Granule-mediated cell killing by cytotoxic lymphocytes requires the combined actions of a membranolytic protein, perforin, and granule-associated granzymes, but the mechanism by which they jointly kill cells is poorly understood. We have tested a series of membrane-disruptive agents including bacterial pore-forming toxins and hemolytic complement for their ability to replace perforin in facilit...

Growing interest in natural killer (NK) cell-based therapy for treating human cancer has made it imperative to develop new tools to measure early events in cell death. We recently demonstrated that protease-cleavable luciferase biosensors detect granzyme B and pro-apoptotic caspase activation within minutes of target cell recognition by murine cytotoxic lymphocytes. Here we report successful ad...

An interaction that gets things started he nuclear envelope clearly helps regulate eukaryotic DNA replication, but many of the molecular pieces of this process are still unknown. On page 177, Martins et al. describe a novel, direct interaction between the nuclear envelope and the genome, mediated by the inner nuclear membrane protein LAP2b and the nuclear matrix– associated protein HA95, that i...

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,...

The granzyme/perforin pathway is a major mechanism for cytotoxic lymphocytes to eliminate virus-infected and tumor cells. The balance between activation and inhibition of the proteolytic cascade must be tightly controlled to avoid self damage. Granzyme H (GzmH) is constitutively expressed in NK cells and induces target cell death; however, how GzmH activity is regulated remains elusive. We repo...

Killer lymphocytes induce apoptosis by the release of cytotoxic mediators from specialized secretory lysosomes, called cytotoxic granules, into the immunological synapse formed with a cell targeted for elimination. Methods are presented here for isolating CTL and NK cell cytotoxic granules using cell disruption by nitrogen cavitation followed by continuous Percoll density gradient fractionation...

The mechanism of target cell lysis in cytotoxic lymphocyte-mediated death is not well understood, and the role of granzymes in this process is unclear. Chemical functional probes were thus prepared for the major granzymes A and B to deconvolute their role in natural killer cell-mediated lysis of target cells. These biotinylated and substrate specificity-based diphenyl phosphonates allowed facil...

Lymphocytes from the synovial fluid of patients with rheumatoid arthritis were examined for the expression of granzyme A and perforin. Previous studies have demonstrated that the expression of these proteins, which are implicated as mediators of cytotoxicity, can be used to identify putative cytolytic lymphocytes in vivo. Twenty-two synovial fluid samples were analyzed by in situ hybridization ...

Glioblastoma multiforme (GBM), is the most common adult brain tumor and despite many new therapies, remains largely incurable. Regulatory T cells (Treg) are highly immunosuppressive cells that accumulate within glioma microenvironment, and reduction of their function or trafficking has been previously shown to enhance survival in pre-clinical models of GBM. One of the principal mechanisms of Tr...