scholarly journals Helper T cells are required for the polyclonal stimulation of cytotoxic T cells by concanavalin A.

1977 ◽  
Vol 145 (5) ◽  
pp. 1237-1249 ◽  
Author(s):  
L M Pilarski ◽  
P A Bretscher ◽  
L L Baum
Keyword(s):  
T Cells ◽  
T Cell ◽  
Concanavalin A ◽  
Cytotoxic T Cells ◽  
Culture Conditions ◽  
Adherent Cell ◽  
T Helper ◽  
Effector Cells ◽  
Cell Functions ◽  
Stimulation Of

Concanavalin A stimulation of T-cell cytotoxicity has been shown to be absolutely dependent on helper T-cell collaboration. Thymocytes stimulated with ConA do not differentiate to yield cytotoxic effector cells. However, thymocytes cocultured with irradiated spleen cells as helpers and ConA yield high levels of cytotoxicity. The helper cell bears theta antigens on its surface, is not an adherent cell, and does not require any adherent cell functions in our culture conditions. The ConA-dependent helper cells appear to be polyclonal in specificity. Thus, polyclonal stimulation of cytotoxicity by ConA requires T helper-T precursor collaboration in analogy to antigen-specific T helper-T precursor interactions. Unlike the antigen-specific interacitons, the ConA-driven cytotoxicity does not appear to require linked associative recognition for induction of cytotoxicity.

scholarly journals Concanavalin A-inducible, interleukin-2-producing T cell hybridoma.

1980 ◽  
Vol 152 (4) ◽  
pp. 893-904 ◽  
Author(s):  
L Harwell ◽  
B Skidmore ◽  
P Marrack ◽  
J Kappler
Keyword(s):  
T Cells ◽  
T Cell ◽  
Concanavalin A ◽  
Interleukin 2 ◽  
Hybridoma Cells ◽  
Adherent Cell ◽  
Spleen Cells ◽  
Con A ◽  
Normal Spleen ◽  
Stimulation Of

The fusion of an AKR T cell tumor line to normal B6D2F1, T cells resulted in the production of a cloned T cell hybridoma (FS6-14.13) inducible with the mitogen concanavalin A (Con A). The supernate from Con A-stimulated hybridoma cells was active both in the stimulation of an anti-sheep red blood cell response by partially T cell-depleted B cells and in the stimulation of the growth of antigen-specific T cell blasts. The active principle in both assays had a molecular weight of approximately 30-40,000. These results indicated the presence of interleukin 2 (IL2) in the hybridoma supernate. The activity of the hybridoma supernate in B cell responses was dependent on the presence of adherent cells and a few contaminating T cells. On the other hand, Con A-stimulated supernates from normal spleen cells were active after either adherent cell removal or severe T cell depletion. These results suggested that IL2 was the only active helper factor in the hybridoma supernate, but that additional helper factors were present in supernates from Con A-stimulated normal spleen cells.

scholarly journals Low-Dose Cyclophosphamide Synergizes with Dendritic Cell-Based Immunotherapy in Antitumor Activity

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Joris D. Veltman ◽  
Margaretha E. H. Lambers ◽  
Menno van Nimwegen ◽  
Sanne de Jong ◽  
Rudi W. Hendriks ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Regulatory T Cells ◽  
Low Dose ◽  
Cell Function ◽  
Cytotoxic T Cells ◽  
Cytotoxic T Cell ◽  
Effector Cells ◽  
Cell Functions

Clinical immunotherapy trials like dendritic cell-based vaccinations are hampered by the tumor's offensive repertoire that suppresses the incoming effector cells. Regulatory T cells are instrumental in suppressing the function of cytotoxic T cells. We studied the effect of low-dose cyclophosphamide on the suppressive function of regulatory T cells and investigated if the success rate of dendritic cell immunotherapy could be improved. For this, mesothelioma tumor-bearing mice were treated with dendritic cell-based immunotherapy alone or in combination with low-dose of cyclophosphamide. Proportions of regulatory T cells and the cytotoxic T cell functions at different stages of disease were analyzed. We found that low-dose cyclophosphamide induced beneficial immunomodulatory effects by preventing the induction of Tregs, and as a consequence, cytotoxic T cell function was no longer affected. Addition of cyclophosphamide improved immunotherapy leading to an increased median and overall survival. Future studies are needed to address the usefulness of this combination treatment for mesothelioma patients.

