scholarly journals Induction of murine peritoneal gamma/delta T cells and their role in resistance to bacterial infection.

1993 ◽  
Vol 178 (3) ◽  
pp. 971-984 ◽  
Author(s):  
M J Skeen ◽  
H K Ziegler
Keyword(s):  
T Cells ◽  
T Cell ◽  
Peritoneal Cavity ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Gram Positive ◽  
Gram Negative ◽  
A Site ◽  
Gamma Delta T Cell

Previous studies have reported an association of gamma/delta T cells with microbial infection in both human lesions and murine infectious disease models. In this study we provide a comprehensive analysis of the conditions under which the induction of gamma/delta T cells occurs at a site of infection. We found a site-specific induction of gamma/delta T cells after the injection of Listeria monocytogenes in the peritoneal cavity of C3H mice. No changes were seen in the splenic or lymph node populations after these injections. Both the proportion and the absolute number of gamma/delta T cells increased in the peritoneal cavity. Additionally, when peritoneal T cells from Listeria-immune mice were restimulated in vitro, the induced gamma/delta T cells exhibited a greater expansion potential than the alpha/beta T cells. Neither the induced gamma/delta T cells nor those from normal mice expressed CD4 or CD8 on the cell surface. Thy-1 was expressed on only 29% of normal peritoneal gamma/delta T cells, but after intraperitoneal Listeria injection 65% of induced gamma/delta T cells expressed. Thy-1, Pgp-1 and CD45R expression on both normal and induced gamma/delta T cells was consistent with an activation phenotype. Significant increases in peritoneal gamma/delta T cells were not seen until 5-7 d after Listeria injection. The proportion of the CD3+ population expressing the gamma/delta T cell receptor remained elevated for 6-7 wk, while the absolute numbers of peritoneal gamma/delta T cells declined gradually over this time period, reflecting a decrease in both the number of lymphocytes and the percentage of these that were CD3+. Peak numbers of gamma/delta T cells were seen at day 10 with live microbes such as Listeria. A variety of microbes, toxins, mitogens, antigens, cytokines, and nonspecific inflammatory agents were evaluated for their ability to induce gamma/delta T cells in the peritoneal cavity. Both Gram-positive and Gram-negative bacteria as well as Mycobacteria were able to induce gamma/delta T cells that showed increased in vitro expansion potential. An exotoxin from a Gram-positive organism, listeriolysin-o, and the lipopolysaccharide (LPS) endotoxin from a Gram-negative organism were also effective. gamma/delta T cell responses to LPS were under lps gene control. Peak numbers of gamma/delta T cells were observed at day 3 after injection with exotoxins and endotoxins. Modifications that abrogated the virulence of a bacterial strain also eliminated the inductive effect for gamma/delta T cells.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Intercellular interactions and cytokine responsiveness of peritoneal alpha/beta and gamma/delta T cells from Listeria-infected mice: synergistic effects of interleukin 1 and 7 on gamma/delta T cells.

1993 ◽  
Vol 178 (3) ◽  
pp. 985-996 ◽  
Author(s):  
M J Skeen ◽  
H K Ziegler
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Population ◽  
T Cell Subsets ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Accessory Cells ◽  
Alpha Beta ◽  
Gamma Delta T Cell

Peritoneal gamma/delta T cells from Listeria-immune mice show an enhanced potential to expand when restimulated with antigens or mitogens in vitro (see companion paper [Skeen, M. J., and H. K. Ziegler. 1993. J. Exp. Med. 178:971]). When cocultured with peritoneal alpha/beta T cells, the gamma/delta T cell population expanded preferentially even when the in vitro stimulus was specific for the alpha/beta T cell population. Purified gamma/delta T cells did not respond to alpha/beta T cell-specific stimuli. If isolated T cell subsets were recombined in cell mixing experiments, the resulting proliferative response was greater than additive. Irradiated alpha/beta T cells could enhance the proliferation of responding gamma/delta T cells, but the effect was unidirectional; i.e., irradiated gamma/delta T cells did not stimulate responding gamma/delta T cells. This effect appeared to be cytokine mediated and did not require cell-cell contact. Both recombinant interleukin 2 (rIL-2) and rIL-7 could support the expansion of the gamma/delta T cells, while rIL-7 was only minimally stimulatory for the alpha/beta T cells. The magnitude of the response by gamma/delta T cells to rIL-7 exceeded the response to other in vitro stimuli, including immobilized anti-T cell receptor monoclonal antibody, and was 50-100-fold greater than the alpha/beta T cell response to IL-7. This unique sensitivity of gamma/delta T cells to IL-7 was strongly enhanced by the presence of accessory cells. These cells could be replaced by rIL-1, establishing a synergy for IL-1 and IL-7 as factors that could uniquely stimulate this gamma/delta T cell population. Isolated peritoneal gamma/delta T cells from Listeria-immune mice react to heat-killed Listeria preparations in the presence of macrophages accessory cells in a non-H-2-restricted manner. Considered collectively, these results suggest a potential mechanism by which gamma/delta T cells can predominate in epithelial tissues and at sites of infection.

