7-1 and B7-2 have identical, overlapping, or distinct functions remains unresolved. In this study, we show that mice lacking B7-2 were unable to generate CTL responses ...

Viral mutational escape from CD8(+) cytotoxic T lymphocytes (CTLs) is typically considered to be a dichotomous process and uncommon during chronic HIV-1 infection. Ex vivo passaging of HIV-1 from persons with chronic infection, however, revealed the evolution of many fixed substitutions within and around CTL-targeted regions, with an associated increase in replicative capacity. This indicates a...

The secretion of immunoglobulin by plasma cells has been considered a classical example of the "non-regulated" pathway of protein secretion, in which newly synthesized protein is processed by the Golgi, packaged into small vesicles, and immediately secreted without intracellular storage. In the case of lymphokine secretion by T lymphocytes, it is generally not clear whether this non-regulated p...

Significant cytotoxic lymphocyte-induced DNA fragmentation does not occur in four human target cells lysed by human natural killer lymphocytes, killer lymphocytes, or cytotoxic T lymphocytes. These results contrast with the extensive DNA fragmentation that occurs in murine target cells lysed by the analogous effector lymphocytes. Thus, DNA fragmentation, or the lack thereof, represents a specie...