scholarly journals Is It Feasible to Use CMV-Specific T-Cell Adoptive Transfer as Treatment Against Infection in SOT Recipients?

2021 ◽  
Vol 12 ◽  
Author(s):  
Estéfani García-Ríos ◽  
Marcos Nuévalos ◽  
Francisco J. Mancebo ◽  
Pilar Pérez-Romero
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
T Cell Response ◽  
Cell Transplant ◽  
Cmv Infection ◽  
Hematopoietic Stem ◽  
Cell Immunity ◽  
Cell Adoptive Transfer ◽  
The Impact

During the last decade, many studies have demonstrated the role of CMV specific T-cell immune response on controlling CMV replication and dissemination. In fact, it is well established that transplanted patients lacking CMV-specific T-cell immunity have an increased occurrence of CMV replication episodes and CMV-related complications. In this context, the use of adoptive transfer of CMV-specific T-cells has been widely investigated and applied to Hematopoietic Stem Cell Transplant patients and may be useful as a therapeutic alternative, to reconstitute the CMV specific T-cell response and to control CMV viremia in patients receiving a transplantation. However, only few authors have explored the use of T-cell adoptive transfer in SOT recipients. We propose a novel review in which we provide an overview of the impact of using CMV-specific T-cell adoptive transfer on the control of CMV infection in SOT recipients, the different approaches to stimulate, isolate and expand CMV-specific T-cells developed over the years and a discussion of the possible use of CMV adoptive cellular therapy in this SOT population. Given the timeliness and importance of this topic, we believe that such an analysis will provide important insights into CMV infection and its treatment/prevention.

Rapid T Cell Recovery and Possible Auto-GVHD Following Adoptive Transfer of Ex-Vivo Costimulated Autologous T Cells at Day +2 Post-Transplant.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 769-769 ◽  
Author(s):  
Aaron P. Rapoport ◽  
Stephan A. Grupp ◽  
Edward A. Stadtmauer ◽  
Robert H. Vonderheide ◽  
Bruce L. Levine ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Ex Vivo ◽  
Cell Recovery ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
Cell Counts ◽  
Engraftment Syndrome ◽  
The Impact

Abstract Retrospective studies suggest that rapid lymphocyte recovery following autologous stem cell transplants (SCT) may be associated with better outcomes. Previously we showed that adoptive transfer of in-vivo vaccine-primed and ex-vivo (anti-CD3/anti-CD28) costimulated autologous T cells (ex-T) at about day 14 post-transplant increased CD4 and CD8 T cell counts at day 42 post-transplant and induced pneumococcal conjugate vaccine-directed T and B-cell responses [Rapoport et al, Nature Medicine, 2005]. In 2 current studies, we are further investigating the impact of ex-vivo costimulated autologous T cells on vaccine responses after SCT. In the first study, we are investigating whether a similar strategy of pre- and post-transplant immunizations along with an early infusion of vaccine-primed ex-T can induce responses to a putative tumor vaccine composed of 4 HLA-A2-restricted peptides derived from survivin and hTERT in pts undergoing SCT for myeloma. In the second (randomized) trial, the impact of early ex-T on immune recovery and vaccine reponses is being tested in pediatric neuroblastoma pts. Compared to the previous study, two methodologic changes were made: The target number of T cells infused was raised 5-fold to 5 x 1010 (109/kg) T cells were infused on day + 2 to take greater advantage of homeostatic expansion mechanisms. Patients were monitored for delayed hematopoietic recovery because of this switch to early ex-T and the fact that survivin and hTERT are also expressed in hematopoietic stem cells. At the time of submission, 16 adult and 30 pediatric patients have been enrolled on these trials of whom 11 and 21, respectively, are evaluable for post-transplant hematopoietic and T-cell recovery. On the myeloma trial, the mean # of T cells infused was 3.95 x 1010 with 96% viability and a CD4/CD8 ratio of 1.8:1. At day 14 post-transplant, the median CD4 count was 1951/mcl (range 651–7668) and the median CD8 count was 4117/mcl (range 1499–39,354). The median # days to achieve an absolute neutrophil count (ANC) > 500 was 12 (range 11–14) and the median # days to achieve a PLT count >20,000/mcl was 13 days (range 0–28). Similarly, in the pediatric cohort, median CD4 and CD8 counts at day 30 were 1500 and 2100/mcl, respectively, compared to 22 and 14 in a group of pts who did not receive d+2 ex-T, with no impact on engraftment. 1 adult and 3 pediatric pts also developed an “engraftment syndrome” characterized by GHVD-like features with or without fever. The adult pt with day 14 CD4 and CD8 counts of 2,724 and 11,571 cells/mcl had clinical and histologic features of (autologous) gut GVHD. 3 pediatric pts developed pruritic rashes clinically and pathologically indistiguishable from GVHD within 14 d of ex-T infusion, with fever seen in 1. In the adult and 1 pediatric pt, steroid treatment led to complete resolution of symptoms. These combined data sets demonstrate that robust CD4 and CD8 T cells counts can be achieved as early as day 14 post-SCT when adults or children receive ex-T at day +2 post-SCT without exogenous IL-2 or other cytokine support. It appears that a subset of patients develop a T cell “engraftment syndrome” similar to autologous GVHD. The mechanisms responsible for this rapid immune cell recovery are currently under investigation.

