Evaluation of the T Cell Workshop Monoclonal Antibodies in In Vitro Lymphocyte Proliferation Assays

1986 ◽  
pp. 173-187
Author(s):  
Nicolas L. von Jeney ◽  
Katja Olas ◽  
Walter Knapp
Keyword(s):  
Monoclonal Antibodies ◽  
T Cell ◽  
Lymphocyte Proliferation ◽  
Proliferation Assays

T-Cell Activation by Bispecific Monoclonal Antibodies for Lysis of Renal Cell Carcinoma In Vitro

1992 ◽  
pp. 156-161
Author(s):  
J. van Dijk ◽  
S. Th. Zegveld ◽  
J. D. H. van Eendenburg ◽  
E. Braakman ◽  
G. J. Fleuren ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
Cell Carcinoma ◽  
T Cell Activation ◽  
Renal Cell ◽  
Cell Activation

Bovine Chromaffin Cells for CNS Transplantation do not Elicit Xenogeneic T Cell Proliferative Responses in Vitro

1996 ◽  
Vol 5 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Kimberly A. Czech ◽  
Raymond Pollak ◽  
George D. Pappas ◽  
Jacqueline Sagen
Keyword(s):  
Endothelial Cells ◽  
T Cell ◽  
Adrenal Medulla ◽  
Lymphocyte Proliferation ◽  
Chromaffin Cells ◽  
Positive Control ◽  
Rat Lymphocytes ◽  
Bovine Chromaffin Cells ◽  
Adrenal Chromaffin

Adrenal chromaffin cells have been utilized for several neural grafting applications, but limitations in allogeneic donor availability and dangers inherent in auto-grafting limit the widespread use of this approach clinically. While xenogeneic donors offer promise as a source for cell transplantation in the central nervous system (CNS), immunologic responses to cellular components of the adrenal medulla have not been well characterized. To further study the host T cell xenogeneic response to chromaffin and passenger cells of the adrenal medulla, an in vitro lymphocyte proliferation assay was used. Lymphocyte proliferation was determined by mixing rat lymphocytes with potential stimulator cell subpopulations of the bovine adrenal medulla: isolated chromaffin cells, isolated endothelial cells, or passenger nonchromaffin cells, which include a mixture of fibroblasts, smooth muscle cells, and endothelial cells. As a positive control, bovine aortic endothelial cells were also used. 3[H]-thymidine incorporation, corresponding to lymphocyte proliferation, was measured. Results indicated that isolated bovine chromaffin cells produce only a mild, statistically insignificant stimulation of rat lymphocytes. In contrast, there was a significant response to passenger nonchromaffin cells of the adrenal medulla, especially endothelial cells. The inclusion of low levels of cyclosporin A in the cultures completely eliminated the mild proliferative response to isolated bovine chromaffin cells, while near toxic levels were necessary to abrogate the response to endothelial cells. Immunocytochemical analysis revealed that routine chromaffin cell isolation procedures result in the inclusion of a small percentage of endothelial cells, which may be responsible for the slight lymphocyte stimulation. The results of this study indicate that isolated chromaffin cells possess low immunogenicity, and suggest that passenger cells in the adrenal medulla, particularly endothelial cells, may be primarily responsible for progressive rejection in CNS grafts. Thus, removal of passenger nonchromaffin cells from xenogeneic donor tissues prior to transplantation may produce a more tolerated graft in rodent models of neural transplantation.

scholarly journals Aggregation of Human Recombinant Monoclonal Antibodies Influences the Capacity of Dendritic Cells to Stimulate Adaptive T-Cell Responses In Vitro

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e86322 ◽  
Author(s):  
Verena Rombach-Riegraf ◽  
Anette C. Karle ◽  
Babette Wolf ◽  
Laetitia Sordé ◽  
Stephan Koepke ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
T Cell Responses ◽  
Cell Responses

scholarly journals Reduced Neutralization of SARS-CoV-2 Omicron Variant by Vaccine Sera and monoclonal antibodies

2021 ◽  
Author(s):  
Alexander Wilhelm ◽  
Marek Widera ◽  
Katharina Grikscheit ◽  
Tuna Toptan ◽  
Barbara Schenk ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
T Cell ◽  
Spike Protein ◽  
Cell Mediated Immunity ◽  
Treatment Variant

AbstractDue to numerous mutations in the spike protein, the SARS-CoV-2 variant of concern Omicron (B.1.1.529) raises serious concerns since it may significantly limit the antibody-mediated neutralization and increase the risk of reinfections. While a rapid increase in the number of cases is being reported worldwide, until now there has been uncertainty about the efficacy of vaccinations and monoclonal antibodies. Our in vitro findings using authentic SARS-CoV-2 variants indicate that in contrast to the currently circulating Delta variant, the neutralization efficacy of vaccine-elicited sera against Omicron was severely reduced highlighting T-cell mediated immunity as essential barrier to prevent severe COVID-19. Since SARS-CoV-2 Omicron was resistant to casirivimab and imdevimab, genotyping of SARS-CoV-2 may be needed before initiating mAb treatment. Variant-specific vaccines and mAb agents may be required to treat COVID-19 due to Omicron and other emerging variants of concern.

