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Biomedical subjects

Cliona M Rooney

Publications and source records attributed to Cliona M Rooney.

At least 19 recordsLinked to original sources
PubMed2006

Monoculture-derived T lymphocytes specific for multiple viruses expand and produce clinically relevant effects in immunocompromised individuals.

Immunocompromised individuals are at high risk for life-threatening diseases, especially those caused by cytomegalovirus (CMV), Epstein-Barr virus (EBV) and adenovirus. Conventional therapeutics are primarily active only against CMV, and resistance is frequent. Adoptive transfer of polyclonal cytotoxic T lymphocytes (CTLs) specific for CMV or EBV seems promising, but it is unclear whether this strategy can be extended to adenovirus, which comprises many serotypes. In addition, the preparation of a specific CTL line for each virus in every eligible individual would be impractical. Here we describe genetic modification of antigen-presenting cell lines to facilitate the production of CD4(+) and CD8(+) T lymphocytes specific for CMV, EBV and several serotypes of adenovirus from a single cell culture. When administered to immunocompromised individuals, the single T lymphocyte line expands into multiple discrete virus-specific populations that supply clinically measurable antiviral activity. Monoculture-derived multispecific CTL infusion could provide a safe and efficient means to restore virus-specific immunity in the immunocompromised host.

Adenoviridae↗
PubMed2006

T lymphocytes redirected against the kappa light chain of human immunoglobulin efficiently kill mature B lymphocyte-derived malignant cells.

There has been interest in generating T cells expressing chimeric artificial receptors (CARs) targeting CD19/CD20 antigens to treat B-cell lymphomas. If successful, however, this approach would likely impair humoral immunity because T cells may persist long-term. Most low-grade lymphoma and chronic lymphocytic leukemia (B-CLL) cells express monoclonal immunoglobulins carrying either kappa or lambda light chains. We, therefore, explored whether T lymphocytes could be genetically modified to target the tumor-associated light chain, sparing B lymphocytes expressing the reciprocal light chain, and consequently reduce impairment of humoral immunity. We found that T lymphocytes expressing the anti-kappa light chain CAR showed cytotoxic activity against Igkappa(+) tumor cell lines and B-CLL cells both in vitro and in vivo. We also found that the incorporation of the CD28 endodomain within the CAR enhanced the in vitro and in vivo expansion of transgenic T cells after tumor-associated antigen stimulation. Free Igkappa(+) did not compromise the ability of redirected T lymphocytes to eliminate Igkappa(+) tumors because these free immunoglobulins served to sustain proliferation of CAR-CD28 transgenic T cells. Thus, adoptive transfer of T lymphocytes targeting the appropriate light chain could be a useful immunotherapy approach to treat B-lymphocyte malignancies that clonally express immunoglobulin without entirely compromising humoral immunity.

Adoptive Transfer↗
PubMed2006

Treatment of solid organ transplant recipients with autologous Epstein Barr virus-specific cytotoxic T lymphocytes (CTLs).

We have investigated the in vivo safety, efficacy, and persistence of autologous Epstein Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) for the treatment of solid organ transplant (SOT) recipients at high risk for EBV-associated posttransplantation lymphoproliferative disease (PTLD). EBV-CTLs generated from 35 patients expanded with normal kinetics contained both CD8 and CD4 lymphocytes and produced significant specific killing of autologous EBV-transformed B lymphoblastoid cell lines (LCLs). Twelve SOT recipients at high risk for PTLD, or with active disease, received autologous CTL infusions without toxicity. Real-time polymerase chain reaction (PCR) monitoring of EBV-DNA showed a transient increase in plasma EBV-DNA suggestive of lysis of EBV-infected cells, although there was no consistent decrease in virus load in peripheral-blood mononuclear cells. Interferon-gamma enzyme-linked immunospot (ELISPOT) assay and tetramer analysis showed an increase in the frequency of EBV-responsive T cells, which returned to preinfusion levels after 2 to 6 months. None of the treated patients developed PTLD. One patient with liver PTLD showed a complete response, and one with ocular disease has had a partial response stable for over one year. These data are consistent with an expansion and persistence of adoptively transferred EBV-CTLs that is limited in the presence of continued immunosuppression but that nonetheless produces clinically useful antiviral activity.

Antigens, Viral↗
PubMed2006

Adenoviral infections in hematopoietic stem cell transplantation.

