Search results for "immune system"
showing 10 items of 2885 documents
Gene transfer of the Co-stimulatory molecules B7-1 and B7-2 enhances the immunogenicity of human renal cell carcinoma to a different extent.
1999
Stimulation of a specific antitumour immune response with recruitment and induction of T-cell effector functions represents an attractive concept in human cancer therapy. Different cytokines and the B7 co-stimulatory molecules are both able to provide proliferation and activation signals for T cells. In the present study, we first demonstrated the absence of both B7-1 and B7-2 expression in human renal cell carcinoma (RCC) cell lines. The lack of B7 expression was associated with a low or absent proliferative response of allogeneic and autologous T cells upon stimulation with tumour cells. In order to investigate the role of B7-1 and B7-2, the human RCC cell line, MZ1257RC, which expresses …
Mechanical Regulation of the Cytotoxic Activity of Natural Killer Cells
2020
AbstractMechanosensing has been recently explored for T cells and B cells and is believed to be part of their activation mechanism. Here, we explore the mechanosensing of the third type of lymphocytes – Natural Killer (NK) cells, by showing that they modulate their immune activity in response to changes in the stiffness of a stimulating surface. Interestingly, we found that this immune response is bell-shaped, and peaks for a stiffness of a few hundreds of kPa. This bell-shape behavior was observed only for surfaces functionalized with the activating ligand MHC class I polypeptide-related sequence A (MICA), but not for control surfaces lacking immunoactive functionalities. We found that sti…
Inefficient Termination of Antigen Responses in NF-ATp-Deficient Mice
1998
In order to elucidate the role of NF-ATp, one of the most prominent members of family of NF-AT transcription factors in peripheral T lymphocytes, in T cell activation and differentiation we created NF-ATp-deficient mice by gene targeting. Such NF-ATp-/- mice are born and appear to develop a normal immune system. Apart from clear-cut defects in the synthesis of mRNAs for Th2-type lymphokines, such as IL-4, IL-5, IL-10 and IL-13, in primary and secondary stimulations of spleen cells in vitro, of a distinct impaired deletion of V beta 11+/CD4+ T lymphocytes from these mice was detected after superantigen injection. Moreover, NF-ATp-/- mice older than 6 weeks show an 2-5 fold increase in number…
A Superantigen as Virulence Factor in an Acute Bacterial Infection
1994
This study addresses the role of a bacterial superantigen as a potential virulence factor during an acute systemic infection. BALB/c mice were intravenously infected with a recombinant Staphylococcus aureus strain capable of producing plasmid-encoded staphylococcal enterotoxin B (SEB) or with the SEB plasmid-deficient parental strain. Infection with SEB-producing bacteria resulted in an initial expansion and subsequent decrease of circulating V beta 8+ T lymphocytes. This numeric decrease was accompanied by a SEB-specific state of hyporesponsiveness of splenic T cells. In parallel with SEB-triggered unresponsiveness of a large proportion of T lymphocytes, a weakening of the overall T cell r…
Host immune response to Cryptosporidium parvum infection
2010
Species of the genus Cryptosporidium are protozoan parasites (Apicomplexa) that cause gastroenteritis in animals and humans. Of these Cryptosporidium parvum and Cryptosporidium hominis are the major causative agents of human cryptosporidiosis. Whereas infection is self-limiting in the immunocompetent hosts, immunocompromised individuals develop a chronic, life-threatening disease. As specific therapeutic or preventive interventions are not yet available, better understanding of the immune response to the parasite is required. This minireview briefly summarizes the factors involved in the innate and acquired immune response in this pathogen-host interaction with an emphasis on more recent da…
Different Efficiency of Heat Shock Proteins (HSP) to Activate Human Monocytes and Dendritic Cells: Superiority of HSP60
2002
Abstract One essential immunoregulatory function of heat shock protein (HSP) is activation of the innate immune system. We investigated the activation of human monocytes and monocyte-derived dendritic cells (DC) by recombinant human HSP60, human inducible HSP72, and preparations of human gp96 and HSP70 under stringent conditions, in the absence of serum and with highly purified monocytes. HSP60 induced human DC maturation and activated human DC to secrete proinflammatory cytokines. HSP72 induced DC maturation to a lesser extent, but activated human monocytes and immature DC as efficiently as HSP60 to release proinflammatory cytokines. The independence of the effects of HSP60 and HSP72 from …
Disruption of T helper 2-immune responses in Epstein–Barr virus-induced gene 3-deficient mice
2002
Epstein–Barr virus-induced gene 3 (EBI3) is a widely expressed IL-12p40-related protein that associates as a heterodimer with either IL-12p35 or an IL-12p35 homologue, p28, to create a new cytokine (IL-27). To define the function of EBI3in vivo, we generated knockout mice in which theebi3gene was targeted by homologous recombination. EBI3−/−mice exhibited normal numbers of both naive and mature CD4+and CD8+T cells and B cells, but markedly decreased numbers of invariant natural killer T cells (iNKT) as defined by staining with an α-galactosylceramide (αGalCer)-loaded CD1d-tetramer. iNKT cells from EBI3−/−mice exhibited decreased IL-4 and, to a lesser extent, IFN-γ production after αGalCer s…
Shared determinants between virus-infected and trinitrophenyl-conjugated H-2-identical target cells detected in cell-mediated lympholysis
1976
Infection of H-2-identical mice with either lymphocytic choriomeningitis (LCM) virus, vaccinia virus, or paramyxo (Sendai) virus resulted in the generation of specifically sensitized cytotoxic T lymphocytes (CTL). CTL generated in vitro against 2,4,6-trinitrophenyl (TNP)-conjugated syngeneic stimulator cells were specifically cytotoxic for TNP-conjugated H-2K (D) region identical targets. Both LCM and vaccinia-induced CTL, however, were found to be strongly cytotoxic towards TNP-conjugated, H-2K(D) region-identical target cells. In contrast, Sendai virus-induced CTL did not lyse TNP-conjugated, syngeneic target cells. Inhibition experiments using cold targets suggested that shared antigenic…
A contribution to the mathematical modeling of immune-cancer competition
2018
Abstract This paper deals with the modeling of interactions between the immune system and cancer cells, in the framework of the mathematical kinetic theory for active particles. The work deepens a previous paper of Belloquid et al. that assumes spatial homogeneity and discrete values of the activity of cancer and immune cells. A number of simulations are made with the aim to investigate how the state of the various cell populations evolves in time depending on the choice of the free parameters.
Development of spontaneous airway changes consistent with human asthma in mice lacking T-bet.
2002
Human asthma is associated with airway infiltration by T helper 2 (TH2) lymphocytes. We observed reduced expression of the TH1 transcription factor, T-bet, in T cells from airways of patients with asthma compared with that in T cells from airways of nonasthmatic patients, suggesting that loss of T-bet might be associated with asthma. Mice with a targeted deletion of the T-bet gene and severe combined immunodeficient mice receiving CD4+cells from T-bet knockout mice spontaneously demonstrated multiple physiological and inflammatory features characteristic of asthma. Thus, T-bet deficiency, in the absence of allergen exposure, induces a murine phenotype reminiscent of both acute and chronic h…