scholarly journals TNF-α Regulates Mast Cell Functions by Inhibiting Cell Degranulation

2017 ◽  
Vol 44 (2) ◽  
pp. 751-762 ◽  
Author(s):  
Yuwei Gao ◽  
Baixue Xu ◽  
Peng Zhang ◽  
Yanlong He ◽  
Xin Liang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mast Cells ◽  
Cd4 T Cells ◽  
Cell Function ◽  
Mapk Signaling ◽  
Cell Functions ◽  
Tnf Α ◽  
Ifn Γ ◽  
Stimulation Of

Background/Aims: The aim of this study was to investigate the involvement of inducible co-stimulatory ligand (ICOSL) expression in stimulation of mast cells (MCs) by TNF-α and the ability of TNF-α stimulation of MCs to influence CD4+ T cell differentiation and function. The mechanisms underlying TNF-α stimulation of MCs were also explored. Methods: Mast cells and CD4+ T cells were prepared from C57BL/6 mice (aged 6–8 weeks). ICOSL expression by MCs was measured by real-time PCR and flow cytometry, and levels of IL-4, IL-10 and IFN-γ were measured by ELISA. Results: ICOSL expression by MCs was increased by TNF-α stimulation, and resulted in interaction with CD4+ T cells. The IL-4 and IL-10 levels in the co-culture system increased, while IFN-γ levels decreased. Furthermore, CD4+CD25+Foxp3+ T cell proliferation was induced by co-culture with TNF-α-stimulated MCs. The mechanism by which TNF-α stimulated MCs was dependent on the activation of the MAPK signaling pathway. Conclusion: TNF-α upregulated the expression of ICOSL on mast cells via a mechanism that is dependent on MAPK phosphorylation. TNF-α-treated MCs promoted the differentiation of regulatory T cells and induced a shift in cytokine expression from a Th1 to a Th2 profile by up-regulation ICOSL expression and inhibition of MC degranulation. Our study reveals a novel mechanism by which mast cells regulate T cell function.

scholarly journals Specificity of cytotoxicity T cells directed to influenza virus hemagglutinin.

1979 ◽  
Vol 149 (4) ◽  
pp. 856-869 ◽  
Author(s):  
T J Braciale
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
Type A ◽  
Cross Reactivity ◽  
Cytotoxic T Cell ◽  
Target Cells ◽  
Effector Cells ◽  
Cell Induction

Purified type A influenza viral hemagglutinin stimulates an in vitro cell-mediated cytotoxic cell response that exhibits a high degree of specificity for the immunizing hemagglutinin. The response magnitude is proportional to the hemagglutinin dose used for stimulation. The lytic activity of the effector cells is H-2 restricted. Analysis of the specificity of the response indicated that these cytotoxic T cells readily distinguish target cells expressing serologically unrelated hemagglutinin from target cells bearing hemagglutinins serologically related to the stimulating hemagglutinin. Further analysis of the fine specificity of cytotoxic T-cell recognition with serologically cross-reactive type A influenza hemagglutinins revealed a hierarchy of cross-reactivity among these hemagglutinins that was the converse of the serologic hierarchy. These results are discussed in terms of possible differences and similarities in the specificity repertoire of cytotoxic T cells and antibodies. Possible implications of these findings from the standpoint of cytotoxic T-cell induction are also discussed.

scholarly journals CD73 Ectonucleotidase Restrains CD8+ T Cell Metabolic Fitness and Anti-tumoral Activity

2021 ◽  
Vol 9 ◽  
Author(s):  
Pedro Briceño ◽  
Elizabeth Rivas-Yañez ◽  
Mariana V. Rosemblatt ◽  
Brian Parra-Tello ◽  
Paula Farías ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cytotoxic T Cells ◽  
Cd8 T Cell ◽  
Tumor Burden ◽  
Effector Cells ◽  
Cd73 Expression ◽  
Metabolic Fitness

