scholarly journals A CD6-Targeted Antibody-Drug Conjugate As a Potential Therapy for T Cell-Mediated Disorders

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3817-3817
Author(s):  
Linjun Zhang ◽  
Liping Luo ◽  
Joel Chen ◽  
Rupesh Singh ◽  
William Baldwin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
Cancer Cells ◽  
Adoptive Transfer ◽  
Humanized Mice ◽  
Human Pbmc ◽  
Nsg Mice ◽  
Flow Cytometric ◽  
Antibody Drug

Abstract INTRODUCTION Pathogenic T cells cause many diseases including most autoimmune diseases and graft-versus-host disease (GVHD). Selectively targeting these pathogenic T cells while sparing the normal T cells and other tissues is a "holy grail" of therapeutics development in modern clinical immunology. So far, pan-immunosuppressive drugs such as corticosteroids are used to treat these patients, with limited efficacy and severe adverse effects. It is also well-established that these pathogenic T cells, whether auto- or alloreactive, proliferate following antigen recognition to cause tissue damage while the other normal T cells remain quiescent. Selectively targeting the proliferating T cells could be an effective strategy to develop new drugs for diseases mediated by the pathogenic T cells. Antibody-drug conjugates (ADCs) are developed by conjugating a potent toxin onto a monoclonal antibody (mAb) specific for a cancer cell surface antigen. Monomethyl auristatin E (MMAE), a synthetic mitotic toxin, is the payload in several FDA-approved ADCs, and it kills the actively dividing cancer cells by blocking the polymerization of tubulin, rapidly inducing apoptosis. These cancer cells and pathogenic T cells have one feature in common-both of them are actively proliferating, thus, this ADC approach proven successful in cancer treatment could be re-purposed to selectively kill pathogenic T cells for the treatment of T cell-mediated diseases. CD6 is a cell surface glycoprotein that is expressed at high levels on all T cells except Treg cells, a small portion of B cells and many human NK cells. CD6 is not detectable on other tissue cells, making it a highly specific target candidate for T cells. We have generated CD6 knockout mice and CD6 humanized mice, and developed anti-CD6 mAbs that treat mouse models T cell-mediated diseases. A CD6-targeted ADC (CD6-ADC) thus might be effective for treating T cell-mediated diseases by selectively eliminating the proliferating pathogenic T cells. METHODS A CD6-ADC was developed by conjugating a latent form of MMAE onto the high-affinity anti-human CD6 mAb. Its potency of selectively killing pathogenic T cells was evaluated in an antigen-specific T cell recall assay with BrdU-incorporation followed by flow cytometric analyses. To determine the toxicity of the CD6-ADC on normal quiescent T cells, naïve CD6 humanized mice were treated with the CD6-ADC or non-binding control ADC (0.5 mg/kg) by intraperitoneal injection, then numbers of circulating T cells were monitored by flow cytometry daily. To evaluate the efficacy of CD6-ADC in treating T cell-mediated autoimmune diseases, the same dose (0.5 mg/kg) of CD6-ADC, or the parental anti-CD6 mAb, or the control ADC was used to treat a model of autoimmune uveitis, and disease severities were assessed by various ocular imaging techniques including indirect ophthalmoscopy, confocal scanning laser ophthalmoscopy and optical coherence tomography. To examine the potential of the CD6-ADC in treating GVHD, the same dose (0.5mg/kg) of CD6-ADC or control ADC was tested in a model of GVHD induced in NSG mice after adoptive transfer of human PBMC. GVHD severities were assessed by flow cytometric analyses of circulating human T cells and by histopathological analyses of different tissues. RESULTS: The CD6-ADC selectively killed antigen-specific proliferating T cells in vitro. Treating naive CD6-humanized mice with this CD6-ADC (0.5 mg/kg) did not significantly eliminate normal T cells in vivo. Furthermore, systemic delivery of the same dose (0.5 mg/kg) of CD6-ADC, but not the anti-CD6 mAb alone nor the control IgG effectively reduced retinal inflammation in a preclinical model of autoimmune uveitis. The same dose of CD6-ADC, but not the control ADC, also effectively depleted activated xenogeneic T cells and prevented the development of GVHD in NSG mice after the adoptive transfer of human PBMC. CONCLUSION: These data indicate that this CD6-ADC holds promise as a new drug for treating diseases in which T cells are integrally involved in the pathogeneses such as GVHD. Figure 1 Figure 1. Disclosures Lin: Takeda Pharma: Consultancy, Research Funding.

