scholarly journals CTLA-4 is a second receptor for the B cell activation antigen B7.

1991 ◽  
Vol 174 (3) ◽  
pp. 561-569 ◽  
Author(s):  
P S Linsley ◽  
W Brady ◽  
M Urnes ◽  
L S Grosmaire ◽  
N K Damle ◽  
...  
Keyword(s):  
Fusion Protein ◽  
B Lymphocytes ◽  
Functional Properties ◽  
Cell Activation ◽  
Chinese Hamster Ovary Cells ◽  
Interleukin 2 ◽  
Chinese Hamster ◽  
T And B Lymphocytes ◽  
Cellular Interactions

Functional interactions between T and B lymphocytes are necessary for optimal activation of an immune response. Recently, the T lymphocyte receptor CD28 was shown to bind the B7 counter-receptor on activated B lymphocytes, and subsequently to costimulate interleukin 2 production and T cell proliferation. CTLA-4 is a predicted membrane receptor from cytotoxic T cells that is homologous to CD28 and whose gene maps to the same chromosomal band as the gene for CD28. It is not known, however, if CD28 and CTLA-4 also share functional properties. To investigate functional properties of CTLA-4, we have produced a soluble genetic fusion between the extracellular domain of CTLA-4 and an immunoglobulin C gamma chain. Here, we show that the fusion protein encoded by this construct, CTLA4Ig, bound specifically to B7-transfected Chinese hamster ovary cells and to lymphoblastoid cells. CTLA4Ig also immunoprecipitated B7 from cell surface 125I-labeled extracts of these cells. The avidity of 125I-labeled B7Ig fusion protein for immobilized CTLA4Ig was estimated (Kd approximately 12 nM). Finally, we show that CTLA4Ig was a potent inhibitor of in vitro immune responses dependent upon cellular interactions between T and B lymphocytes. These findings provide direct evidence that, like its structural homologue CD28, CTLA-4 is able to bind the B7 counter-receptor on activated B cells. Lymphocyte interactions involving the B7 counter-receptor are functionally important for alloantigen responses in vitro.

scholarly journals In vitro co-stimulation of anti-tumor activity by soluble B7 molecules.

2006 ◽  
Vol 53 (4) ◽  
pp. 807-813 ◽  
Author(s):  
Wei He ◽  
Zhong-Bo Hu ◽  
Fang Liu ◽  
Xian-Qi Feng ◽  
Ping Zou
Keyword(s):  
Fusion Protein ◽  
T Cell Activation ◽  
Immune Escape ◽  
Chinese Hamster Ovary Cells ◽  
Interleukin 2 ◽  
Leukemia Cell ◽  
Chinese Hamster ◽  
Leukemia Cell Line ◽  
Anti Tumor Activity

In order to investigate the anti-tumor activity of a soluble B7-1/immunoglobulin G fusion protein and explore an effective method to eliminate immune escape of tumor cells, a recombinant vector encoding this fusion protein was constructed and constitutively expressed in Chinese hamster ovary cells. After purification with protein G affinity chromatography, the soluble fusion protein was tested for bioactivity. Results showed that the fusion protein could significantly increase the density of B7-1 molecules on WEHI-3 cells, a mouse leukemia cell line. Through allogeneic mixed lymphocyte tumor cultures, it was demonstrated that, with the presence of the first signal, it could also significantly enhance T cell activation and killing activity against WEHI-3 cells and interleukin-2 secretion by activated mouse T lymphocytes. The conclusion can be drawn that the soluble B7-IgG fusion protein has a potent capacity to generate or enhance anti-tumor immune response in vitro, and its clinical value deserves further investigation.

Design, Synthesis, Molecular Docking and Biological Evaluation of 1-(benzo[d]thiazol-2-ylamino)(phenyl)methyl)naphthalen-2-ol Derivatives as Antiproliferative Agents

2019 ◽  
Vol 16 (10) ◽  
pp. 837-845
Author(s):  
Sandhya Jonnala ◽  
Bhaskar Nameta ◽  
Murthy Chavali ◽  
Rajashaker Bantu ◽  
Pallavi Choudante ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Inhibitory Activity ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Mouse Skin ◽  
Coupling Reaction ◽  
Binding Mode ◽  
Biological Evaluation ◽  
Design Synthesis