CD39 and CD73 are ectoenzymes that dephosphorylate ATP into its metabolites; ADP, AMP, and adenosine, and thus are considered instrumental in the development of immunosuppressive microenvironments. We have previously shown that within the CD8+ T cell population, naïve and memory cells express the CD73 ectonucleotidase, while terminally differentiated effector cells are devoid of this enzyme. This evidence suggests that adenosine might exert an autocrine effect on CD8+ T cells during T cell differentiation. To study the possible role of CD73 and adenosine during this process, we compared the expression of the adenosinergic signaling components, the phenotype, and the functional properties between CD73-deficient and WT CD8+ T cells. Upon activation, we observed an upregulation of CD73 expression in CD8+ T cells along with an upregulation of the adenosine A2A receptor. Interestingly, when we differentiated CD8+ T cells to Tc1 cells in vitro, we observed that these cells produce adenosine and that CD73-deficient cells present a higher cytotoxic potential evidenced by an increase in IFN-γ, TNF-α, and granzyme B production. Moreover, CD73-deficient cells presented a increased glucose uptake and higher mitochondrial respiration, indicating that this ectonucleotidase restrict the mitochondrial capacity in CD8+ T cells. In agreement, when adoptively transferred, antigen-specific CD73-deficient CD8+ T cells were more effective in reducing the tumor burden in B16.OVA melanoma-bearing mice and presented lower levels of exhaustion markers than wild type cells. All these data suggest an autocrine effect of CD73-mediated adenosine production, limiting differentiation and cytotoxic T cells’ metabolic fitness.

scholarly journals Genetic models reveal origin, persistence and non-redundant functions of IL-17–producing γδ T cells

2018 ◽  
Vol 215 (12) ◽  
pp. 3006-3018 ◽  
Author(s):  
Inga Sandrock ◽  
Annika Reinhardt ◽  
Sarina Ravens ◽  
Christoph Binz ◽  
Anneke Wilharm ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Diphtheria Toxin ◽  
Γδ T Cells ◽  
Γδ T Cell ◽  
Fetal Thymus ◽  
Effector Cells ◽  
Cell Functions ◽  
Ifn Γ ◽  
Redundant Functions

γδ T cells are highly conserved in jawed vertebrates, suggesting an essential role in the immune system. However, γδ T cell–deficient Tcrd−/− mice display surprisingly mild phenotypes. We hypothesized that the lack of γδ T cells in constitutive Tcrd−/− mice is functionally compensated by other lymphocytes taking over genuine γδ T cell functions. To test this, we generated a knock-in model for diphtheria toxin–mediated conditional γδ T cell depletion. In contrast to IFN-γ–producing γδ T cells, IL-17–producing γδ T cells (Tγδ17 cells) recovered inefficiently after depletion, and their niches were filled by expanding Th17 cells and ILC3s. Complementary genetic fate mapping further demonstrated that Tγδ17 cells are long-lived and persisting lymphocytes. Investigating the function of γδ T cells, conditional depletion but not constitutive deficiency protected from imiquimod-induced psoriasis. Together, we clarify that fetal thymus-derived Tγδ17 cells are nonredundant local effector cells in IL-17–driven skin pathology.

scholarly journals Expression of T-cell differentiation antigens on effector cells in cell-mediated cytotoxicity in vitro. Evidence for functional heterogeneity related to the surface phenotype of T cells.

1975 ◽  
Vol 141 (1) ◽  
pp. 227-241 ◽  
Author(s):  
H Shiku ◽  
P Kisielow ◽  
M A Bean ◽  
T Takahashi ◽  
E A Boyse ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Killer Cell ◽  
Surface Antigens ◽  
Cell Phenotype ◽  
Direct Function ◽  
Effector Cells ◽  
Cell Functions ◽  
T Cell Antigens