CLL Cells Can Diversify, Switch, and Differentiate in Response to Autologous T Cell Stimuli Present in a Murine Adoptive Transfer Model

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 315-315
Author(s):  
Piers E.M. Patten ◽  
Shih-Shih Chen ◽  
Davide Bagnara ◽  
Rita Simone ◽  
Sonia Marsilio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Adoptive Transfer ◽  
De Novo ◽  
Conflicts Of Interest ◽  
Transfer Model ◽  
B Cell Differentiation ◽  
Cell Numbers ◽  
Nsg Mice

Abstract Abstract 315 Adoptive transfer of primary patient CLL cells into NOD/SCID/γcnull(NSG) mice results in engraftment and proliferation of CLL cells if autologous T cells are present. Formation of splenic follicles consisting of B cells interspersed and surrounded by T cells indicates engraftment. However, ultimately these CD20+ cells are lost several weeks later. We describe one of the mechanisms for this apparent loss: differentiation to plasma cells. Peripheral blood cells from 9 IgM+ CLL patients (6 U-CLL and 3 M-CLL) were adoptively transferred into NSG mice with enriched autologous CD3+ cells pre-activated with anti-CD3/28 beads. B and T cell engraftment and subset distributions were analyzed for 47 mice by immunohistochemistry (IHC) and flow cytometry (FC) at the time of sacrifice. The earliest and latest times of assessment were 12 and 124 days, respectively, after CLL cell injection. In some cases, CLL cells were labeled with CFSE to track cell division. At sacrifice, 3 engraftment patterns were observed. Pattern 1 (observed up to day 56) showed small follicles of CD20+ cells with low-moderate numbers of surrounding T cells. Intensely positive CD38 cells were inconspicuous. FC showed CD19+CD5+ cells with no increase in CD38 and variable CFSE dilution indicating lower levels of proliferation. Pattern 2 (observed throughout the study period) showed much higher T and B cell numbers. CD20+ cells were interspersed with and surrounded by principally CD4+ cells which were activated and functional as indicated by expression of Ki-67, PD-1, CD57, and T cell derived cytokines IFNγ and IL5 in plasma. Follicles contained CD20 and cytoplasmic Ig+ (cIg+) cells that double stained for IRF-4 and Blimp-1, transcription factors required for B cell differentiation. While Bcl-6 staining in these cells was minimal or absent, follicles from all 9 patients contained activation-induced deaminase (AID)+ cells. Cells with dim IgM expression localized to follicles; however, cells with intense IgM, IgA, or IgG were present both within, surrounding, and outside follicles matched by similar CD38 staining. Smaller populations of CD138+ cells surrounded follicles and were interspersed throughout non-follicular splenic areas. FC showed a novel CD19+CD5-CFSE-CD38++ population containing a CD138+ subset. Pattern 3 (observed in a limited subset of cases not before day 63) had minimal CD20+ cells by IHC, but noticeable populations of cIg+CD38+ and CD138+ cells interspersed amongst plentiful T cells. Such cells corresponded with cells with plasma cell morphology. Confirmation that differentiated cells were from the patient clone was achieved in 3 ways. First, in FACS sorted CD19+CD5+ and CD19+CD5-38++ cells from a subset of pattern 2 cases, RT-PCR revealed that all fractions contained both IGHC unswitched and switched clones identical to those found in the patients. Second, cases with pattern 3 engraftment generated CLL clonal switched and unswitched cDNA sequences. Finally, adoptive transfer of highly purified CD5+CD19+ patient cells generated IRF-4+Blimp-1+CD138+ cells. The generation of switched cells from all 9 patients indicated functional AID. In one U- CLL case, ultra-deep sequencing on pre-transfer and post-transfer human cells taken from mouse spleen revealed a significant number of new IGHVDJ mutations in spleen-derived cells. Such mutations targeted nucleotides typical for AID's action. In conclusion, CLL cells can diversify, switch, and differentiate in NSG mice in response to autologous T cell signals. The extent of this maturation is a function of T cell numbers and activity and the duration of the experiment. Differentiation without significant Bcl-6 expression suggests that follicles in NSG mice are not recapitulating classic germinal center reactions, possibly giving clues to the origin of CLL. Several features of poor prognosis disease were demonstrated (e.g., increased CD38 and AID expression with the development of clonally related switched transcripts) that might mirror clinical disease features. AID expressed by CLL cells is fully functional as indicated by de novo somatic hypermutation and class switch recombination. Both U-CLL and M-CLL clones respond in a similar manner in this model, suggesting the importance of T– B cell interactions in all types of CLL. Finally, the demonstration that cells can differentiate when appropriately induced may lead to novel therapeutic options for CLL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Fas counterattack: Fas-mediated T cell killing by colon cancer cells expressing Fas ligand.

