Search results for " T cell"
showing 10 items of 1161 documents
Changes of ICE protease activities caused by toxic supernatants of dinoflagellates (Prorocentrum species) from marine algal blooms
1999
Summary Marine phytotoxins may become a major health problem for humans because of their ability to contaminate seafood and to cause shellfish poisoning. In this report, the cytotoxic effects and the effects on intracellular caspase activities of culture supernatants from different dinoflagellate Prorocentrum clones were determined. Among the clones tested, P. tepsium BAH ME-140 and P. lima BAH ME-130 K1 and K2 clones but not P. minimum and P. micans were found to be toxic on rat pheochromocytoma PC12 cells, mouse lymphoma L5178Y cells and rat primary neurons. A significant increase in the specific activities of caspase 1 (ICE), caspase 3 (CPP32) and caspase 6 (Mch2) to 149–167% was observe…
Immunological Activity of Ascidian Hemocytes
2001
In ascidians, various hemocyte types and their differentiation stages may be responsible for several immune functions. A central role in the immune effector mechanisms can be assigned to PO-containing hemocytes and prophenoloxidase system. Morula cell in Styela plicata and univacuolar refringent granulocyte in Ciona intestinalis, a probable intermediate stages in the differentiation pathway of morula cell, may be cytotoxic cells. They are involved in immune reactions of solitary and colonial ascidians. We have shown that they are provided with a PO-linked spontaneous cytotoxic activity and recognize mammalian erythrocytes or tumor cells markers. The toxic molecules can be radical oxygen int…
A comparative study of the in vitro immunomodulatory activity of human intact immunoglobulin (7S IVIG), F(ab′) 2 fragments (5S IVIG) and Fc fragments…
1997
During the past few decades intravenous immunoglobulin (IVIG) has been used successfully in the treatment of various immunoregulatory disorders. Treatment results have been attributed to immunomodulation mainly via Fc receptors or by anti-idiotypic antibodies to disease-causing autoantibodies. From the present study it is clearly evident that 7S IVIG (intact immunoglobulin) as well as 5S IVIG [F(ab')2 fragments] and Fc fragments have a potent immunomodulatory capacity. We demonstrate that mainly 7S IVIG inhibits alloantigen-induced T-cell proliferation and generation of cytotoxic T lymphocytes. Reduced interleukin-2 (IL-2) protein levels in culture supernatants of IVIG-supplemented mixed ly…
Drivers of topoisomerase II poisoning mimic and complement cytotoxicity in AML cells
2019
Recently approved cancer drugs remain out-of-reach to most patients due to prohibitive costs and only few produce clinically meaningful benefits. An untapped alternative is to enhance the efficacy and safety of existing cancer drugs. We hypothesized that the response to topoisomerase II poisons, a very successful group of cancer drugs, can be improved by considering treatment-associated transcript levels. To this end, we analyzed transcriptomes from Acute Myeloid Leukemia (AML) cell lines treated with the topoisomerase II poison etoposide. Using complementary criteria of co-regulation within networks and of essentiality for cell survival, we identified and functionally confirmed 11 druggabl…
Tumoricidal Activity of Endothelial Cells
2001
The mechanism of NO- and H(2)O(2)-induced tumor cytotoxicity was examined during B16 melanoma (B16M) adhesion to the hepatic sinusoidal endothelium (HSE) in vitro. We used endothelial nitric-oxide synthetase gene disruption and N(G)-nitro-l-arginine methyl ester-induced inhibition of nitric-oxide synthetase activity to study the effect of HSE-derived NO on B16M cell viability. Extracellular H(2)O(2) was removed by exogenous catalase. H(2)O(2) was not cytotoxic in the absence of NO. However, NO-induced tumor cytotoxicity was increased by H(2)O(2) due to the formation of potent oxidants, likely ( small middle dot)OH and (-)OONO radicals, via a trace metal-dependent process. B16M cells culture…
Murine Model of Cytomegalovirus Latency and Reactivation
2008
Efficient resolution of acute cytopathogenic cytomegalovirus infection through innate and adaptive host immune mechanisms is followed by lifelong maintenance of the viral genome in host tissues in a state of replicative latency, which is interrupted by episodes of virus reactivation for transmission. The establishment of latency is the result of aeons of co-evolution of cytomegaloviruses and their respective host species. Genetic adaptation of a particular cytomegalovirus to its specific host is reflected by private gene families not found in other members of the cytomegalovirus group, whereas basic functions of the viral replicative cycle are encoded by public gene families shared between …
SAT0373 Role of Inkt Cells in Patients with Primary Sjogren Syndrome
2015
Background iNKT cells represent a T cell subset at the bridge between innate and adaptive immunity, playing a role in regulating auto-antibody-producing B cells before their entry into germinal centers. Therefore the absence and/or reduction of iNKT cells seem to increase auto-reactive B cell activation. Primary Sjogren9s syndrome (pSS) is a systemic autoimmune disease in which lymphocyte infiltration and organization in lymphoid structures of inflamed salivary glands occur. Objectives The aim of this study was to investigate the frequency of iNKT in the salivary glands and peripheral blood of patients with pSS and their function by using CD1d/aGalactosylceramide (aGalaCer) tetramers. Metho…
Cutaneous Leishmania infection: progress in pathogenesis research and experimental therapy.
2007
Studies in murine experimental Leishmania major infection have helped to understand the requirements for efficient development of T helper (Th)1/cytotoxic T (Tc)1-mediated protection against the parasite. As such they have revealed that Fc gamma receptor (Fc gamma R)I and Fc gamma RIII-mediated uptake of L. major amastigotes by dendritic cells (DC) is an important prerequisite for Th1 development. In addition, DC-derived cytokines contribute to adequate T-cell education. DC-based vaccines may thus provide an important tool for both the development of a prophylactic vaccine against leishmaniasis and - together with leishmanicidal drugs - for eliciting immune-deviating functions towards prote…
The CD38-Positive and CD38-Negative Subsets of CD34(high)-Positive Primary Acute Myeloid Leukemia Blasts Differ Considerably in the Expression of Imm…
2008
Abstract Acute myeloid leukemia (AML) is thought to arise from a rare putative ‘leukemic stem cell’ that is capable of self-renewal and formation of leukemic blasts. Serial xenotransplantation studies in immunodeficient mice have shown that this leukemia-initiating cell resides at very low numbers within CD34(high)-positive CD38-negative AML cells. Thus, immunotherapeutic approaches successfully eradicating this cell compartment should result in cure from disease. The objective of our study was to characterize the immune phenotype of the CD38-negative and CD38-positive subsets of primary CD34(high)-positive AML blasts ex vivo. We obtained therapeutic leukapheresis products from 17 AML patie…
EFFECT OF M-LOCUS DEPENDENT T-CELL PROLIFERATION UPON THE INDUCTION OF ANTI H-2 CYTOTOXIC T EFFECTOR CELLS
1975
SUMMARY The influence of M-locus dependent T cell proliferation on the induction of anti H-2 cytotoxic T lymphocytes (CTL) was tested in an in vitro murine cytotoxic allograft model. BALB/c (or CBA/H) derived responder cells (H-2d or H-2k) were cultured together with either C57BL derived fibroblasts or C57BL derived (H-2b), U.V. light irradiated, splenic lymphocytes. These stimulator cells lack functionally active lymphocyte activating determinants (LADs), but display serologically defined (SD) H-2 antigenic specificities. The cytotoxic anti SD-activity obtained was weak. Under certain experimental conditions, the addition of stimulator cells which are H-2 identical to the responder cells b…