Adenoviruses are lytic DNA viruses that are ubiquitous in human communities. In total, 51 different serotypes with varying tissue tropisms have been identified. Adenovirus infections, although frequent, are rarely fatal in immunocompetent individuals who have potent innate and adaptive immunity. But in immunosuppressed individuals, adenoviruses are a significant cause of morbidity and mortality, with limited treatment options. In particular, pediatric recipients of allogeneic hematopoietic stem cell transplantation frequently develop infections early in the posttransplantation period. Because the endogenous recovery of adenovirus-specific T cells has proven important in controlling infection, we explore the potential of adoptive T-cell immunotherapy as a therapeutic strategy. We discuss the advantages and limitations of T-cell therapy for the prophylaxis and treatment of adenovirus infection posttransplantation.

Adenoviridae Infections↗
PubMed2006

In vivo expansion of LMP 1- and 2-specific T-cells in a patient who received donor-derived EBV-specific T-cells after allogeneic stem cell transplantation.

Immunotherapy approaches with antigen-specific cytotoxic T lymphocytes (CTLs) have provided safe and effective prophylaxis and treatment of Epstein-Barr virus (EBV)-associated lymphomas arising after bone marrow transplantation. EBV is also associated with other malignancies including approximately 40% of cases of Hodgkin's disease, making this tumor another potential target for EBV-targeted immunotherapy. This study describes a patient with multiple relapsed EBV positive Hodgkin's Disease who received both autologous and allogeneic EBV CTL lines. After multiple chemotherapeutic and radiotherapy regimens including two autologous stem cell transplants, he received two doses of gene-marked autologous EBV-specific CTL which resulted in disease stabilization for 6 months. The gene-marked EBV-CTL persisted for 12 months in the peripheral blood after which he proceeded to unrelated donor stem cell transplant followed by immunotherapy with donor-derived EBV-specific CTL. Despite low levels of donor chimerism, the patient remains in complete remission 5 years post-allogeneic SCT. Comparison of the autologous and the donor-derived CTL lines showed that the donor line had specificity for two tumor-associated EBV antigens, latent membrane protein (LMP)1 and 2 compared to the autologous line, which only had specificity for LMP2 epitopes. Following infusion of the donor-derived CTL, functional analyses showed that T-cells reactive with both LMP1 and LMP2 epitopes expanded in the peripheral blood, suggesting that strategies to increase their frequency may result in a broader cytotoxic response against EBV+ Hodgkin tumors.

Cell Proliferation↗
PubMed2006

Improving T cell therapy for cancer.

Adoptive transfer of antigen-specific T cells has been most effective in treating cytomegalovirus (CMV) disease and Epstein-Barr virus (EBV)-associated lymphoproliferative disease (LPD). Both of these diseases develop only during periods of acute immune suppression, and both involve highly immunogenic infected cells, and thus respond well to T cell therapies. In contrast, tumours that develop in the presence of a competent immune system evolve complex immune evasion strategies to avoid and subvert T cell-mediated killing. Therefore, even T cells that display potent cytotoxic activity against tumour cells in vitro may not be effective in vivo without altering the tumour:T cell balance in favour of the T cell. This review discusses several new areas of research aimed at improving adoptive T cell therapy for the treatment of cancer, including the genetic modification of antigen-specific T cells to allow them to perform better in vivo, and conditioning the host to improve in vivo expansion and function of transferred cells.

Animals↗
PubMed2006

Adoptive immunotherapy for Hodgkin's lymphoma.

Adoptive transfer of tumor-specific T-cells is an attractive strategy for the treatment of patients with refractory or relapsed Hodgkin's lymphoma. However, Hodgkin's lymphomas possess a range of tumor-evasion mechanisms, which must be overcome before the full potential of immunotherapies can be achieved. In this article, we discuss the promise of Epstein-Barr virus-specific cytotoxic T-lymphocytes, the roles of cytokines, and other strategies for overcoming the immune-evasion mechanisms in Hodgkin's lymphoma.

Cytokines↗
PubMed2005

Characterization of latent membrane protein 2 specificity in CTL lines from patients with EBV-positive nasopharyngeal carcinoma and lymphoma.