scholarly journals Alloantigen-activated (AAA) CD4+ T cells reinvigorate host endogenous T cell immunity to eliminate pre-established tumors in mice

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Kazuhiro Mochizuki ◽  
Shogo Kobayashi ◽  
Nobuhisa Takahashi ◽  
Kotaro Sugimoto ◽  
Hideki Sano ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Antitumor Immunity ◽  
Unmet Need ◽  
T Cell Response ◽  
Hematopoietic Stem ◽  
Cell Immunity ◽  
Allogeneic Lymphocytes

Abstract Background Cancer vaccines that induce endogenous antitumor immunity represent an ideal strategy to overcome intractable cancers. However, doing this against a pre-established cancer using autologous immune cells has proven to be challenging. “Allogeneic effects” refers to the induction of an endogenous immune response upon adoptive transfer of allogeneic lymphocytes without utilizing hematopoietic stem cell transplantation. While allogeneic lymphocytes have a potent ability to activate host immunity as a cell adjuvant, novel strategies that can activate endogenous antitumor activity in cancer patients remain an unmet need. In this study, we established a new method to destroy pre-developed tumors and confer potent antitumor immunity in mice using alloantigen-activated CD4+ (named AAA-CD4+) T cells. Methods AAA-CD4+ T cells were generated from CD4+ T cells isolated from BALB/c mice in cultures with dendritic cells (DCs) induced from C57BL/6 (B6) mice. In this culture, allogeneic CD4+ T cells that recognize and react to B6 mouse-derived alloantigens are preferentially activated. These AAA-CD4+ T cells were directly injected into the pre-established melanoma in B6 mice to assess their ability to elicit antitumor immunity in vivo. Results Upon intratumoral injection, these AAA-CD4+ T cells underwent a dramatic expansion in the tumor and secreted high levels of IFN-γ and IL-2. This was accompanied by markedly increased infiltration of host-derived CD8+ T cells, CD4+ T cells, natural killer (NK) cells, DCs, and type-1 like macrophages. Selective depletion of host CD8+ T cells, rather than NK cells, abrogated this therapeutic effect. Thus, intratumoral administration of AAA-CD4+ T cells results in a robust endogenous CD8+ T cell response that destroys pre-established melanoma. This locally induced antitumor immunity elicited systemic protection to eliminate tumors at distal sites, persisted over 6 months in vivo, and protected the animals from tumor re-challenge. Notably, the injected AAA-CD4+ T cells disappeared within 7 days and caused no adverse reactions. Conclusions Our findings indicate that AAA-CD4+ T cells reinvigorate endogenous cytotoxic T cells to eradicate pre-established melanoma and induce long-term protective antitumor immunity. This approach can be immediately applied to patients with advanced melanoma and may have broad implications in the treatment of other types of solid tumors.