Rapamycin Together With TGF-β1, IL-2 and IL-15 Induces The Generation Of Functional Regulatory γδT Cells From Human Peripheral Blood Mononuclear Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3482-3482
Author(s):  
Yanjun Gu ◽  
Yongxian Hu ◽  
Kaimin Hu ◽  
Weichao Liao ◽  
Feilin Zheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Human Immune System ◽  
Gamma Delta T Cell ◽  
Tgf Β1

Abstract Gamma delta T cell, expressing gamma delta T cell receptor (gamma delta TCR), is considered as a group of unconventional T cells linking innate and adaptive immunity. Although gamma delta T cells only represent a minor population in human immune system, their functions are very broad. Recent researches have suggested that depending on the microenvironment, gamma delta T cells can assume features reminiscent of Th1, Th2, Th17 and regulatory T cells (Treg) as well as professional antigen present cells. Regulatory gamma delta T cell (gamma delta Treg) is a recently reported subset of gamma delta T cells characterized by both expressions of gamma delta TCR and forkhead/winged-helix family transcriptional repressor p3 (Foxp3), with potential immunosuppressive functions. Researches that focused on gamma delta Treg have showed the regulatory roles it has in preventing autoimmune response and relieving autoimmune diseases such as systemic lupus erythematosus (SLE), and the suppressive activity of breast tumor-derived gamma delta Tregs on innate and adaptive immunity, as well as the protective effects enhanced by gamma delta Tregs against xenogenic graft-versus-host disease in humanized mice found in our previous studies. All these observations suggest the important roles that gamma delta Treg plays in human immune system and its potential clinical applications. However, the further studies of gamma delta Treg are limited mainly due to its low quantities in vivo and the lack of methods to induce gamma delta Treg largely in vitro. It would be much significant if we found efficient induction and expansion methods for functional gamma delta Tregs. As the mammalian target of rapamycin (mTOR) is an important integrative kinase that acts as a crucial negative regulator of Treg differentiation and expansion, which can inhibit the expression of Foxp3 induced by TGF-β1, and Rapamycin (Rapa) is an immunosuppressive agent which acts through the blockade of mTOR, here we studied whether Rapa, together with TGF-β1/IL-2/IL-15, could induce and expand gamma delta Tregs derived from human peripheral blood mononuclear cells (hPBMCs) efficiently in vitro, under the stimulation of zoledronic acid (ZOL). Our results demonstrated that Rapa, synergized with TGF-β1/IL-2/IL-15, could not only facilitate the generation of gamma delta Tregs largely in vitro, with the percentage of induced gamma delta Tregs increasing from 2.4±1.2% cultured without TGF-β1/IL-15 nor Rapa, to 55.2±8.2% with Rapa and TGF-β1/IL-2/IL-15 together, compared with 26.2±6.7% with TGF-β1/IL-2/IL-15 but no Rapa (as Figure 1A indicated), but also enhanced the Foxp3 and CD25 expression levels in Rapa-induced gamma delta Tregs (as Figure 1C). Other regulatory-associated molecules expressed in Rapa-induced gamma delta Tregs included CTLA-4, ICOS and HLA-DR, and approximately no CD127, which were somehow similar with conventional CD4+CD25+ Tregs and were related with strong immunosuppressive functions. Through the co-culturing with naïve T cells derived from hPBMCs in vitro, we found that thus-induced gamma delta Tregs displayed concentration-dependent suppressive activity against the proliferation of naïve T cells, and this suppressive function appeared much greater in Rapa-induced gamma delta Tregs, compared with those induced without Rapa (as Figure 1B indicated).Figure 1Figure 1. In conclusion, our results demonstrated that Rapa, combined with TGF-β1/IL-2/IL-15, could induce and expand gamma delta Tregs largely in vitro and thus-induced gamma delta Tregs expressed high levels of Foxp3 and CD25, and displayed significant immunosuppressive activities in vitro, which provided bases to some extent for the further studies on gamma delta Treg and its potential clinical applications. Disclosures: No relevant conflicts of interest to declare.