1996 ◽  
Vol 184 (3) ◽  
pp. 1075-1082 ◽  
Author(s):  
J O'Connell ◽  
G C O'Sullivan ◽  
J K Collins ◽  
F Shanahan
Keyword(s):  
Colon Cancer ◽  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
Cancer Cells ◽  
Antisense Oligonucleotide ◽  
Fas Ligand ◽  
Immune Privilege ◽  
Colon Cancer Cells ◽  
Rt Pcr

Tumors escape immunological rejection by a diversity of mechanisms. In this report, we demonstrate that the colon cancer cell SW620 expresses functional Fas ligand (FasL), the triggering agent of Fas receptor (FasR)-mediated apoptosis within the immune system. FasL mRNA and cell surface FasL were detected in SW620 cells using reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical staining, respectively. We show that SW620 kills Jurkat T cells in a Fas-mediated manner. FasR-specific antisense oligonucleotide treatment, which transiently inhibited FasR expression, completely protected Jurkat cells from killing by SW620. FasL-specific antisense oligonucleotide treatment of SW620 inhibited its Jurkat-killing activity. FasL has recently been established as a mediator of immune privilege in mouse retina and testis. Our finding that colon cancer cells express functional FasL suggests it may play an analogous role in bestowing immune privilege on human tumors. HT29 and SW620 colon cancer cells were found to express FasR mRNA and cell surface FasR using RT-PCR and immunofluorescence flow cytometry, respectively. However, neither of these cells underwent apoptosis after treatment by the anti-FasR agonistic monoclonal antibody CH11. Our results therefore suggest a Fas counterattack model for immune escape in colon cancer, whereby the cancer cells resist Fas-mediated T cell cytotoxicity but express functional FasL, an apoptotic death signal to which activated T cells are inherently sensitive.

Enhanced Antitumor Efficacy of Adoptively Transferred CD19-Redirected CMV Specific Central Memory T Cells by CMV Vaccine.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3014-3014
Author(s):  
Xiuli Wang ◽  
Winnie Wong ◽  
Wen-Chung Chang ◽  
Don Diamond ◽  
Michael C. Jensen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antitumor Activity ◽  
Adoptive Transfer ◽  
Viral Antigen ◽  
Memory T Cells ◽  
Central Memory T Cells ◽  
Tumor Bearing ◽  
Nsg Mice