A class of 1-((benzo[d]thiazol-2-ylamino)(phenyl)methyl)naphthalen-2-ol derivatives (4a-t) has been synthesized in good yields through a three component coupling reaction. The newly synthesized compounds were evaluated for their in vitro antiproliferative activity against five cell lines such as DU145 (human prostate cancer), MDA-MB-B231 (human breast cancer), SKOV3 (human ovarian cancer), B16-F10 (mouse skin melanoma) and CHO-K1 (Chinese hamster ovary cells), a noncancerous cell line. In vitro inhibitory activity indicates that compounds 4a, 4b, 4c, 4d, 4g, 4j, and 4o exhibited potent anti-proliferative behavior. Among them, compounds 4g, 4j and 4o found to be the most active members exhibiting remarkable growth inhibitory activity. Molecular docking facilitates to investigate the probable binding mode and key active site interactions in tubulins α and β proteins. The docking results are complementary to experimental results.

scholarly journals AB0024 IN VITRO CHARACTERIZATION OF CENERIMOD, A POTENT AND SELECTIVE SPHINGOSINE 1-PHOSPHATE RECEPTOR 1 (S1P1) MODULATOR IN PREVENTING MIGRATION OF NON-ACTIVATED AND ACTIVATED PRIMARY HUMAN B CELLS IN THE PRESENCE OR ABSENCE OF GLUCOCORTICOIDS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1046.1-1046
Author(s):  
L. Schlicher ◽  
P. Kulig ◽  
M. Murphy ◽  
M. Keller
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Cell Activation ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
B Cell Activation ◽  
Human B Cells ◽  
Circulating Lymphocytes

Background:Cenerimod is a potent, selective, and orally active sphingosine 1-phosphate receptor 1 (S1P1) modulator that is currently being evaluated in a Phase 2b study in patients with systemic lupus erythematosus (SLE) (NCT03742037). S1P1 receptor modulators sequester circulating lymphocytes within lymph nodes, thereby reducing pathogenic autoimmune cells (including B lymphocytes) in the blood stream and in inflamed tissues. Extensive clinical experience has become available for the nonselective S1P receptor modulator fingolimod in relapsing forms of multiple sclerosis, supporting this therapeutic concept for the treatment of autoimmune disorders.Objectives:Although the effect of S1P-receptor modulators in reducing peripheral B cells is well documented1,2, the role of the S1P1 receptor on this cell type is only incompletely understood. In this study, the mode of action of cenerimod on primary human B cells was investigated in a series of in vitro experiments, including S1P1 receptor cell surface expression and chemotaxis towards S1P. Moreover, S1P1 expression following B cell activation in vitro was studied. As glucocorticoids (GC) are frequently used in the treatment of patients with autoimmune disorders including SLE, the potential influence of GC on the mode of action of cenerimod was evaluated.Methods:Primary human B lymphocytes from healthy donors were isolated from whole blood. In one set of experiments, cells were treated with different concentrations of cenerimod to measure S1P1 receptor internalization by flow cytometry. In a second set of experiments, isolated B cells were activated using different stimuli or left untreated. Cells were then analysed for S1P1 and CD69 cell surface expression and tested in a novel real-time S1P-mediated migration assay. In addition, the effect of physiological concentrations of GCs (prednisolone and prednisone) on cenerimod activity in preventing S1P mediated migration was tested.Results:In vitro, cenerimod led to a dose-dependent internalization of the S1P1 receptor on primary human B lymphocytes. Cenerimod also blocked migration of nonactivated and activated B lymphocytes towards S1P in a concentration-dependent manner, which is in line with the retention of lymphocytes in the lymph node and the reduction of circulating lymphocytes observed in the clinical setting. Upon B cell activation, which was monitored by CD69 upregulation, a simultaneous downregulation of S1P1 expression was detected, leading to less efficient S1P-directed cell migration. Importantly, physiological concentrations of GC did not affect the inhibitory activity of cenerimod on B cell migration.Conclusion:These results show that cenerimod, by modulating S1P1, blocks B lymphocyte migration towards its natural chemoattractant S1P and demonstrate compatibility of cenerimod with GC. These results are consistent with results of comparable experiments done previously using primary human T lymphocytes.References:[1]Nakamura M et al., Mult Scler. 2014 Sep; 20(10):1371-80.[2]Strasser DS et al., RMD Open 2020;6:e001261.Disclosure of Interests:None declared

scholarly journals Expression of Human Interleukin-2 in Recombinant Baby Hamster Kidney, Ltk−, and Chinese Hamster Ovary Cells

1989 ◽  
Vol 264 (29) ◽  
pp. 17368-17373
Author(s):  
H S Conradt ◽  
M Nimtz ◽  
K E J Dittmar ◽  
W Lindenmaier ◽  
J Hoppe ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Interleukin 2 ◽  
Chinese Hamster ◽  
Baby Hamster Kidney ◽  
Ovary Cells

scholarly journals In Vitro Cytotoxic Activity Guided Essential Oil Composition of Flowering Twigs of Stevia rebaudiana