600 In vitro anticancer and immunomodulatory activities of NBT-167, a dimer of resveratrol

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A635-A635
Author(s):  
Jeffrey Zhang ◽  
Everett Henry ◽  
L Harris Zhang ◽  
Wanying Zhang
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Immune Cells ◽  
Cell Killing ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Raw264.7 Macrophages

BackgroundResveratrol (3,4’,5-trihydroxystilbene), a stilbenoid isolated from many species of plants, is widely known for its antioxidative, anti-inflammatory, immunomodulatory and anticancer activities. Recently, novel resveratrol oligomers have been isolated from various plants; their diverse structures are characterized by the polymerization of two or more resveratrol units. Little is known regarding the anticancer and immunomodulating activities of these oligomers. In this study, we designed in vitro models to compare resveratrol side by side with its natural dimer NBT-167 for their anticancer and immunological activities.MethodsWe isolated resveratrol and its dimer (NBT-167) from plants. The potency of the compounds was compared side by side using cancer cell survival assays and immunological assays with various types of human cells including cancer cell lines, PBMCs and enriched NK, gamma delta T cells, THP-1 monocytic cells, HL-60 promyelocytic leukemia cells as well as mouse RAW264.7 macrophages.ResultsNBT-167 was found to be more potent than resveratrol in inhibiting growth of various cancer cells and modulation of cytokine production from anti-IgM, LPS, PHA or SEB stimulated PBMC. Both compounds similarly enhanced IL-2 stimulated NK and gamma delta T cell killing activity against K562 cells and modulated nitric oxide production from LPS/IFN-g induced RAW264.7 macrophages and phagocytotic activity of HL-60 cells. NBT-167 was slightly more potently than resveratrol in inhibiting chemotaxis of HL-60 cells and blocking cell cycle of THP-1 and HL-60 cells at G1/S transition. In addition, NBT-167, but not resveratrol, could increase IL-2 production and T cell proliferation stimulated with anti-CD3 and anti-CD28 and synergize with anti-PD-1 antibody to increase IL-2 and IFN-gamma production in co-culture of allotypic T cells and dendric cells (MLR).ConclusionsOur data showed that NBT-167, a dimer of resveratrol, had anticancer and immunomodulatory activities such as modulation of expression of cytokines in immune cells and induction of cancer cell-killing activities of NK and gamma delta T cells. Generally, NBT-167 appeared to have higher activities than resveratrol in modulating immune cells and inhibiting cancer cells. NBT-167 could be a promising cancer immunotherapeutic agent targeting both cancer cells and immune cells.

scholarly journals Human fetal liver gamma/delta T cells predominantly use unusual rearrangements of the T cell receptor delta and gamma loci expressed on both CD4+CD8- and CD4-CD8- gamma/delta T cells.

1993 ◽  
Vol 177 (2) ◽  
pp. 425-432 ◽  
Author(s):  
K W Wucherpfennig ◽  
Y J Liao ◽  
M Prendergast ◽  
J Prendergast ◽  
D A Hafler ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Fetal Liver ◽  
Cell Populations ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Gamma Chain ◽  
T Cell Clones ◽  
Cell Clones ◽  
Gamma Delta T Cell