Abstract Abstract 3014 Development of T cell products that have engineered specificity for CD19 has broad application to adoptive transfer therapy for B-lineage lymphoma and leukemia. Clinical studies have demonstrated the safety and feasibility of cloned and bulk T cell transfer as a therapy for patients. But potency of this strategy has proven challenging, primarily due to issues relating to a lack of persistence of the adoptively transferred cells in patients. In contrast, the adoptive transfer of viral specific T cells has shown efficient efficacy for preventing progressive viral infections and exhibited long term persistence in patients, in part due to the viral specific T cells received optimal co-stimulation after engagement of their native receptors. Conceptually, engineering CMV specific T cells with CD19CAR to provide them with a second specificity for a tumor antigen may enable the transferred T cells (bi-specific T cells) to persist or numerically expand in vivo by stimulation of the endogenous TCR by virus antigen. Moreover, bi-specific T cell can be used in treatment for B cell malignancies in allo-settings without causing GVHD due to the pre-defined non-alloreactive TCR specificity. In this study, we explored the use of CMVxCD19CAR bi-specific T cells in CD19+tumor bearing NSG mice and evaluated their antitumor activity in response to CMVpp65 antigen stimulation as a consequence of CAR transduced T cell expansion. CMV specific T cells derived from central memory T cells were selectively expanded by 2 rounds of stimulation with cGMP grade pp65 protein followed a rapid expansion containing OKT3 and feeder cells. The established CMV specific Tcm, in which majority of them are CMVpp65 tetramer positive, were then transduced with cGMP grade SIN lentivirus expressing CD19R:CD28:z/EGFRt. After stimulation with CD19 positive LCL, 40% of the resultant cells co-express pp65 tetramer and CAR as detected by EGFRt/Erbitux analysis. Functionally, the bi-specific T cells exhibit specific cytolytic activity and secret IFNg, IL2 and TNFα upon engagement with pp65 or CD19 antigen, indicating that the effector function of the bi-specific T cells can be induced through endogenous TCR or the introduced CAR. To evaluate the in vivo viral antigen driven anti-tumor efficacy of the adoptively transferred bi-specific T cells, CD19+LCL expressing GFPffluc were inoculated (i.v) into huIL-15 reconstituted NSG mice. Once the tumor engraftment was confirmed by in vivo imaging, bi-specific T cells were adoptively transferred (i.v) into the tumor bearing mice. Anti- tumor activity was observed 14 days post T cell infusion. As expected, this effect is transient and tumor re-progression occurred. In order to deliver CMV antigen for vaccine, we generated T-APC by loading CMVpp65 peptide into autologous T cells and injected the CMV T-APCs (I.v) into the bi-specific T cell treated mice, Influenza specific MP1 peptide pulsed autologous T cells were used as control T-APCs. CMV T-APC induced a second wave of antitumor activity 2 weeks post vaccine and mice survived for more than 2 months post adoptive transfer of T cells, while tumor grew vigorously when MP1-T-APCs were given as stimulators. The findings demonstrated that CD19CAR modified CMV specific T cells are capable of responding to viral antigen reactivation through their endogenous TCR, which could be used to magnify the antitumor activity of CAR transduced T cells in vivo. Disclosures: No relevant conflicts of interest to declare.

Junctional Adhesion Molecule 2 Represents a Novel Subset of Hematopoietic Stem Cells Poised for T Lymphopoiesis

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3862-3862 ◽  
Author(s):  
Visnja Radulovic ◽  
Mark van der Garde ◽  
Valgardur Sigurdsson ◽  
Alya Zriwil ◽  
Svetlana Soboleva ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
Molecular Mechanisms ◽  
Cell Potential ◽  
Hematopoietic Stem ◽  
Nsg Mice ◽  
Cell Cycle Status