2014 ◽  
Vol 9 (5) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Tavleen S Mann ◽  
Vijai K Agnihotri ◽  
Dharmesh Kumar ◽  
Probir K Pal ◽  
Rajkesh Koundal ◽  
...  
Keyword(s):  
Essential Oil ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Complex Mixture ◽  
Stevia Rebaudiana ◽  
Spectroscopic Techniques ◽  
Oil Composition ◽  
Standard Drug ◽  
Rat Glioma

The essential oil extracted by hydrodistillation from the flowering twigs of Stevia rebaudiana Bertoni (Asteraceae) was fractioned by chromatography. Forty-three constituents were characterized with the help of GC, GC-MS and other spectroscopic techniques. The essential oil was found to be a complex mixture of mono- and sesqui-terpenes. The cytotoxicity of the essential oil and its fractions was evaluated by sulforhodamine B (SRB) based assay against two cancer cell types viz. C-6 (rat glioma cells) and CHOK1 (Chinese hamster ovary cells). The essential oil and its fractions showed promising cytotoxicity against both cell lines. The highest activity (95.6±0.6%) was show by the essential oil on the C-6 cell line at a concentration of 400 μg/mL, which was comparable with that of the standard drug vinblastin.

scholarly journals Evaluation of Fab and F(ab′)2 Fragments and Isotype Variants of a Recombinant Human Monoclonal Antibody against Shiga Toxin 2

2010 ◽  
Vol 78 (3) ◽  
pp. 1376-1382 ◽  
Author(s):  
Donna E. Akiyoshi ◽  
Abhineet S. Sheoran ◽  
Curtis M. Rich ◽  
L. Richard ◽  
Susan Chapman-Bonofiglio ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Shiga Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Human Monoclonal Antibody ◽  
Chinese Hamster ◽  
The Body ◽  
Neutralization Activity ◽  
Shiga Toxin 2

ABSTRACT 5C12 HuMAb is a human monoclonal antibody against the A subunit of Shiga toxin 2 (Stx2). We have previously shown that 5C12 HuMAb effectively neutralizes the cytotoxic effects of this toxin by redirecting its transport within the cell and also by neutralizing the toxin's ability to inhibit protein synthesis. The 5C12 HuMAb and its recombinant IgG1 version protect mice at a dose of 0.6 μg against a lethal challenge of Stx2. The contribution of the Fc region to this observed neutralization activity of the 5C12 antibody against Stx2 was investigated in this study. Using recombinant DNA technology, 5C12 isotype variants (IgG1, IgG2, IgG3, and IgG4) and antibody fragments [Fab, F(ab′)2] were expressed in Chinese hamster ovary cells and evaluated in vitro and in vivo. All four 5C12 isotype variants showed protection in vitro, with the IgG3 and IgG4 variants showing the highest protection in vivo. The Fab and F(ab′)2 fragments also showed protection in vitro but no protection in the mouse toxicity model. Similar results were obtained for a second HuMAb (5H8) against the B subunit of Stx2. The data suggest the importance of the Fc region for neutralization activity, but it is not clear if this is related to the stability of the full-length antibody or if the Fc region is required for effective elimination of the toxin from the body.

scholarly journals Peptide Antagonists That Inhibit Sin Nombre Virus and Hantaan Virus Entry through the β3-Integrin Receptor

2005 ◽  
Vol 79 (12) ◽  
pp. 7319-7326 ◽  
Author(s):  
Richard S. Larson ◽  
David C. Brown ◽  
Chunyan Ye ◽  
Brian Hjelle
Keyword(s):  
Viral Entry ◽  
Sequence Similarity ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Phage Display Library ◽  
Hantaan Virus ◽  
Sin Nombre Virus ◽  
Fab Fragment ◽  
Ovary Cells