Substantial numbers of both alpha/beta and gamma/delta T cells are present in human fetal liver, which suggests a role of the fetal liver in T cell development. The diversity of fetal liver T cell receptor (TCR) gamma and delta chain rearrangements was examined among both CD4+CD8- and CD4-CD8- gamma/delta T cell clones. In addition, TCR delta chain transcripts from three fetal livers were sequenced after polymerase chain reaction amplification of TCR delta chains with V delta 1 or V delta 2 rearrangements. Five of six fetal liver gamma/delta T cell clones had a V delta 2-D delta 3-J delta 3 gene rearrangement with limited junctional diversity; three of these clones had an unusual CD4+CD8- phenotype. V delta 2-D delta 3-J delta 3 gene rearrangements were also common among both in-frame and out-of-frame transcripts from three fetal livers, indicating that they are the result of an ordered rearrangement process. TCR gamma chain sequences of the fetal liver gamma/delta T cell clones revealed V gamma 1-J gamma 2.3, V gamma 2-J gamma 1.2, and V gamma 3-J gamma 1.1 rearrangements with minimal incorporation of template-independent N region nucleotides. TCR gamma chain rearrangements found in these fetal liver T cell clones were different from those that have been observed among early thymic gamma/delta T cell populations, while similar TCR delta chain rearrangements are found among gamma/delta T cells from both sites. These data demonstrate that the fetal liver harbors gamma/delta T cell populations distinct from those found in the fetal thymus, suggesting that the fetal liver is a site of gamma/delta T cell development in humans. These unusual T cell populations may serve a specific function in the fetal immune system.

Bovine gamma delta T cells and the function of gamma delta T cell specific WC1 co-receptors

2015 ◽  
Vol 296 (1) ◽  
pp. 76-86 ◽  
Author(s):  
Janice C. Telfer ◽  
Cynthia L. Baldwin
Keyword(s):  
T Cells ◽  
T Cell ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Gamma Delta T Cell

scholarly journals Zoledronic Acid Induces the Proliferation of Human Cord Blood Gamma Delta T Cells Ex Vivo

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1427-1427
Author(s):  
Suzanne L Tomchuck ◽  
Jin He ◽  
Ross W. Perko ◽  
Scarlett Evans ◽  
Amy McKenna ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Fold Increase ◽  
T Cell Proliferation ◽  
Gamma Delta T Cells ◽  
Memory Cells ◽  
Gamma Delta ◽  
Gamma Delta T Cell

Abstract Cord blood (CB) T cells are known to be naïve cells, but can be activated to respond similar to adult peripheral blood (PB) T cells. Reports indicate that culture with aminobisphosphonate (NBP) stimulates CB gamma delta T cell proliferation ex vivo, specifically the TCRγ9δ2 subset, which has been extensively studied in PB gamma delta T cells. As CB gamma delta T cells are not well described, we compared CB gamma delta T cell proliferation, phenotype and genotype to PB gamma delta T cells when culturing cells with the NBP, Zometa (zoledronic acid), and IL-2. Fourteen days in culture resulted in significant fold increase in the proliferation of gamma delta T cells and in the percent of lymphocytes in both sample types. PB gamma delta T cells proliferated more robustly than CB with a 288.60 versus 21.32 fold increase, respectively. Additionally, in freshly isolated samples, CB gamma delta T cells comprised an average of 1.404% of the lymphocyte population, which was similar to PB gamma delta T cells, with an average of 2.319%. However, by day 14, PB gamma delta T cells increased to 70.15% of lymphocytes whereas CB gamma delta T cells increased to 12.49%. Phenotypically, both CB and PB had similar percent of CD45RA+ and CD45RO+ gamma delta T cell memory subsets in freshly isolated samples. Following culture, PB gamma delta T cells were mostly CD45RO+ memory cells, with significantly fewer CD45RA+ naïve cells, whereas more CB gamma delta T cells were of the intermediate CD45RA+CD45RO+ subset. Further phenotypic analysis of the memory subsets indicated that cultured PB gamma delta T cells were either effector memory cells (CD27-CD45RA-) or central memory cells (CD27+CD45RA-), while CB gamma delta T cells were mostly naïve (CD27+CD45RA+). The cytokines secreted by these cells were also assessed and the culture of PB and CB gamma delta T cells resulted in differing cytokine secretion profiles. After 14 days of culture, PB gamma delta T cells secreted more IFNγ and TNFα, while CB gamma delta T cells secreted more IL-10 and RANTES. We also examined TCRγ9 and TCRδ2 phenotypic expression and found that the TCRγ9δ2 was a common clone in freshly isolated PB gamma delta T cells, which predominated after 14 days in culture. However, while the TCRγ9δ2 variant was expressed in CB gamma delta T cells, it was low before and after culture, suggesting that Zometa may not stimulate gamma delta T cells in CB the same as PB. As limited TCRγδ phenotypic reagents are available, we developed a single cell PCR assay for genotypic analysis of the TCRγδ repertoire. PCR analysis suggests that the TCRγδ repertoire is diverse in both samples, yet TCRγ9δ2 is most prevalent. Further analysis of the variant subsets is warranted and may give insight into how each of these receptor pairings affects function. Disclosures No relevant conflicts of interest to declare.

