Search results for "killer"
showing 10 items of 286 documents
Immunoregulatory role of Jα281 T cells in aged mice developing lupus-like nephritis
2007
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the emergence of autoreactive T cells. Humans and mice with SLE have reduced numbers of CD1d-restricted invariant natural killer T (iNKT) cells, suggesting a key role for these cells in its immunopathogenesis. This subset uses an invariant TCR constituted by Valpha14 Jalpha281 chains paired with some Vbeta domains. The regulatory role for iNKT cells in non-autoimmune mice was suggested by our previous results showing that aged Jalpha281 knockout (KO) mice produce anti-dsDNA. Here we show that old Jalpha281 KO mice have proteinuria and antibodies against dsDNA and cardiolipin. Histological analysis of Jalpha281 KO m…
Early activation of γδ T lymphocytes in the elderly
2001
T cell function is altered in vivo and in vitro in elderly compared with young subjects, and this alteration is believed to contribute to morbidity and mortality in man due to the greater incidence of infection, as well as autoimmunity and cancer in elderly. The majority of T cells express TCRalphabeta whereas TCRgammadelta is expressed on a minority of T cells. Moreover, it is known that gammadelta T lymphocytes display major histocompatibility complex (MHC)- unrestricted cytotoxicity that is reminiscent of natural killer (NK) activity. In view of earlier findings on both T cells and NK cells in the elderly, we hypothesised a different behaviour of gammadelta T lymphocytes from old subject…
Effects of in vitro treatment with fluticasone propionate on natural killer and lymphokine-induced killer activity in asthmatic and healthy individua…
2001
Background: Topical corticosteroids are beneficial in the treatment of allergic respiratory disorders; they exert effects on a number of cells involved in allergic inflammatory reactions. On the other hand, major histocompatibility complex (MHC)-unrestricted cytotoxicity (i.e., natural killer [NK] cell activity) may play a role in the inflammatory allergic reaction. The objective was to gain insight into the mechanisms of the therapeutic effects of fluticasone propionate (FP), an inhaled corticosteroid used in asthma and rhinitis therapy. Therefore, we evaluated the NK and lymphokine-activated killer (LAK) activity of effector cells in vitro treated or not with FP. Methods: Evaluations were…
Allogeneic stem cell transplantation for renal cell carcinoma
2011
Allogeneic hematopoietic stem cell transplantation from a compatible donor has been utilized as adoptive immunotherapy in metastatic, cytokine-refractory renal cell carcinoma (RCC). Since the year 2000, several investigators have established that RCC is susceptible to a graft-versus-tumor effect: they reported that patients with renal cancer may have partial or complete disease responses, in the 20-40% range, after allogeneic transplantation following a reduced-intensity regimen. However, transplant-related mortality is still high in the 10-20% range, and responses are rarely durable. Experimental evidence suggests that donor-derived T cells and natural killer cells are the main mediators o…
Aminobisphosphonate-activated γδ T cells in immunotherapy of cancer: doubts no more
2008
BACKGROUND: Activated V gamma 9 V delta 2 T cells are able to kill most tumour cells because of recognition by T cell receptor and natural killer receptors. OBJECTIVE: We discuss the possibility that the intentional activation of gammadelta T cells in vivo by aminobisphosphonates may represent a promising target for the design of novel and highly innovative immunotherapy in cancer patients. METHODS: The antitumoral effects of gammadelta T cells both in vitro and in vivo have been demonstrated suggesting a new therapeutic approach for translation into the clinical setting. RESULTS/CONCLUSION: V gamma 9 V delta 2 T lymphocytes represent a particularly interesting target for immunotherapeutic …
Embryonic neural cell adhesion molecules on human natural killer cells
1989
The neural cell adhesion molecules (NCAM) are surface glycoproteins that were first described in brain tissue. NCAM mediate adhesion in a variety of cell-cell interactions. In the present study we show that the so-called "embryonic" NCAM, i.e., the highly polysialylated forms of these proteins, are expressed on natural killer cells and some CD3+ cells in man. Homotypic binding of NCAM, believed to be of importance for cell-cell adhesion in neural tissues, appears not to be essential for NK cell-mediated killing. Yet, NCAM might be involved in NK cell migration, homing or related functions.
Depletion of alloreactive T cells via CD69: implications on antiviral, antileukemic and immunoregulatory T lymphocytes
2005
Selective depletion of alloreactive T cells from stem-cell allografts should abrogate graft-versus-host disease while preserving beneficial T cell specificities to facilitate engraftment and immune reconstitution. We therefore explored a refined immunomagnetic separation strategy to effectively deplete alloreactive donor lymphocytes expressing the activation antigen CD69 upon stimulation, and examined the retainment of antiviral, antileukemic, and immunoregulatory T cells. In addition to the CD69high T cell fraction, our studies retrieved two T cell subsets based on residual CD69 expression. Whereas, truly CD69(neg) cells were devoid of detectable alloresponses to original stimulators, CD69…
Clonal analysis of human T cell activation by the Mycoplasma arthritidis mitogen (MAS)
1988
Mycoplasma arthritidis produces an as yet undefined soluble molecule (MAS) that has a potent mitogenic effect on T cells of several species. We have used cloned human cytotoxic and proliferative T lymphocytes to dissect the molecular mechanism of T cell activation by this mitogen. Reactivity to MAS is clonally expressed among T cell receptor (TcR) alpha/beta chain-expressing T cell clones of CD4+ or CD8+ phenotype, as well as CD4-8- TcR alpha/beta chain-negative T lymphocyte clones expressing the CD3-associated TcR gamma chain. MAS is able to induce cytotoxicity and/or proliferation in these T cell clones. For triggering of these T cells, regardless of their phenotype of specificity, the pr…
Function of Dipeptidyl Peptidase IV (CD26, Tp103) in Transfected Human T Cells
1993
CD26 (Tp103) is a proteolytic enzyme (dipeptidyl peptidase IV) expressed on the T cell surface that defines an alternative activation signal for human T lymphocytes. It is absent from or present in only low amounts on resting T cells but it is expressed strongly after activation. Crosslinking of CD26/Tp103 via the monoclonal antibody CB.1 triggers functional activities in preactivated T cells. To study the molecular requirements for T cell activation via CD26 we transfected a cDNA encoding CD26 into several CD26-negative cells. In Jurkat T cell leukemia cells that normally do not express the CD26 antigen, the transfected CD26 molecule is functional because the monoclonal antibody CB.1 induc…
Stimulator cell-dependent requirement for CD2- and LFA-1-mediated adhesions in T lymphocyte activation by superantigenic toxins.
1992
Abstract The staphylococcal enterotoxins and related microbial T cell mitogens stimulate T cells by cross-linking variable parts of the T cell receptor (TCR) with MHC class II molecules on accessory or target cells. We have used cloned human T cells and defined tumor cells as accessory cells (AC) to study the requirements for T cell activation by these toxins. On AC expressing high levels of CD54 (intercellular adhesion molecule-1, ICAM-1) and CD58 (lymphocyte function-associated antigen-3, LFA-3), mAb to CD2 were relatively ineffective in inhibiting the response to the toxins and antibodies to the lymphocyte function-associated antigen-1 (LFA-1) did not inhibit at all. If added together, h…