Cytotoxic T lymphocytes and natural killer cells destroy target cells via the directed exocytosis of lytic effector molecules such as perforin and granzymes. The mechanism by which these proteins enter targets is uncertain. There is ongoing debate over whether the most important endocytic mechanism is nonspecific or is dependent on the cation-independent mannose 6-phosphate receptor. This study...

Killer lymphocytes provide powerful immune protection from cancer and infection by eliminating dangerous cells. Innate killer cells (principally natural killer cells) and innate-like T cells provide the first response. Antigen-specific immunity by cytotoxic T lymphocytes takes over about a week later and provides life-long immunity. When killer cells recognize a target cell, they mobilize cytot...

Cytotoxic lymphocytes possess a number of serine proteases (granzymes) usually localized in cytoplasmic granules. To date, the DNA sequences of four human granzymes have been reported. A fifth human granzyme (granzyme 3) has been biochemically purified and its N-terminal amino acid sequence has been reported. This enzyme was described as possessing tryptase activity, cleaving synthetic substrat...

In the past few years, cancer immunotherapy has emerged as a safe and effective alternative for treatment of cancers that do not respond to classical treatments, including those types with high aggressiveness. New immune modulators, such as cytokines, blockers of CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) and PD-1(programmed cell death protein 1)/PD-L1 (programmed death-ligand 1), and...

Human granzyme H is a neutral serine protease that is expressed predominantly in the lymphokine-activated killer (LAK)/natural killer (NK) compartment of the immune system. The gene that encodes this granzyme is located between the granzyme B and cathepsin G genes on human chromosome 14q11.2. Although the murine orthologue of human granzyme H has not yet been identified, murine granzymes C, D, ...

Cytotoxic lymphocytes kill bacteria-infected cells, but the mechanisms at work remain unclear. Walch et al. show that these lymphocytes deliver a toxic molecular trio in a two-step process, penetrating first the infected cells and then delivering bactericidal granzymes into the intracytoplasmic bacteria.

Cytotoxic T lymphocytes mediate lysis of target cells by various mechanisms, including exocytosis of lytic proteins (perforin, granzymes) and receptor-ligand binding of Fas/APO molecules. Death of target cells is characterized by either necrosis or apoptosis, depending on the killing mechanism used and on the metabolism of the target cell itself.

background: cd4+ and cd8+ t cells are the main types of lymphocytes in cell-mediated immunity and play a central role in the induction of efficient immune responses against tumors. the frequencies of t cell subtypes in the peripheral blood and tumor tissues, and draining lymph nodes (dln) can be considered as useful markers for evaluation of the immune system in cancers. methods: in this study,...