Abstract Phenotypically well-characterized hematopoietic stem cells (HSCs) still represent a heterogeneous pool of primitive cells regarding to their functionality. In particular, different lineage potential of HSCs have been considered as one of key features of the HSC heterogeneity. The lineage output of HSCs is often coupled with cell cycle status or long-term reconstitution potential, however molecular mechanisms of the mutuality are unclear and other type of the regulation may exist. In addition, prospective isolation of such HSCs biased towards specific lineage(s) is still problematic, as many of categorizations highly rely on retrospective information, e.g. transplantation assay. Although several markers have been reported to be able to subdivide HSCs into subcategories, exploration of additional markers will allow us understanding further molecular mechanisms of HSC regulations including activation and lineage choice. Here, we show that cell surface expression of Junctional adhesion molecule 2 (Jam2) represents higher reconstitution capacity of HSCs and the T cell potential. Flow cytometry analyses revealed that a subset of CD150+CD48-KSL cells in mouse bone marrow (BM) were positive for Jam2 (Jam2+HSC, 36.6 ±13.0 %), while other Jam family member Jam1 (F11r) was expressed on all HSCs and Jam3 was not detected. To examine functional differences of Jam2+ and Jam2-HSCs, 30 cells were separately transplanted into lethally irradiated mice. Peripheral blood analyses revealed that Jam2+HSCs reconstituted more efficiently than Jam2-HSCs (77.5 ±15.9 and 51.7 ±29.3 %, respectively). In case of transplantation using 5 cells, the frequency of reconstituted mice was higher in Jam2+HSCs (7 in 11) compared to Jam2-HSCs (4 in 11), indicating that Jam2+ population is more enriched for functional HSCs. The expression of Jam2 on HSC is reversible, but not hierarchical, as both Jam2+ and Jam2-HSCs reconstituted opposite population in the BM.Lineage analyses revealed that Jam2+HSCs have a greater potential in lymphoid cell reconstitution, particularly T cells, whereas the chimerism in myeloid cells was not significantly different from Jam2-HSCs. This tendency of higher contribution to the T cell development was even more pronounced in the secondary transplantation experiments, where the contribution of Jam2+HSCs in T cells was close to 100 %. Of note, most of Jam2+HSCs were in a dormant state, suggesting that the T cell (or lymphoid) potential of Jam2+HSCs is independent of cell cycle progression. Jam2 has been reported to interact with Jam1, which mediates the Notch signaling (Kobayashi et al., Nature, 2014). Competitive co-culture of Jam2+ vs Jam2-HSCs on OP9-DL1 showed that Jam2+HSCs dominated the T cell production, whereas no difference was seen in B cell production upon OP9 co-culture. Since Jam2 positivity correlates to T cell potential, we asked if altered T lymphopoiesis environment affects the cell surface Jam2 expression. Comparison of C57BL/6, NOD, NOD-Scid and NOD-Scid Il2rγ KO (NSG) mice showed that HSCs of NSG mice have significantly higher frequency of Jam2+HSCs, suggesting that cell surface Jam2 expression might be regulated by specific cytokine(s) binding to IL2Rγ. Our findings suggest Jam2 is a new marker for a subset of HSCs that preferentially generate T cells. In addition, this work uncouples the lineage choice and cell cycle status, which proposes a novel model to the lineage-determining machineries. Since efficient and immediate generation of T cells in transplantation therapy is important to minimize infectious risks, understanding the molecular basis of the Jam-Notch cooperation would contribute to establish safer and more efficient treatment. Disclosures No relevant conflicts of interest to declare.

scholarly journals Screening for Immunosuppressive Genes Responsible for Resistance Towards CAR-T Cell Therapy in Cancer Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4965-4965
Author(s):  
Aygul Valiullina ◽  
Alexey Petukhov ◽  
Regina Sayarova ◽  
Margarita Zhuravleva ◽  
Sevindzh Kletukhina ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Cancer Cells ◽  
Tumor Resistance ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T Cell Therapy ◽  
Car T ◽  
Antibody Drug