scholarly journals Surfactant protein A inhibits T cell proliferation via its collagen-like tail and a 210-kDa receptor

1998 ◽  
Vol 275 (4) ◽  
pp. L679-L686 ◽  
Author(s):  
Paul Borron ◽  
Francis X. McCormack ◽  
Baher M. Elhalwagi ◽  
Zissis C. Chroneos ◽  
James F. Lewis ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cell ◽  
T Lymphocyte ◽  
Lymphocyte Proliferation ◽  
Pulmonary Surfactant ◽  
Protein A ◽  
T Cell Proliferation ◽  
T Lymphocyte Proliferation ◽  
Human T Lymphocyte

Investigation of possible mechanisms to describe the hyporesponsiveness of pulmonary leukocytes has led to the study of pulmonary surfactant and its constituents as immune suppressive agents. Pulmonary surfactant is a phospholipid-protein mixture that reduces surface tension in the lung and prevents collapse of the alveoli. The most abundant protein in this mixture is a hydrophilic molecule termed surfactant-associated protein A (SP-A). Previously, we showed that bovine (b) SP-A can inhibit human T lymphocyte proliferation and interleukin-2 production in vitro. Results presented in this investigation showed that different sources of human SP-A and bSP-A as well as recombinant rat SP-A inhibited human T lymphocyte proliferation in a dose-dependent manner. A structurally similar collagenous protein, C1q, did not block the in vitro inhibitory action of SP-A. The addition of large concentrations of mannan to SP-A-treated cultures also did not disrupt inhibition, suggesting that the effect is not mediated by the carbohydrate recognition domain of SP-A. Use of recombinant mutant SP-As revealed that a 36-amino acid Arg-Gly-Asp (RGD) motif-containing span of the collagen-like domain was responsible for the inhibition of T cell proliferation. A polyclonal antiserum directed against an SP-A receptor (SP-R210) completely blocked the inhibition of T cell proliferation by SP-A. These results emphasize a potential role for SP-A in dampening lymphocyte responses to exogenous stimuli. The data also provide further support for the concept that SP-A maintains a balance between the clearance of inhaled pathogens and protection against collateral immune-mediated damage.

BCX-4208 (RO5092888), a Purine Nucleoside Phosphorylase (PNP) Inhibitor, Is a Novel, Potent Orally Active Anti-T-Cell and B-Cell Agent.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1547-1547
Author(s):  
Shanta Bantia ◽  
Cynthia Parker ◽  
Ramanda Upshaw ◽  
John Michael Kilpatrick ◽  
Amanda Cunningham ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Lymphocyte Proliferation ◽  
Clinical Investigation ◽  
Human Lymphocytes ◽  
Annexin V ◽  
Fold Increase ◽  
Cell Immunity

Abstract The profound suppression of T-cell immunity seen in patients with an inherited PNP deficiency supports the potential application of inhibitors of this purine salvage enzyme in the therapy of T-cell malignancies and T-cell mediated autoimmune diseases. About thirty percent of PNP deficient patients also show evidence of B-cell dysfunction. BCX-4208 is a novel potent transition state analog inhibitor of PNP (IC50 ~ 0.0005 μM) and in the presence of 10 μM deoxyguanosine (dGuo), inhibits human lymphocyte proliferation induced by MLR, IL-2 or Con-A with IC50s of 0.159, 0.26 and 0.73 μM, respectively. The IC50 for dGuo in the same assays in the presence of 1 μM BCX-4208 ranges from 1–3 μM. Neither BCX-4208 alone nor dGuo alone inhibits proliferation of lymphocytes. In the presence of PNP inhibitor, dGuo is converted to dGMP and then to dGTP. Accumulation of dGTP results in the alteration of deoxynucleotide (dNTP) pools, causing death of cells via a mechanism characteristic of apoptosis. In vitro data demonstrates that following exposure to BCX-4208 and dGuo, dGTP in human lymphocytes is elevated and a 5–8 fold increase in dGTP results in 50% inhibition of lymphocyte proliferation. Flow cytometric analyses of human lymphocytes using annexin-V staining reveal that BCX-4208 in the presence of dGuo induces cellular apoptosis not only in T cells (CD3+), but also in B cells (CD20+; CD19+) (Table 1). BCX-4208 is orally bioavailable in mice, can achieve maximal inhibition of PNP, and elevates plasma dGuo levels to 3–5 μM (predose levels < 0.004 μM), which is similar to levels seen in PNP deficient patients and to levels needed to cause apoptosis in T and B-cells. These data support the evaluation of BCX-4208 in the treatment of not only T-cell mediated diseases but also B-cell mediated diseases. BCX- 4208 is currently undergoing early clinical investigation in patients with psoriasis. Table 1. Cell subsets % Apoptotic cells mean ± SEM (n = 4–7) Vehicle Treatment group *p ≤ 0.01 compared to vehicle CD3+ 7.2 ± 0.9 18.3 ± 3.7* CD20+ 24.0 ± 3.6 41.8 ± 6.2* CD19+ 25.0 ± 3.1 51.6 ± 7.4*