The cell-mediated cytotoxicity (CMC) of nonadherent cells from the peritoneal cavity (NAPC) of alloimmunized mice can be measured by the [3H]proline microassay. The exhibition of thymus-derived (T) cell antigens on these killer cells was studied by incubating them with the relevant T-cell antisera and complement (C), under optimal conditions for lysis, before performance of the CMC assay. Under these conditions, the following T-cell antigens were demonstrable on the killer population in terms of percent reduction in CMC by the respective antisera: (a) Thy-1.1 (83%) and Thy-1.2 (100%), (b) MSLA (86%), (c) NTA-RA (a T-cell antigen recognized by naturally occurring autoantibody of NZB mice) (62%), (d) Ly1.1 )58%, (e) Ly-2.1 (11%; considered a marginal result) and Ly-2.2 (63%), and (f) Ly-3.2 (77%). The following were not demonstrable: (g) TL, and (h) Ly-1.2. (i) The antigen Ly-3.1 was not studied. Omission of C deprived all T-cell antisera tested of their capacity to suppress CMC, indicating that the cell components recognized by such antisera may perform no direct function in CMC. On the assumption that all Ly+ cells are Thy-1+, it is clear that the T-cell members of the immune NAPC population must be heterogenous. This follows from the fact that the proportions of T cells lysed by different Ly antisera did not correspond with ensuing degree of loss of CMC capacity. The extremes were represented by anti-Ly-1.2 (74% Thy-1+ cells lysed, but no reduction in CMC) and Ly-3.2 (54% Thy-1+ cells lysed, with 77% reduction in CMC). From this initial survey it appears that the C57BL/6 mice killer T-cell population active in CMC in vitro is relatively rich in surface antigens of the Ly-2/Ly-3 category and relatively poor in representation of the Ly-1 surface antigens. It remains to be seen whether this killer cell phenotype, poor in Ly-1 and rich in Ly-2/Ly-3, is characteristic of the mouse generally. From these results it appears that subsets of T cells with different immunological functions may exhibit qualitative or quantitative differences in surface antigens specified by different Ly loci; this will be easier to assess in the future when the results of experiments with the same Ly antisera but dealing with T-cell functions other than CMC become available.

scholarly journals B7 and interleukin 12 cooperate for proliferation and interferon gamma production by mouse T helper clones that are unresponsive to B7 costimulation.

1994 ◽  
Vol 180 (1) ◽  
pp. 223-231 ◽  
Author(s):  
E E Murphy ◽  
G Terres ◽  
S E Macatonia ◽  
C S Hsieh ◽  
J Mattson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Interleukin 12 ◽  
T Helper ◽  
Ifn Gamma ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Maximal Stimulation ◽  
Costimulatory Signals ◽  
Stimulation Of

We have previously shown that dendritic cells isolated after overnight culture, which can express B7 and are potent stimulators of naive T cell proliferation, are relatively poor at inducing the proliferation of a panel of murine T helper 1 (Th1) clones. Maximal stimulation of Th1 clones was achieved using unseparated splenic antigen presenting cells (APC). An explanation for these findings is provided in the present study where we show that FcR+ L cells transfected with B7 stimulate minimal proliferation of Th1 clones in response to anti-CD3 antibodies, in contrast to induction of significant proliferation of naive T cells. However, addition of interleukin 12 (IL-12) to cultures of Th1 cells stimulated with anti-CD3 and FcR+ B7 transfectants resulted in a very pronounced increase in proliferation and interferon gamma (IFN-gamma) production. Exogenous IL-12 did not affect the B7-induced proliferation of naive T cells. This showed that whereas costimulatory signals delivered via B7-CD28 interaction are sufficient to induce significant proliferation of naive T cells activated through occupancy of the T cell receptor, Th1 T cell clones require cooperative costimulation by B7 and IL-12. This costimulation was shown to be specific by inhibition of proliferation and IFN-gamma production using chimeric soluble cytolytic T lymphocyte-associated antigen 4-human IgG1Fc (CTLA4-Ig) and anti-IL-12 antibodies. Furthermore, the significant antigen specific proliferation and IFN-gamma production by Th1 clones observed when splenocytes were used as APC was almost completely abrogated using CTLA4-Ig and anti-IL-12 antibodies. Thus two costimulatory signals, B7 and IL-12, account for the ability of splenic APC to induce maximal stimulation of Th1 clones. IL-10 downregulates the expression of IL-12 by IFN-gamma-stimulated macrophages and this may account largely for t the ability of IL-10 to inhibit APC function of splenic and macrophage APC for the induction of Th1 cell proliferation and IFN-gamma production. Indeed we show that IL-12 can overcome the inhibitory effect of IL-10 for the APC-dependent induction of proliferation and IFN-gamma production by Th1 clones. These results suggest that proliferation by terminally differentiated Th1 clones, in contrast to naive T cells, requires stimulation via membrane-bound B7 and a cytokine, IL-12. It is possible that these signals may result in the activation of unresponsive T cells during an inflammatory response. IL-10, by its role in regulating such innate inflammatory responses, may thus help to maintain these T cells in an unresponsive state.

scholarly journals Regulation of T Cells in Cancer by Nitric Oxide

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2655
Author(s):  
Inesa Navasardyan ◽  
Benjamin Bonavida
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Suppressor Cells ◽  
T Cell Response ◽  
T Cell Subsets ◽  
Target Cells ◽  
Effector Cells ◽  
Cell Functions