Abstract Despite expanding areas of clinical application for CAR-T cell therapy there is still lack of complete information about genes responsible for tumor resistance to this type of therapy. Widely known anti-PD-1 antibody drug Nivolumab and anti-CTLA-4 antibody drug Ipilimumab represent immunotherapeutics that activate the immune system against advanced melanoma and have proven superior to cytotoxic chemotherapy. However, in addition to existing ligands (i.e. CD80, CD86, PD-L1, PD-L2) there are supposedly other surface-expressed ligands stipulating the ability of cancer cells to suppress CAR-T efficacy. It may turn out that tumor resistance to CAR-T therapy is caused by previously unknown immunosuppressive genes. Revealing such genes could improve clinical outcomes by engineering enhanced CAR-T cells and antibodies capable of overcoming the gene-mediated resistance. In this study we propose the use of CRISPR technique and NGS sequencing to validate this hypothesis and identify novel genes that could presumably determine resistance towards CAR-T cells. The strategy is based on genome-wide screening using human CRISPR/Cas9 Synergistic Activation Mediator (SAM) pooled library that utilize an engineered protein complex for the transcriptional activation of endogenous genes. CAR-T cells were generated from healthy donor T cells genetically modified by lentiviral vectors and expanded ex vivo. Main steps of the experiment include:Amplification of pooled SAM library and use of NGS to confirm library representation.Generation of pooled lentiviral vectors using SAM library and transduction of HeLa cells.Generation of CAR-T cells.Co-cultivation of CAR-T and modified HeLa cells, selection of resistant cells.PCR analysis of sgRNA-containing fragment, followed by cloning of amplicons and NGS of amplicon library.Validation of identified genes to confirm resistance towards CAR-T cells. We generated a polyclonal CD19-positive HeLa cell line expressing dCas9-VP64 fusion and activation helper protein. This cell line was transduced with Human CRISPR Activation Library (SAM-3 plasmid system) and incubated with anti-CD19 CAR-T cells in order to select resistant cells and identify resistance-determining genes by NGS. Work supported by RFBR grant 18-315-00049 to A.P. and performed in accordance with Program of Competitive Growth of Kazan Federal University. References: A. Titov, A. Petukhov, A. Staliarova, D. Motorin, E. Bulatov, O. Shuvalov, S. Soond, M. Piacentini, G. Melino, Y. Zaritskey, N. Barlev. The biological basis and clinical symptoms of CAR-T therapy-associated toxicities. Cell Death & Disease (2018) Disclosures No relevant conflicts of interest to declare.

Adoptively Transferred Central Memory Derived Human CD8+Effectors Exhibit Superior Engraftment Fitness Over Their Naïve T Cell Derived Counterparts

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2982-2982
Author(s):  
Xiuli Wang ◽  
ChingLam W Wong ◽  
Brenda Aguilar ◽  
Wen-Chung Chang ◽  
Julie R Ostberg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Central Memory ◽  
Effector Memory ◽  
Effector Cells ◽  
Nsg Mice ◽  
Healthy Donors ◽  
Phosphorylated Akt