scholarly journals Multiplexed Engineered, Off-the-Shelf T Cells Carrying Three Tumor-Associated Antigen-Targeting Modalities: CAR + Pan-Tumor Targeting TCR + CD16 Fc Receptor

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 32-32
Author(s):  
Cokey Nguyen ◽  
Eigen Peralta ◽  
Chia-Wei Chang ◽  
Wen-I Yeh ◽  
Yijia Pan ◽  
...  
Keyword(s):  
T Cells ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
Tumor Heterogeneity ◽  
Tumor Antigens ◽  
Fc Receptor ◽  
Car T Cells ◽  
Tumor Associated Antigen ◽  
Car T

Autologous chimeric antigen receptor (CAR)-T cell therapy has shown great promise in various hematologic malignancies. However, the complexities associated with immune cell evasion are prevalent causes of disease relapse in many cancers. With the advent of pluripotent stem cell (iPSC)-derived CAR-T cells, many factors that hamper therapeutic efficacy of CAR-T cells can be addressed through multiplexed engineering at the clonal level. This includes enhanced potency, increased capacity for multi-antigen targeting, and the consistency of a clonally derived engineered cellular product for off-the-shelf patient administration. In particular, strategies to mitigate antigen escape and address tumor heterogeneity may help promote durable responses. To combine the potent targeted therapy of the CAR with universal targeting of secondary and tertiary antigens, we expressed an MR1 clonal T cell receptor (TCR) and a high-affinity, non-cleavable CD16 Fc receptor (hnCD16) in our iPSC-derived CAR19 T cells (CAR19-iT cells) directed to leukemia and lymphoma and CAR-MICA/B T cells directed to solid tumors. The MR1-TCR allows highly specific recognition of tumor associated antigen presented by the MR1 protein. The non-polymorphic MHC class I-related protein MR1 is widely expressed with minimal variability among patients and enables the unique prospect to be a universal cancer immunotherapy by using the cognate MR1-TCR. The hnCD16 Fc receptor has been shown to improve antibody-dependent cellular cytotoxicity (ADCC) leveraging the broad range of available therapeutic monoclonal antibodies to target clinically validated tumor antigens. A preliminary assessment demonstrated that MR1-TCR overexpressed in T cells allowed for enhanced recognition of multiple hematological and solid tumor cell lines. Notably, prominent target specific killing was seen in A549 lung carcinoma cells (>75% reduction in total viable cells) with the directed cytotoxicity specifically inhibited by an MR1 blocking antibody. Next, in vitro functional testing was performed on the engineered CAR19-iT cells in co-culture assays where we measured killing of tumor cells via MR1-TCR engagement and via hnCD16 mediated ADCC. Specifically, we show that CAR19-iT cells expressing hnCD16 can be efficiently directed to lyse CD20+ Raji cells in the presence of rituximab or HER2+ SKOV3 cells in the presence of Herceptin, demonstrating the potential to target both hematological malignancies and solid tumors with one target modality in combination with various monoclonal antibodies. Moreover, CAR19-iT cells expressing either MR1-TCR or hnCD16 show the ability to control growth of CD19 KO lymphoma cells in the co-culture assays, further highlighting the unique ability to elicit multiple ways to target antigen escape. Further in vitro and in vivo combinatorial targeting studies focused on antigen escape and tumor heterogeneity are ongoing and will be discussed. In summary, the advances presented here demonstrate that both the MR1-TCR and hnCD16 modalities synergize with CAR-iT cells as an off-the-shelf therapeutic that can provide durable responses and enable broad applicability for targeting of additional tumor antigens where single-agent therapeutics fail to provide clinical benefit for patients. Disclosures Nguyen: Fate Therapeutics, Inc.: Current Employment. Peralta:Fate Therapeutics, Inc.: Current Employment. Lu:Fate Therapeutics, Inc.: Current Employment. Sung:Fate Therapeutics, Inc.: Current Employment. Lee:Fate Therapeutics, Inc.: Current Employment.

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