T Cell-Mediated Control of HCMV Infection in Pediatric Patients Receiving Hematopoietic Stem Cell Transplantation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 5087-5087
Author(s):  
Franco Locatelli ◽  
Daniele Lilleri ◽  
Laura Lozza ◽  
Giovanna Giorgiani ◽  
Piero De Stefano ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Count ◽  
Hcmv Infection ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Lymphoproliferative Response ◽  
Hematopoietic Stem ◽  
Cell Immunity

Abstract We are studying the development of HCMV-specific CD4+ and CD8+ T cell response after allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients. A new technique was developed to simultaneously detect HCMV-specific CD4+ and CD8+ effector T cells using HCMV-infected autologous dendritic cells as stimulators and intracellular staining of IFN-γ production by T cells. This prospective study is based on monthly determination of both HCMV-specific T cell number and in vitro lymphoproliferative response to crude HCMV antigen. Patients are routinely monitored for HCMV infection/reactivation in blood (by determination of either antigenemia or quantitation of viral DNA) and treated according to a strategy of pre-emptive therapy. So far, of 41 patients receiving HSCT from an HLA-identical related donor (n=18), unrelated donor (n=15) or a T cell-depleted HSCT from a haploidentical relative (n=8), 25 patients have reached day +180, while 16 patients completed a follow-up of 90 days. Among the 28 HCMV-seropositive HSCT recipients, 25 developed HCMV-specific CD4+ and CD8+ T-cell response within the first 60 days after transplantation. In these patients, absolute CD4+ T cell count increased over time, but remained lower than that of healthy controls also at later time points. By contrast, CD8+ T cells reached and maintained absolute levels comparable to those of controls already from day +60. At this time, HCMV-specific CD4+ T cell count was comparable to that of controls, while HCMV-specific CD8+ T cell count was higher than that of controls, with no significant change thereafter. On the other hand, in vitro lymphoproliferative response to HCMV antigen was detectable only in about one half of these patients, even at day +180. HCMV infection was detected in blood of 22 of the 25 patients in whom HCMV-specific T cells were present. It was either self-limiting (n=14) or in 8 patients required shorter ganciclovir course (median 7 days, range 5-14) than in the 3 HCMV seropositive patients who developed HCMV infection in the absence of specific immunity (median 67 days, range 42–82, p<0.001). No patient developed HCMV disease or late viral infections. Conversely, HCMV-specific response was detected in only 3/13 HCMV seronegative recipients (none of whom developing detectable HCMV infection in blood). In these patients, both absolute and HCMV-specific T cell counts were lower than those of both controls and HCMV-seropositive HSCT recipients. Our data suggest that effective HCMV-specific T cell immunity can promptly develop after HSCT (regardless of donor type or T-cell depletion of the graft), particularly in seropositive recipients in whom latent virus may be a major antigenic drive for rapid reconstitution of T cell compartment, especially of CD8+ lymphocytes. On the other hand, transfer of memory T cell immunity from seropositive donors to seronegative recipients does not appear to be always sufficient to permit detection of virus-specific lymphocytes in patient’s peripheral blood in the early period after the allograft, possibly also due to the lower chance of in vivo antigen stimulation. The frequent dissociation between IFN-γ production and lymphoproliferative response remains to be explained. Future studies could address modulation of antiviral intervention on the reconstitution of HCMV-specific T cell immune response.

