Recombinant adenovirus vaccines can successfully elicit CD8+ T cell immunity under conditions of extreme leukopenia (original) (raw)
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Human AdV-specific T cells: persisting in vitro functionality despite lethal irradiation
Bone marrow transplantation, 2014
Viral infections caused by human adenovirus (HAdV) or CMV remain life-threatening complications in immunocompromised patients undergoing allogeneic hematopoietic stem cell transplantation. Adoptive immunotherapy with virus-specific T cells showed impressive clinical results without or with only mild GvHD. However, because of high costs and high regulatory barriers, these protocols are accessible to only a few centers. The infusion of unmanipulated donor lymphocytes (DLIs) that contain virus-specific T cells is not feasible because of the risk of GvHD. Reports about three patients treated with irradiated granulocytes or DLIs that potentially comprised virus-specific T cells discussed an active role of virus-specific lymphocytes despite irradiation, but real evidence could not be provided. Therefore, we tested the effect of irradiation on HAdV-specific T cells, which had been expanded in vitro, by stimulating PBMCs with HAdV-peptide pools and IL-15 for 12 days. Cells were then irradia...
On the Role of CD4+ T Cells in the CD8+ T-Cell Response Elicited by Recombinant Adenovirus Vaccines
Molecular Therapy, 2007
We have investigated the role of CD4 + T cells in the development of the CD8 + T-cell response after immunization with recombinant adenovirus (rAd). In the absence of CD4 + T cells, the "unhelped" CD8 + T-cell population exhibited a reduction in primary expansion and long-term survival that appeared to be due to inadequate priming of naïve T cells. There were few functional or phenotypic differences between the helped and unhelped CD8 + T-cell populations with the exception of O-glycosylated CD43, a marker of effector cells, which was augmented on the unhelped CD8 + T-cell population. In some cases, the unhelped CD8 + T-cell population exhibited reduced ability to control virus infection; however, this appeared to be a function of the reduced frequency of antigenspecific CD8 + T cells. Most notably, the unhelped CD8 + T-cell population exhibited no defect in secondary expansion. These results provide insight into the role of CD4 + T cells during the primary CD8 + T-cell response generated by rAd vaccines and identify potential benefits and issues that must be considered when using adenovirus vaccines under conditions where CD4 + T-cell function may be limiting, such as vaccination of human immunodeficiency virus patients.
Experimental Hematology, 2010
Objective. In lethally irradiated bone marrow chimeras, part of the reconstituted T-cell compartment is derived from the irradiated host, but the detailed origin and functional activity of host-derived T cells has not been thoroughly analyzed. Herein, we determine the origin and function of radioresistant host-derived T cells. Materials and Methods. Lethally irradiated thymectomized or nonthymectomized C57BL/6 host mice were reconstituted with syngeneic bone marrow, itself incapable of generating T cells. Using fetal thymic organ cultures, bulk and limiting dilution assays on OP9-DL1 stromal cells, unambiguous cohorts of thymus-derived and peripheral T-cellLderived T cells were phenotypically characterized by flow cytometry and functionally characterized by their ability to participate in a T-cellLdependent antibody response.
The Journal of Immunology, 2006
We have previously reported that the CD8 ؉ T cell response elicited by recombinant adenovirus vaccination displayed a delayed contraction in the spleen. In our current study, we demonstrate that this unusual kinetic is a general phenomenon observed in multiple tissues. Phenotypic analysis of transgene-specific CD8 ؉ T cells present 30 days postimmunization with recombinant adenovirus revealed a population with evidence of partial exhaustion, suggesting that the cells had been chronically exposed to Ag. Although Ag expression could no longer be detected 3 wk after immunization, examination of Ag presentation within the draining lymph nodes demonstrated that APCs were loaded with Ag peptide for at least 40 days postimmunization, suggesting that Ag remains available to the system for a prolonged period, although the exact source of this Ag remains to be determined. At 60 days postimmunization, the CD8 ؉ T cell population continued to exhibit a phenotype consistent with partially exhausted effector memory cells. Nonetheless, these CD8 ؉ T cells conferred sterilizing immunity against virus challenge 7-12 wk postimmunization, suggesting that robust protective immunity can be provided by CD8 ؉ T cells with an exhausted phenotype. These data demonstrate that prolonged exposure to Ag may not necessarily impair protective immunity and prompt a re-evaluation of the impact of persistent exposure to Ag on T cell function.