scholarly journals Ontogenic development and tissue distribution of V gamma 1-expressing gamma/delta T lymphocytes in normal mice.

1995 ◽  
Vol 182 (6) ◽  
pp. 1921-1930 ◽  
Author(s):  
P Pereira ◽  
D Gerber ◽  
S Y Huang ◽  
S Tonegawa
Keyword(s):  
T Cells ◽  
T Cell ◽  
Intestinal Epithelium ◽  
Lymphoid Organs ◽  
Cell Subpopulation ◽  
Postnatal Life ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Adult Mice ◽  
Gamma Delta T Cell

A hamster monoclonal antibody (mAb) recognizing an epitope in the V gamma 1-J gamma 4-C gamma 4 chain of the gamma/delta T cell receptor has been generated. Using this mAb, we have quantitated the occurrence of V gamma 1-bearing gamma/delta T cells in the developing thymus and in the lymphoid organs and several epithelia of adult mice. The V gamma 1-expressing cells constitute a minor gamma/delta T cell subpopulation during fetal and early postnatal life, but they constitute a major population of gamma/delta T cells in the thymus and in the peripheral lymphoid organs in adult mice. In addition, we found that V gamma 1-bearing cells comprise a large proportion (15-60%) of the gamma/delta T cells present in the intestinal epithelium (i-IEL) in all strains of mice tested. V gamma 1+ i-IEL are present in athymic (nude) mice and in antigen-free mice, demonstrating that they can develop extrathymically and that their presence in the intestinal epithelium is independent of the antigenic load of the gut. Our results show that V gamma 1-bearing lymphocytes account for the largest population of gamma/delta T cells in the mouse. This population includes a thymus-dependent component that homes to the secondary lymphoid organs and a thymus-independent component that constitutes a major fraction of the gamma/delta i-IELs.

scholarly journals Retroviral transformation in vitro of chicken T cells expressing either alpha/beta or gamma/delta T cell receptors by reticuloendotheliosis virus strain T.

1993 ◽  
Vol 177 (3) ◽  
pp. 647-656 ◽  
Author(s):  
M D Marmor ◽  
T Benatar ◽  
M J Ratcliffe
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Reticuloendotheliosis Virus ◽  
Spleen Cells ◽  
Gamma Delta ◽  
Alpha Beta ◽  
Gamma Delta T Cell

Exposure of normal juvenile chicken bone marrow cells to the replication defective avian reticuloendotheliosis virus strain T (REV-T) (chicken syncytial virus [CSV]) in vitro resulted in the generation of transformed cell lines containing T cells. The transformed T cells derived from bone marrow included cells expressing either alpha/beta or gamma/delta T cell receptors (TCRs) in proportions roughly equivalent to the proportions of TCR-alpha/beta and TCR-gamma/delta T cells found in the normal bone marrow in vivo. Essentially all TCR-alpha/beta-expressing transformed bone marrow-derived T cells expressed CD8, whereas few, if any, expressed CD4. In contrast, among TCR-gamma/delta T cells, both CD8+ and CD8- cells were derived, all of which were CD4-. Exposure of ex vivo spleen cells to REV-T(CSV) yielded transformed polyclonal cell lines containing > 99% B cells. However, REV-T(CSV) infection of mitogen-activated spleen cells in vitro resulted in transformed populations containing predominantly T cells. This may be explained at least in part by in vitro activation resulting in dramatically increased levels of T cell REV-T(CSV) receptor expression. In contrast to REV-T(CSV)-transformed lines derived from normal bone marrow, transformed lines derived from activated spleen cells contained substantial numbers of CD4+ cells, all of which expressed TCR-alpha/beta. While transformed T cells derived from bone marrow were stable for extended periods of in vitro culture and were cloned from single cells, transformed T cells from activated spleen were not stable and could not be cloned. We have therefore dissociated the initial transformation of T cells with REV-T(CSV) from the requirements for long-term growth. These results provide the first demonstration of efficient in vitro transformation of chicken T lineage cells by REV-T(CSV). Since productive infection with REV-T(CSV) is not sufficient to promote long-term growth of transformed cells, these results further suggest that immortalization depends not only upon expression of the v-rel oncogene but also on intracellular factor(s) whose expression varies according to the state of T cell physiology and/or activation.