Adoptive Transfer of Natural Killer (NK) Cells to Prevent Gvhd and Enhance GVT Effects After Allogeneic Hematopoietic Cell Transplantation (HCT): The Timing of Donor NK Cell Infusions Critically Impacts Transplant Outcome.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 786-786
Author(s):  
Andreas Lundqvist ◽  
Hisayuki Yokoyama ◽  
Richard W. Childs
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Progression ◽  
Nk Cells ◽  
Median Survival ◽  
Nk Cell ◽  
Cell Transplant ◽  
Hematopoietic Stem ◽  
Allogeneic Hct ◽  
The Impact

Abstract Abstract 786 Murine models have shown infusions of donor NK cells from hematopoietic stem cell transplant donors can prevent GVHD while simultaneously mediating a graft-vs-tumor (GVT) effect. Reduction of GVHD by alloreactive NK cells can be mediated indirectly through the eradication of host antigen presenting cells (APC) or directly by NK cell killing of alloreactive T cells. To assess how the timing of NK cell administration impacts these effects, donor NK cells from B10.d2 (H-2d) mice (1-2×106 cells) were infused into MHC-matched BALB/c (H-2d) recipients following lethal irradiation (950cGy) at one of the following time-points: 1) two days prior to a T cell replete (TR) HCT to target host APC or 2) at the time of a TR-HCT or 3) five days following a TR-HCT to target both host APC and in vivo primed alloreactive donor T cells. We also evaluated whether donor NK cells given on the day of a T cell deplete (TD) HCT could be used to prevent GVHD in mice that subsequently received a delayed donor lymphocyte infusion (DLI) given four days following HCT. Administration of donor NK cells two days prior to allogeneic TR-HCT did not result in a reduction of GVHD (figure). In contrast, the administration of NK cells given either at the time of a TR-HCT or five days following a TR-HCT reduced the incidence of GVHD (GVHD incidence 70% (p=0.2) and 40% (p=0.01) respectively) compared to controls that did not receive NK cells following a TR-HCT (GVHD incidence 100%). Similarly, mice that received a TD-HCT followed by a DLI on day four had a significantly lower incidence of GVHD when NK cells were infused on the day of transplantation compared to controls that did not receive donor NK cells (GVHD incidence 40% vs 100% respectively, p=0.01). Using bioluminescence imaging, we next investigated the impact of the timing of NK cell infusions on GVT effects in tumor bearing mice. Luciferase transduced RENCA tumors were injected intravenously into BALB/c mice ten days prior to allogeneic HCT. Tumor progression was significantly delayed in recipients of a TR-HCT when NK cells were infused on day five compared to when NK cells were infused two days prior to or at the same day of a TR-HCT (tumor doubling times 22.9 days, 7.6 days and 8.5 days respectively; p=0.03) (figure). This delay in tumor progression correlated with a significant improvement in overall survival; recipients of a TR-HCT given NK cells on day five had significantly longer survival compared to recipients of TR-HCT that did not receive NK cells (median survival 54±14 days vs 44±9; p=0.008), whereas infusion of NK cells prior to or concomitant with a TR-HCT did not significantly prolong survival (median survival 49±4 days and 50±12 days respectively; p=0.23). A comparable delay in tumor progression and longer survival was observed in mice that received a TD-HCT followed by a DLI on day four when NK cells were infused at the time of transplant compared to controls not receiving NK cells (tumor doubling time 19.7 days vs 7.2 days and survival 62±16 days vs. 50±9 days respectively; p=0.07). In conclusion, these results show that the timing of adoptive donor NK cell transfer has a critical impact on the ability of NK cells to prevent GVHD and enhance GVT effects following both T-cell replete and T-cell depleted allogeneic HCT. Following a TR-HCT, a delayed add-back of NK cells maximizes GVHD reducing and anti-tumor effects of adoptively transferred donor NK cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Mechanisms that allow vaccination against an oncolytic vesicular stomatitis virus-encoded transgene to enhance safety without abrogating oncolysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amanda W. K. AuYeung ◽  
Robert C. Mould ◽  
Ashley A. Stegelmeier ◽  
Jacob P. van Vloten ◽  
Khalil Karimi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vesicular Stomatitis Virus ◽  
Cell Response ◽  
Viral Infections ◽  
T Cell Response ◽  
Oncolytic Viruses ◽  
Oncolytic Virotherapy ◽  
Cell Immunity ◽  
Vesicular Stomatitis