Abstract Abstract 2982 In clinical trials of adoptive T cell therapy, the persistence of transferred cells correlates with therapeutic efficacy. The engraftment fitness of ex vivo propagated T cells is in part pre-determined by the differentiation status of precursor T cells from which effector cell products are derived. In peripheral blood, T cells are comprised of three major subsets- naïve, central memory (Tcm) and effector memory (Tem), each having distinct phenotypic and functional attributes. We have previously shown that human CD8+ effector cells derived from Tcm were superior to Tem in their ability to engraft and persist following adoptive transfer (Wang, X. 2011). In this study, we set out to compare the engraftment fitness of CD8+ effector cells derived from naïve precursors with that of Tcm-derived effectors. FACS sorted CD8+ CD45RA+CD62L+ naïve (Tn) and CD8+CD45RO+CD62L+ Tcm cells from healthy donors were expanded in vitro for 14 days in the presence of OKT3, feeder PBMC and IL-2 at 50U/mL. Despite the comparable levels of CD28 expression on unstimulated CD8+ Tn and CD8+Tcm (91±2% for CD8+Naive and 94±2% for CD8+Tcm), Tcm-derived effector T cells (CD8+TCM/E) displayed significantly higher levels of CD28 expression with corresponding high levels of cytoplasmic phosphorylated-AKT as compared to Tn-derived cells (CD8+TN/E) (47±5% for CD8+TN/E vs. 83±4% for CD8+ TCM/E). After the initial 14 days of in vitro expansion, CD8+TCM/E were able to persist in vitro for more than 50 days in the presence of gamma-c cytokines (IL-2 50/ml or IL-15 10ng/ml) while CD8+TN/E failed to survive in either condition, which is consistent with the observed higher expression levels of IL-15R α and IL-2R β by CD8+TCM/E. After engraftment in huIL-15 replete immunodeficient (NSG) mice, we observed that CD8+TCM/E exhibited higher levels engraftment and mounted more robust proliferative responses to in vivo challenge with immunostimulatory vaccines. In contrast to CD8+TN/E, engrafted CD8+TCM/E reaquired/sustained high frequency of cells expressing IL-7Ralpha. To re-direct T cell specificity against B-lymphoid malignancies, purified CD8+Tn and CD8+Tcm from healthy donors were engineered with lentiviral vector encoding CD19R-CD28-EGFRt-epHIV7. CD19-specific CD8+TCM/E persist after adoptive transfer into the human IL15 reconstituted NSG mice, whereas no engraftment was detected in the CD19-specific CD8+TN/E infused NSG mice. These studies using human T cells support the use of central memory derived effector cells for adoptive therapy of cancer and infectious disease. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Longitudinal Changes in Cd4+, Cd8+ T Cell Phenotype and Activation Marker Expression Following Antiretroviral Therapy Initiation among Patients with Cryptococcal Meningitis

2019 ◽  
Vol 5 (3) ◽  
pp. 63
Author(s):  
Alice Bayiyana ◽  
Samuel Okurut ◽  
Rose Nabatanzi ◽  
Godfrey Zziwa ◽  
David R. Boulware ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Cell Surface ◽  
Cd8 T Cells ◽  
Cryptococcal Meningitis ◽  
Cd8 T Cell ◽  
Cd4 T Cell ◽  
Effector Memory ◽  
Memory Subset

Despite improvement in the prognosis of HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) patients on antiretroviral therapy (ART), cryptococcal meningitis (CM) still causes 10–15% mortality among HIV-infected patients. The immunological impact of ART on the CD4+ and CD8+ T cell repertoire during cryptococcal co-infection is unclear. We determined longitudinal phenotypic changes in T cell subsets among patients with CM after they initiated ART. We hypothesized that ART alters the clonotypic phenotype and structural composition of CD4+ and CD8+ T cells during CM co-infection. For this substudy, peripheral blood mononuclear cells (PBMC) were isolated at four time points from CM patients following ART initiation during the parent study (ClinicalTrials.gov number, NCT01075152). Phenotypic characterization of CD4+ and CD8+ T cells was done using T cell surface marker monoclonal antibodies by flow cytometry. There was variation in the expression of immunophenotypic markers defining central memory (CD27+CD45R0+), effector memory (CD45R0+CD27–), immune activation (CD38+ and Human Leucocyte Antigen DR (HLA-DR+), and exhaustion (Programmed cell death protein one (PD-1) in the CD4+ T cell subset. In comparison to the CD4+ T cell population, the CD8+ central memory subset declined gradually with minimal increase in the effector memory subset. Both CD4+ and CD8+ T cell immune exhaustion and activation markers remained elevated over 12 weeks. The relative surge and decline in the expression of T cell surface markers outlines a variation in the differentiation of CD4+ T cells during ART treatment during CM co-infection.

scholarly journals Cross-presentation of a TAP-independent signal peptide induces CD8 T immunity to escaped cancers but necessitates anchor replacement

2021 ◽  
Author(s):  
Koen A. Marijt ◽  
Lisa Griffioen ◽  
Laura Blijleven ◽  
Sjoerd. H. van der Burg ◽  
Thorbald van Hall
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cancer Cells ◽  
Cd8 T Cells ◽  
Antigen Processing ◽  
Signal Sequence ◽  
Cell Repertoire ◽  
Cross Presentation ◽  
Normal Tissues ◽  
Cell Immunity