ABSTRACT Specific therapy is not available for the treatment of hantavirus cardiopulmonary syndrome caused by Sin Nombre virus (SNV). The entry of pathogenic hantaviruses into susceptible human cells is dependent upon expression of the αvβ3 integrin, and transfection of human β3 integrin is sufficient to confer infectibility onto CHO (Chinese hamster ovary) cells. Furthermore, pretreatment of susceptible cells with anti-β3 antibodies such as c7E3 or its Fab fragment ReoPro prevents hantavirus entry. By using repeated selection of a cyclic nonamer peptide phage display library on purified αvβ3, we identified 70 peptides that were competitively eluted with ReoPro. Each of these peptides was examined for its ability to reduce the number of foci of SNV strain SN77734 in a fluorescence-based focus reduction assay according to the method of Gavrilovskaya et al. (I. N. Gavrilovskaya, M. Shepley, R. Shaw, M. H. Ginsberg, and E. R. Mackow, Proc. Natl. Acad. Sci. USA 95:7074-7079, 1998). We found that 11 peptides reduced the number of foci to a greater extent than did 80 μg/ml ReoPro when preincubated with Vero E6 cells. In addition, 8 of the 70 peptides had sequence similarity to SNV glycoproteins. We compared all 18 peptide sequences (10 most potent, 7 peptides with sequence similarity to hantavirus glycoproteins, and 1 peptide that was in the group that displayed the greatest potency and had significant sequence similarity) for their abilities to inhibit SNV, Hantaan virus (HTNV), and Prospect Hill virus (PHV) infection. There was a marked trend for the peptides to inhibit SNV and HTNV to a greater extent than they inhibited PHV, a finding that supports the contention that SNV and HTNV use β3 integrins and PHV uses a different receptor, β1 integrin. We then chemically synthesized the four peptides that showed the greatest ability to neutralize SNV. These peptides inhibited viral entry in vitro as free peptides outside of the context of a phage. Some combinations of peptides proved more inhibitory than did individual peptides. In all, we have identified novel peptides that inhibit entry by SNV and HTNV via β3 integrins and that can be used as lead compounds for further structural optimization and consequent enhancement of activity.

scholarly journals Hipotiroidismo Associado a Anticorpos Anti-Receptor da Hormona TSH com Ação Bloqueadora Determinada In Vitro

2015 ◽  
Vol 28 (5) ◽  
pp. 663
Author(s):  
Pedro Marques ◽  
Karim Chikh ◽  
Anne Charrié ◽  
Rosa Pina ◽  
Maria João Bugalho ◽  
...  
Keyword(s):  
Hormone Receptor ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Thyroid Stimulating Hormone ◽  
Human Thyroid ◽  
In Vitro Tests ◽  
Lymphocytic Thyroiditis ◽  
Blocking Activity ◽  
Stimulating Hormone

Thyroid-stimulating hormone-receptor autoantibodies normally causes hyperthyroidism. However, they might have blocking activity causing hypothyroidism. A 11-year-old girl followed due to type 1 diabetes mellitus, celiac disease and euthyroid lymphocytic thyroiditis at diagnosis. Two years after the initial evaluation, thyroid-stimulating hormone was suppressed with normal free T4; nine months later, a biochemical evolution to hypothyroidism with thyroid-stimulating hormone-receptor autoantibodies elevation was seen; the patient remained always asymptomatic. Chinese hamster ovary cells were transfected with the recombinant human thyroid-stimulating hormone -receptor, and then exposed to the patient´s serum; it was estimated a ‘moderate’ blocking activity of these thyroid-stimulating hormone-receptor autoantibodies, and concomitantly excluded stimulating action. In this case, the acknowledgment of the blocking activity of the serum thyroid-stimulating hormone-receptor autoantibodies, supported the hypothesis of a multifactorial aetiology of the hypothyroidism, which in the absence of the in vitro tests, we would consider only as a consequence of the destructive process associated to lymphocytic thyroiditis.

scholarly journals In Vivo Role of Dendritic Cells in a Murine Model of Pulmonary Cryptococcosis

2006 ◽  
Vol 74 (7) ◽  
pp. 3817-3824 ◽  
Author(s):  
Karen L. Wozniak ◽  
Jatin M. Vyas ◽  
Stuart M. Levitz
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Ex Vivo ◽  
Interleukin 2 ◽  
Mouse Lung

ABSTRACT Dendritic cells (DC) have been shown to phagocytose and kill Cryptococcus neoformans in vitro and are believed to be important for inducing protective immunity against this organism. Exposure to C. neoformans occurs mainly by inhalation, and in this study we examined the in vivo interactions of C. neoformans with DC in the lung. Fluorescently labeled live C. neoformans and heat-killed C. neoformans were administered intranasally to C57BL/6 mice. At specific times postinoculation, mice were sacrificed, and lungs were removed. Single-cell suspensions of lung cells were prepared, stained, and analyzed by microscopy and flow cytometry. Within 2 h postinoculation, fluorescently labeled C. neoformans had been internalized by DC, macrophages, and neutrophils in the mouse lung. Additionally, lung DC from mice infected for 7 days showed increased expression of the maturation markers CD80, CD86, and major histocompatibility complex class II. Finally, ex vivo incubation of lung DC from infected mice with Cryptococcus-specific T cells resulted in increased interleukin-2 production compared to the production by DC from naïve mice, suggesting that there was antigen-specific T-cell activation. This study demonstrated that DC in the lung are capable of phagocytosing Cryptococcus in vivo and presenting antigen to C. neoformans-specific T cells ex vivo, suggesting that these cells have roles in innate and adaptive pulmonary defenses against cryptococcosis.

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