AbstractVaccination can prevent viral infections via virus-specific T cells, among other mechanisms. A goal of oncolytic virotherapy is replication of oncolytic viruses (OVs) in tumors, so pre-existing T cell immunity against an OV-encoded transgene would seem counterproductive. We developed a treatment for melanomas by pre-vaccinating against an oncolytic vesicular stomatitis virus (VSV)-encoded tumor antigen. Surprisingly, when the VSV-vectored booster vaccine was administered at the peak of the primary effector T cell response, oncolysis was not abrogated. We sought to determine how oncolysis was retained during a robust T cell response against the VSV-encoded transgene product. A murine melanoma model was used to identify two mechanisms that enable this phenomenon. First, tumor-infiltrating T cells had reduced cytopathic potential due to immunosuppression. Second, virus-induced lymphopenia acutely removed virus-specific T cells from tumors. These mechanisms provide a window of opportunity for replication of oncolytic VSV and rationale for a paradigm change in oncolytic virotherapy, whereby immune responses could be intentionally induced against a VSV-encoded melanoma-associated antigen to improve safety without abrogating oncolysis.

scholarly journals Impact of Different T Cell Depletion Protocols on Immune Reconstitution Following Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 43-44
Author(s):  
Amandine Pradier ◽  
Adrien Petitpas ◽  
Anne-Claire Mamez ◽  
Federica Giannotti ◽  
Sarah Morin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Reconstitution ◽  
Cell Depletion ◽  
Unrelated Donor ◽  
T Cell Depletion ◽  
Hematopoietic Stem ◽  
Post Transplant ◽  
The Impact