AbstractCancer cells frequently display defects in their antigen-processing pathway and thereby evade CD8 T cell immunity. We described a novel category of cancer antigens, named TEIPP, that emerge on cancers with functional loss of the peptide pump TAP. TEIPPs are non-mutated neoantigens despite their ‘self’ origin by virtue of their absence on normal tissues. Here, we describe the development of a synthetic long peptide (SLP) vaccine for the most immunogenic TEIPP antigen identified thus far, derived from the TAP-independent LRPAP1 signal sequence. LRPAP121–30-specific CD8 T cells were present in blood of all tested healthy donors as well as patients with non-small cell lung adenocarcinoma. SLPs with natural flanking, however, failed to be cross-presented by monocyte-derived dendritic cells. Since the C-terminus of LRPAP121–30 is an unconventional and weakly binding serine (S), we investigated if replacement of this anchor would result in efficient cross-presentation. Exchange into a valine (V) resulted in higher HLA-A2 binding affinity and enhanced T cell stimulation. Importantly, CD8 T cells isolated using the V-variant were able to bind tetramers with the natural S-variant and respond to TAP-deficient cancer cells. A functional screen with an array of N-terminal and C-terminal extended SLPs pointed at the 24-mer V-SLP, elongated at the N-terminus, as most optimal vaccine candidate. This SLP was efficiently cross-presented and consistently induced a strong polyclonal LRPAP121–30-specific CD8 T cells from the endogenous T cell repertoire. Thus, we designed a TEIPP SLP vaccine from the LRPAP1 signal sequence ready for validation in clinical trials.

12 Development of an in vitro assay to assess bispecific T cell engager using T cells from CD3e humanized mice

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A12-A12
Author(s):  
Jun Zhou ◽  
Shuang Zhu ◽  
Hongjuan Zhang ◽  
Lei Zheng ◽  
Mingfa Zang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Lymphoblastic Leukemia ◽  
Humanized Mice ◽  
Activation Markers ◽  
In Vivo Models ◽  
Vitro Assay ◽  
Bite Antibody

BackgroundBispecific T cell engagers (BiTE) is a fast-growing class of immunotherapies. They are bispecific antibody that bind to T cell-surface protein (for example, CD3e) and a specific tumor associate antigen (TAA) on tumor cells, by which to redirect T cells against tumor cells in a MHC-independent manner. A successful example in the clinical is Blinatumomab, a BiTE antibody against CD3/CD19 approved in 2014 to treat acute lymphoblastic leukemia. Currently, many CD3-based BiTE are in clinical trials, including BCMAxCD3, Her2xCD3, CEAxCD3, and PSMAxCD3. To evaluate the efficacy of BiTE in vitro, human peripheral blood monocyte cells (hPBMC) are commonly being used as a source of T cells to co-culture with tumor cells. The disadvantage of using hPBMC is donor-to-donor variability and the availability of the original donor if a study needs to be repeated.MethodsTo overcome this, we proposed to replace hPBMC with T cells from human CD3e (hCD3) genetically engineered mouse models mice (GEMM) for in in vitro coculture assay. T cells were isolated from hCD3 GEMM mice using negative selection mouse T cell isolation kit. Conventional tumor cell lines or luciferase-engineered patient-derived-xenograft (PDX)-derived organoids (PDXO) expressing specific antigens are co-cultured with hCD3 T cells in 96-well plates in the presence of BiTE antibody.ResultsWe measured the killing of tumor cells using either flow cytometry or luciferase activity as readouts. To analyze tumor-reactivity of T cells to cancer cell line or organoids, IFN-gamma in the culture medium was measured and activation markers on T cells was assessed.ConclusionsOur data showed the feasibility of using humanized mice T cells as a replacement for hPBMCs to assess BiTE antibody in vitro. We are further validating the application of murine hCD3 T cells for in vivo models to test bispecific T cell engagers.

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