European Journal of Immunology, 2003
To test whether homeostasis-driven T cell proliferation in reconstituted lymphodepleted hosts would improve the therapeutic efficacy of tumor vaccines, normal mice and reconstituted lymphopenic mice (RLM; C57BL/6 mice rendered lymphopenic with sublethal total-body irradiation and reconstituted with naive splenocytes) were used in the vaccination and challenge experiments with weakly immunogenic F10 melanoma cells. Only limited protection was observed in vaccinated normal mice (16.7%), whereas significantly greater protection was induced in vaccinated RLM (63.2%). Protective immunity in RLM depended on CD8 T cells. Following vaccination, a significant increase in the percentage of CD44hiCD62Llo T cells was detected in the tumor vaccine-draining lymph node (TVDLN) of vaccinated RLM compared to that of vaccinated normal mice. After in vitro stimulation, effector T cells generated from TVDLN of vaccinated RLM produced more IFN-γ than T cells from vaccinated normal mice, and contained more melanoma-specific T cells, as assessed by ELISA and intracellular cytokine staining. This study suggests that vaccination of reconstituted lymphopenic hosts could elicit superior anti-tumor immunity compared to normal hosts, highlighting the potential clinical benefit of performing tumor vaccination during immune reconstitution.
Acta medica (Hradec Králové) / Universitas Carolina, Facultas Medica Hradec Králové, 2008
Experiments presented here were aimed at the description of hematopoiesis repair and in vivo homing of transplanted separated CD117+B220- bone marrow cells after whole-body lethal irradiation at LD 9Gy. ROSA 26 mice were used as donors of marrow cells for transplantation [B6;129S/Gt (ROSA)26Sor] and were tagged with lacZ gene, and F2 hybrid mice [B6129SF2/J] were used as recipients of bone marrow transplanted cells. Hematopoiesis repair was provided by transplantation, both suspension of whole bone marrow cells (5x106) and isolated CD117+B220- cells (5x10(4)). Mice survived up to thirty days after irradiation. We demonstrated that transplantation of suspension of whole bone marrow cells led to faster recovery of CFU-GM (Granulocyte-macrophage colony forming units) in bone marrow and in the spleen too. It is not clear what the share of residential and transplanted cells is in the repair process. Our results demonstrate that sufficient hematopoietic repair occurs after transplantation...
Apoptotic Response of Irradiated T-Lymphocytes
Strahlenther Onkol, 2003
Background: Evaluation of radiation-induced apoptosis in T-lymphocytes was developed for human medicine in order to predict the sensitivity of individual patients to radiation therapy and has regular use in cases of suspected hypersensitivity. A major goal of the present study was to evaluate the usefulness of the apoptosis assay in veterinary medicine for application in radiation sensitivity testing. The main goal was to examine potential changes in sensitivity of T-lymphocytes to radiation-induced apoptosis during the course of radiation treatment. This is a clear example of the advantageous use of spontaneous canine tumors to augment human cancer research. Material and Methods: Blood was collected in heparin tubes, diluted 1 : 10 in RPMI medium, irradiated with X-rays and incubated for 48 h. T-lymphocytes were labeled using FITC-conjugated antibodies, erythrocytes were lysed, and DNA stained with propidium iodide. For cell analysis, a Becton Dickinson FACScan flow cytometer was used. Radiation-induced apoptosis in T-lymphocytes was quantified. Blood samples from tumor-bearing dogs were taken before the first fraction and at the end of radiation therapy. Results: Apoptosis in lymphocytes is dependent on donor age and donor weight. Tumor-bearing dogs when compared with healthy dogs showed no significant differences in levels of induced apoptosis. No significant changes were seen in the levels of radiation-induced apoptosis in blood taken before, during, or after radiation therapy. Conclusion: The leukocyte apoptosis assay can be successfully applied to canine patients, and a wide spectrum of sensitivities to radiation-induced apoptosis is observed. The sensitivity of a patient's peripheral blood T-lymphocytes to radiation-induced apoptosis does not change as a result of the trauma of radiotherapy during the course of tumor treatment.
Molecular Therapy, 2008
Carcinoembryonic antigen (CEA) is strongly expressed in a vast majority of gastrointestinal carcinomas. Recently, epitope peptides of CEA were identified. We have demonstrated HLA-A24-restricted peptide, CEA652[9] (TYACFVSNL), was capable of eliciting specific cytotoxic T lymphocytes (CTLs) which could lyse tumor cells expressing HLA-A24 and CEA. HLA-A24 is the most applicable MHC class I allele in the Japanese population. In this pilot study, we have used the peptide-pulsed dendritic cells (DCs) generated from peripheral blood mononuclear cells (PBMCs) supplemented with GM-CSF and IL-4 as the source of the vaccine. Eight patients with advanced CEA-expressing gastrointestinal malignancies received subcutaneous injections every 2 or 3 weeks. Immunomonitoring was performed by ELISpot (enzyme-linked immunosorbent spot) assay to measure the precursor frequency of CTLs and their capacity to elicit antitumor CTLs in vitro. Four of seven patients have developed their CTL response after vaccinations. DTH reaction was observed in one of eight patients at the DC-injected site. Skin biopsy at the injected site showed the infiltration of the lymphocytes. Furthermore, A24/CEA peptide tetramer assay revealed an increase in peptide-specific T-cell precursor frequency in vaccinated patients. No significant toxic adverse effects were observed, except for mild diarrhea in one case after three vaccinations. Three patients have shown stabilization of the disease after vaccinations. In conclusion, our results clearly demonstrated that our vaccination protocol was safe and might develop a CEA-specific CTL response in cancer patients.