Introduction Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established therapeutic modality for a variety of hematological malignancies and congenital disorders. One of the major complications of the procedure is graft-versus-host-disease (GVHD) initiated by T cells co-administered with the graft. Removal of donor T cells from the graft is a widely employed and effective strategy to prevent GVHD, although its impact on post-transplant immune reconstitution might significantly affect anti-tumor and anti-infectious responses. Several approaches of T cell depletion (TCD) exist, including in vivo depletion using anti-thymocyte globulin (ATG) and/or post-transplant cyclophosphamide (PTCy) as well as in vitro manipulation of the graft. In this work, we analyzed the impact of different T cell depletion strategies on immune reconstitution after allogeneic HSCT. Methods We retrospectively analysed data from 168 patients transplanted between 2015 and 2019 at Geneva University Hospitals. In our center, several methods for TCD are being used, alone or in combination: 1) In vivo T cell depletion using ATG (ATG-Thymoglobulin 7.5 mg/kg or ATG-Fresenius 25 mg/kg); 2) in vitro partial T cell depletion (pTCD) of the graft obtained through in vitro incubation with alemtuzumab (Campath [Genzyme Corporation, Cambridge, MA]), washed before infusion and administered at day 0, followed on day +1 by an add-back of unmanipulated grafts containing about 100 × 106/kg donor T cells. The procedure is followed by donor lymphocyte infusions at incremental doses starting with 1 × 106 CD3/kg at 3 months to all patients who had received pTCD grafts with RIC in the absence of GVHD; 3) post-transplant cyclophosphamide (PTCy; 50 mg/kg) on days 3 and 4 post-HSCT. Absolute counts of CD3, CD4, CD8, CD19 and NK cells measured by flow cytometry during the first year after allogeneic HSCT were analyzed. Measures obtained from patients with mixed donor chimerism or after therapeutic DLI were excluded from the analysis. Cell numbers during time were compared using mixed-effects linear models depending on the TCD. Multivariable analysis was performed taking into account the impact of clinical factors differing between patients groups (patient's age, donor type and conditioning). Results ATG was administered to 77 (46%) patients, 15 (9%) patients received a pTCD graft and 26 (15%) patients received a combination of both ATG and pTCD graft. 24 (14%) patients were treated with PTCy and 26 (15%) patients received a T replete graft. 60% of patients had a reduced intensity conditioning (RIC). 48 (29%) patients received grafts from a sibling identical donor, 94 (56%) from a matched unrelated donor, 13 (8%) from mismatched unrelated donor and 13 (8%) received haploidentical grafts. TCD protocols had no significant impact on CD3 or CD8 T cell reconstitution during the first year post-HSCT (Figure 1). Conversely, CD4 T cells recovery was affected by the ATG/pTCD combination (coefficient ± SE: -67±28, p=0.019) when compared to the T cell replete group (Figure 1). Analysis of data censored for acute or chronic GVHD requiring treatment or relapse revealed a delay of CD4 T cell reconstitution in the ATG and/or pTCD treated groups on (ATG:-79±27, p=0.004; pTCD:-100±43, p=0.022; ATG/pTCD:-110±33, p&lt;0.001). Interestingly, pTCD alone or in combination with ATG resulted in a better reconstitution of NK cells compared to T replete group (pTCD: 152±45, p&lt;0.001; ATG/pTCD: 94±36, p=0.009; Figure 1). A similar effect of pTCD was also observed for B cells (pTCD: 170±48, p&lt;.001; ATG/pTCD: 127±38, p&lt;.001). The effect of pTCD on NK was confirmed when data were censored for GVHD and relapse (pTCD: 132±60, p=0.028; ATG/pTCD: 106±47, p=0.023) while only ATG/pTCD retained a significant impact on B cells (102±49, p=0.037). The use of PTCy did not affect T, NK or B cell reconstitution when compared to the T cell replete group. Conclusion Our results indicate that all TCD protocols with the only exception of PTCy are associated with a delayed recovery of CD4 T cells whereas pTCD of the graft, alone or in combination with ATG, significantly improves NK and B cell reconstitution. Figure 1 Disclosures No relevant conflicts of interest to declare.

scholarly journals Peptide vaccination directed against IDO1-expressing immune cells elicits CD8+ and CD4+ T-cell-mediated antitumor immunity and enhanced anti-PD1 responses

2020 ◽  
Vol 8 (2) ◽  
pp. e000605
Author(s):  
Souvik Dey ◽  
Erika Sutanto-Ward ◽  
Katharina L Kopp ◽  
James DuHadaway ◽  
Arpita Mondal ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Mhc Class I ◽  
Adoptive Transfer ◽  
Immune Cells ◽  
Class Ii ◽  
T Cell Response ◽  
Class I ◽  
Antitumor Effects