scholarly journals 688 In vivo expansion of gamma delta T cells by a CD19-targeted butyrophilin heterodimer leads to elimination of peripheral B cells

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A727-A727
Author(s):  
Suresh De Silva ◽  
George Fromm ◽  
Louis Gonzalez ◽  
Arpita Patel ◽  
Kyung Yoon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Mechanism Of Action ◽  
Peripheral Blood ◽  
Fusion Proteins ◽  
Gamma Delta T Cells ◽  
Gamma Delta ◽  
Gamma Delta T Cell

BackgroundA primary mechanism of cancer immunotherapy resistance involves downregulation of specific antigens or major histocompatibility complex based antigen presentation, which renders tumor cells invisible to alpha-beta T cells, but not gamma-delta T cells. Recently, a two-step model of gamma-delta T cell activation has emerged, wherein one butyrophilin (BTN, ie. BTN2A1) directly binds the gamma-delta TCR but is only activated if certain molecular patterns (eg. phosphoantigens) facilitate recruitment of a second BTN (ie. BTN3A1) into a complex to form a BTN2A1/3A1 heterodimer. The BTN2A1/3A1 complex specifically activates the predominant gamma-delta T cell population in the peripheral blood, comprising the Vg9d2 T cell receptor (TCR), but does not activate the primary gamma-delta T cell population in mucosal tissues, comprising the Vg4 TCR. The unique mechanism of action and specificity of gamma-delta TCR/BTN interactions suggests that therapeutic proteins comprising specific BTN heterodimers could be used to target specific gamma-delta T cell populations, with a lower risk of off-target activation common with CD3-directed T cell engagers.MethodsHuman BTN2A1/3A1-Fc-CD19scFv and mouse BTNL1/6-Fc-CD19scFv heterodimeric fusion proteins were purified and binding to CD19 or the respective gamma-delta TCRs was assessed by ELISA, Octet and flow cytometry using gd T-cells isolated from human peripheral blood and mouse intestinal tissue. The functionality of the constructs to activate gamma-delta T cells and mediate killing of tumor cells was assessed using live cell imaging in vitro as well as a murine B-cell lymphoma model in vivo.ResultsThe CD19-targeting scFv domains of the BTN heterodimer fusion proteins bound to human and mouse CD19 with low nanomolar affinity. The BTN2A1/3A1-Fc-CD19scFv compound specifically bound to the Vg9d2 TCR on human gd T cells while the mouse BTNL1/6-Fc-CD19scFv bound to Vg7d4 TCR on mouse gd T cells. Both compounds were able to activate gd T cells in a co-culture assay resulting in degranulation and increased surface expression of CD107a and also increased apoptosis of CD19+ tumor cells. Intraperitoneal administration of the mouse BTNL1/6-Fc-CD19scFv led to anti-tumor effects in A20 tumor bearing BALB/c mice. Phenotyping from BTNL1/6-Fc-CD19scFv treated mice revealed profound and rapid expansion of the endogenous gamma-delta T cells in the circulation and tumor, with concomitant depletion of peripheral CD19+ B-cells, confirming the mechanism of action of the heterodimer as a gamma-delta T cell specific engager.ConclusionsThese results provide proof of mechanism for in vivo manipulation of gamma-delta T cells using antigen-targeted butyrophilin heterodimeric fusion proteins for the treatment of cancer.

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