The T cell-mediated immune response is primarily involved in the fight against infectious diseases and cancer and its underlying mechanisms are complex. The anti-tumor T cell response is regulated by various T cell subsets and other cells and tissues in the tumor microenvironment (TME). Various mechanisms are involved in the regulation of these various effector cells. One mechanism is the iNOS/.NO that has been reported to be intimately involved in the regulation and differentiation of the various cells that regulate the anti-tumor CD8 T cells. Both endogenous and exogenous .NO are implicated in this regulation. Importantly, the exposure of T cells to .NO had different effects on the immune response, depending on the .NO concentration and time of exposure. For instance, iNOS in T cells regulates activation-induced cell death and inhibits Treg induction. Effector CD8 T cells exposed to .NO result in the upregulation of death receptors and enhance their anti-tumor cytotoxic activity. .NO-Tregs suppress CD4 Th17 cells and their differentiation. Myeloid-derived suppressor cells (MDSCs) expressing iNOS inhibit T cell functions via .NO and inhibit anti-tumor CD8 T cells. Therefore, both .NO donors and .NO inhibitors are potential therapeutics tailored to specific target cells that regulate the T cell effector anti-tumor response.

Cotransfection of Dendritic Cells with RNA Coding for a Tumor Antigen and Costimulatory Molecule 4-1BBL Increases the Induction of Her-2/neu Specific Cytotoxic T-Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1352-1352
Author(s):  
Frank Grünebach ◽  
Katrin Kayser ◽  
Silke Appel ◽  
Markus M. Weck ◽  
Martin R. Müller ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cell Line ◽  
Cytotoxic T Cells ◽  
Specific Lysis ◽  
Stimulatory Capacity ◽  
Her 2 ◽  
Stimulation Of

Abstract Dendritic cells are professional antigen-presenting cells (APC) with the unique capacity to initiate primary immune responses. Recently, it was demonstrated that transfection of DC with RNA coding for specific antigens can elicit an effective T cell response in vitro and in vivo. 4-1BB (CD137) is a member of a family of receptors found on the surface of cells of the immune system. It plays an important role in the costimulation of T-cells: it enhances T-cell proliferation, cytokine production and cytotoxic effector functions and suppresses the induction of apoptosis. It is predominantly expressed on activated T-cells, and its ligand 4-1BBL is expressed on activated APC including DC. In the present study we analyzed the effects of 4-1BBL on the stimulatory capacity of DC. Monocyte derived DC were electroporated with in vitro transcribed RNA encoding the tumor-associated antigen Her-2/neu. Additionally these cells were cotransfected with in vitro transcribed RNA coding for the human 4-1BBL with the aim to enhance the costimulatory functions of the cells and therefore the induction of Her-2/neu specific cytotoxic T-cells (CTL). Standard 51Cr-release assays performed after two restimulations showed specific cytotoxic activity of the induced CTL against autologous DC transfected with Her-2/neu RNA and against the HLA-matched allogeneic Her-2/neu+/HLA-A2+ renal cell carcinoma cell line A498 whereas DC transfected with irrelevant RNA as well as Her-2/neu-/HLA-A2+ CROFT cells and the Her-2/neu+/HLA-A2- cell line SK-OV-3 were spared. There was no lysis of K562 cells, thus excluding a NK-cell mediated killing. In this experimental setting the specific lysis rate of target cells could nearly be doubled by the coadministration of Her-2/neu RNA and an equal amount of 4-1BBL RNA (50% vs 90% specific lysis at effector to target ratio of 30:1). Interestingly, overexpression of 4-1BBL had no effect on the stimulation of allogeneic T cells by electroporated DC in a mixed lymphocyte reaction, indicating that 4-1BBL increases the induction of antigen specific T cell responses rather than the unspecific stimulation of bulk T lymphocytes. Furthermore, FACS analysis of DC transfected with 4-1BBL plasmid DNA or in vitro transcribed 4-1BBL RNA showed higher expression of the costimulatory molecules CD80, CD86, CD40 and the T-cell adhesion molecule CD54 as compared to the controls indicating that 4-1BBL signaling can mediate activation of DC and thus increase their stimulatory capacity. In the context of immunotherapies for cancer patients the findings of our study could contribute to optimise the in vitro manipulation of DC for the induction of antigen-specific CTL responses.

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