BackgroundThe tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase 1 (IDO1), which subverts T-cell immunity at multiple levels, is itself subject to inherent T-cell reactivity. This intriguing deviation from central tolerance has been interpreted as counterbalancing IDO1-mediated immunosuppression. Based on this hypothesis, clinical studies employing an IDO1 peptide-based vaccine approach for cancer treatment have been initiated, but there remains a pressing need to further investigate the immunological ramifications of stimulating the anti-IDO1 T-cell response in this manner.MethodsCT26 colon carcinoma tumors were evaluated for expression of IDO1 protein by western blot analysis, immunofluorescence microscopy and flow cytometry. Mouse IDO1-derived peptides, predicted to bind either major histocompatibility complex (MHC) class I or II of the H2d BALB/c strain, were emulsified in 50% Montanide for prophylactic or therapeutic vaccine treatment of CT26 tumor-bearing mice initiated either 7 days prior to or following tumor cell injection, respectively. In some therapeutic treatment experiments, administration of programmed cell death protein 1-binding antibody (anti-PD1 antibody) or epacadostat was concurrently initiated. Tumor size was determined by caliper measurements and comparative tumor growth suppression was assessed by longitudinal analyses of tumor growth data. For adoptive transfer, T cells from complete responder animals were isolated using paramagnetic beads and fluorescence-activated cell sorting.ResultsThis study identifies mouse MHC class I-directed and II-directed, IDO1-derived peptides capable of eliciting antitumor responses, despite finding IDO1 expressed exclusively in tumor-infiltrating immune cells. Treatment of established tumors with anti-PD1 antibody and class I-directed but not class II-directed IDO1 peptide vaccines produced an enhanced antitumor response. Likewise, class I-directed and II-directed IDO1 peptides elicited an enhanced combinatorial response, suggesting distinct mechanisms of action. Consistent with this interpretation, adoptive transfer of isolated CD8+ T cells from class I and CD4+ T cells from class II peptide-vaccinated responder mice delayed tumor growth. The class II-directed response was completely IDO1-dependent while the class I-directed response included an IDO1-independent component consistent with antigen spread.ConclusionsThe in vivo antitumor effects demonstrated with IDO1-based vaccines via targeting of the tumor microenvironment highlight the utility of mouse models for further exploration and refinement of this novel vaccine-based approach to IDO1-directed cancer therapy and its potential to improve patient response rates to anti-PD1 therapy.

scholarly journals TCR Repertoire Characterization for T Cells Expanded in Response to hRSV Infection in Mice Immunized with a Recombinant BCG Vaccine

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 233
Author(s):  
Emma Rey-Jurado ◽  
Karen Bohmwald ◽  
Hernán G. Correa ◽  
Alexis M. Kalergis
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Response ◽  
Bcg Vaccine ◽  
Lung Damage ◽  
Cell Repertoire ◽  
Cell Immunity ◽  
Tcr Repertoire ◽  
Syncytial Virus

T cells play an essential role in the immune response against the human respiratory syncytial virus (hRSV). It has been described that both CD4+ and CD8+ T cells can contribute to the clearance of the virus during an infection. However, for some individuals, such an immune response can lead to an exacerbated and detrimental inflammatory response with high recruitment of neutrophils to the lungs. The receptor of most T cells is a heterodimer consisting of α and β chains (αβTCR) that upon antigen engagement induces the activation of these cells. The αβTCR molecule displays a broad sequence diversity that defines the T cell repertoire of an individual. In our laboratory, a recombinant Bacille Calmette–Guérin (BCG) vaccine expressing the nucleoprotein (N) of hRSV (rBCG-N-hRSV) was developed. Such a vaccine induces T cells with a Th1 polarized phenotype that promote the clearance of hRSV infection without causing inflammatory lung damage. Importantly, as part of this work, the T cell receptor (TCR) repertoire of T cells expanded after hRSV infection in naïve and rBCG-N-hRSV-immunized mice was characterized. A more diverse TCR repertoire was observed in the lungs from rBCG-N-hRSV-immunized as compared to unimmunized hRSV-infected mice, suggesting that vaccination with the recombinant rBCG-N-hRSV vaccine triggers the expansion of T cell populations that recognize more viral epitopes. Furthermore, differential expansion of certain TCRVβ chains was found for hRSV infection (TCRVβ+8.3 and TCRVβ+5.1,5.2) as compared to rBCG-N-hRSV vaccination (TCRVβ+11 and TCRVβ+12). Our findings contribute to better understanding the T cell response during hRSV infection, as well as the functioning of a vaccine that induces a protective T cell immunity against this virus.

scholarly journals Direct evidence for new T-cell generation by patients after either T-cell–depleted or unmodified allogeneic hematopoietic stem cell transplantations

Blood ◽  
2002 ◽  
Vol 100 (6) ◽  
pp. 2235-2242 ◽  
Author(s):  
Sharon R. Lewin ◽  
Glenn Heller ◽  
Linqi Zhang ◽  
Elaine Rodrigues ◽  
Eva Skulsky ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell ◽  
Opportunistic Infections ◽  
Cell Receptor ◽  
Hematopoietic Stem ◽  
Cell Immunity ◽  
The Difference ◽  
T Cell Phenotypes

Abstract Successful allogeneic hematopoietic stem cell transplantation (HSCT) requires reconstitution of normal T-cell immunity. Recipient thymic activity, biologic features of the allograft, and preparative regimens all contribute to immune reconstitution. We evaluated circulating T-cell phenotypes and T-cell receptor rearrangement excision circles (TRECs) in 331 blood samples from 158 patients who had undergone allogeneic HSCTs. All patients had received myeloablative conditioning regimens and were full donor chimeras in remission. Younger patients exhibited more rapid recovery and higher TRECs (P = .02). Recipients of T-cell–depleted allografts initially had lower TRECs than unmodified allograft recipients (P < .01), but the difference abated beyond 9 months. TREC level disparities did not achieve significance among adults with respect to type of allograft. Measurable, albeit low, TREC values correlated strongly with severe opportunistic infections (P < .01). This finding was most notable during the first 6 months after transplantation, when patients are at greatest risk but before cytofluorography can detect circulating CD45RA+ T cells. Low TRECs also correlated strongly with extensive chronic graft-versus-host disease (P < .01). Recipients of all ages of either unmodified or T-cell–depleted allografts therefore actively generate new T cells. This generation is most notable among adult recipients of T-cell–depleted allografts, most of whom had also received antithymocyte globulin for rejection prophylaxis. Low TREC values are significantly associated with morbidity and mortality after transplantation. T-cell neogenesis, appropriate to age but delayed in adult recipients of T-cell– depleted allografts, justifies interventions to hasten this process and to stimulate desirable cellular immune responses.

scholarly journals CD8+-T-Cell Response to Secreted and Nonsecreted Antigens Delivered by Recombinant Listeria monocytogenes during Secondary Infection

2002 ◽  
Vol 70 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Amy R. Tvinnereim ◽  
Sara E. Hamilton ◽  
John T. Harty
Keyword(s):  
T Cells ◽  
Listeria Monocytogenes ◽  
T Cell ◽  
Cell Response ◽  
Low Dose ◽  
Recombinant Antigen ◽  
T Cell Response ◽  
Vector System ◽  
High Dose ◽  
The Impact

ABSTRACT Understanding how existing antivector immunity impacts live vaccine delivery systems is critical when the same vector system may be used to deliver different antigens. We addressed the impact of antivector immunity, elicited by immunization with attenuated actA-deficient Listeria monocytogenes, on the CD8+-T-cell response to a well-characterized lymphocytic choriomeningitis virus epitope, NP118-126, delivered by infection with recombinant L. monocytogenes. Challenges of immune mice with actA-deficient and with wild-type recombinant L. monocytogenes generated similar numbers of CD8+ T cells specific for the NP118-126 epitope. High-dose immunization with actA-deficient L. monocytogenes resulted in substantial numbers of CD8+ T cells specific for the L. monocytogenes LLO91-99 epitope in the effector and memory stages of the T-cell response. Challenge of these immune mice with recombinant L. monocytogenes resulted in rapid control of the infection and decreased CD8+-T-cell responses against both the secreted and nonsecreted form of the recombinant antigen compared to the response of naïve mice. In contrast, mice immunized with a low dose of actA-deficient L. monocytogenes had ∼10-fold fewer effector and memory T cells specific for LLO91-99 and a substantially higher CD8+-T-cell response against the recombinant antigen after challenge with recombinant L. monocytogenes. Although mice immunized with low-dose actA-deficient L. monocytogenes had a substantial recall response to LLO91-99, which reached the same levels by 5 to 7 days postchallenge as that in high-dose-immunized mice, they exhibited decreased ability to control L. monocytogenes replication. Thus, the level of antivector immunity impacts the control of infection and efficiency of priming responses against new antigens introduced with the same vector.

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