Viral proteins expressed by EBV-associated tumors provide target Ags for immunotherapy. Adoptive T cell therapy has proven effective for posttransplant EBV-associated lymphoma in which all EBV latent Ags are expressed (type III latency). Application of immunotherapeutic strategies to tumors such as nasopharyngeal carcinoma and Hodgkin's lymphoma that have a restricted pattern of EBV Ag expression (type II latency) is under investigation. Potential EBV Ag targets for T cell therapy expressed by these tumors include latent membrane proteins (LMP) 1 and 2. A broad panel of epitopes must be identified from these target Ags to optimize vaccination strategies and facilitate monitoring of tumor-specific T cell populations after immunotherapeutic interventions. To date, LMP2 epitopes have been identified for only a limited number of HLA alleles. Using a peptide library spanning the entire LMP2 sequence, 25 CTL lines from patients with EBV-positive malignancies expressing type II latency were screened for the presence of LMP2-specific T cell populations. In 21 of 25 lines, T cell responses against one to five LMP2 epitopes were identified. These included responses to previously described epitopes as well as to newly identified HLA-A*0206-, A*0204/17-, A29-, A68-, B*1402-, B27-, B*3501-, B53-, and HLA-DR-restricted epitopes. Seven of the nine newly identified epitopes were antigenically conserved among virus isolates from nasopharyngeal carcinoma tumors. These new LMP2 epitopes broaden the diversity of HLA alleles with available epitopes, and, in particular, those epitopes conserved between EBV strains provide valuable tools for immunotherapy and immune monitoring.

Epitopes, T-Lymphocyte↗
PubMed2005

A chimeric T cell antigen receptor that augments cytokine release and supports clonal expansion of primary human T cells.

The transduction of primary T cells to express chimeric T cell receptors (cTCR) for redirected targeting of tumor cells is an attractive strategy for generating tumor-specific T cells for adoptive therapy. However, tumor cells rarely provide costimulatory signals and hence cTCRs that transmit just a CD3zeta signal can only initiate target cell killing and interferon-gamma release and fail to induce full activation. Although incorporation of a CD28 component results in IL-2 release and limited proliferation, T cell activation remains incomplete. OX40 transmits a potent and prolonged T cell activation signal and is crucial for maintaining an immunological response. We hypothesize that the CD28-OX40-CD3zeta tripartite cytoplasmic domain will provide a full complement of activation, proliferation, and survival signals for enhanced anti-tumor activity.

CD28 Antigens↗
PubMed2005

An inducible caspase 9 safety switch for T-cell therapy.

The efficacy of adoptive T-cell therapy as treatment for malignancies may be enhanced by genetic modification of infused cells. However, oncogenic events due to vector/transgene integration, and toxicities due to the infused cells themselves, have tempered enthusiasm. A safe and efficient means of removing aberrant cells in vivo would ameliorate these concerns. We describe a "safety switch" that can be stably and efficiently expressed in human T cells without impairing phenotype, function, or antigen specificity. This reagent is based on a modified human caspase 9 fused to a human FK506 binding protein (FKBP) to allow conditional dimerization using a small molecule pharmaceutical. A single 10-nM dose of synthetic dimerizer drug induces apoptosis in 99% of transduced cells selected for high transgene expression in vitro and in vivo. This system has several advantages over currently available suicide genes. First, it consists of human gene products with low potential immunogenicity. Second, administration of dimerizer drug has no effects other than the selective elimination of transduced T cells. Third, inducible caspase 9 maintains function in T cells overexpressing antiapoptotic molecules. These characteristics favor incorporation of inducible caspase 9 as a safety feature in human T-cell therapies.

Animals↗
PubMed2005

Human cytotoxic T lymphocytes with reduced sensitivity to Fas-induced apoptosis.

Effector-memory T cells expressing Fas (Apo-1/CD95) are switched to an apoptotic program by cross-linking with Fas-ligand (FasL). Consequently, tumors that express FasL can induce apoptosis of infiltrating Fas-positive T lymphocytes and subdue any antitumor host immune response. Since Epstein-Barr virus (EBV)-associated tumors such as Hodgkin lymphoma (HL) and nasopharyngeal carcinoma (NPC) express FasL, we determined whether EBV-specific cytotoxic T lymphocytes (EBV-CTLs) could be modified to resist this evasion strategy. We show that long-term down-modulation of Fas can be achieved in EBV-CTLs by transduction with small interfering RNA (siRNA) encoded in a retrovirus. Modified T cells resisted Fas/FasL-mediated apoptosis compared with control cells and showed minimal cleavage of the caspase3 substrate poly(ADP-ribose) polymerase (PARP) protein after Fas engagement. Prolonged Fas stimulation selected a uniformly Fas(low) and FasL resistant population. Removal of responsiveness to this single death signal had no other discernible effects on EBV-CTLs. In particular, it did not lead to their autonomous growth since the modified EBV-CTLs remained polyclonal, and their survival and proliferation retained dependence on antigen-specific stimulation and on the presence of other physiologic growth signals. EBV-CTLs with knocked down Fas should have a selective functional and survival advantage over unmodified EBV-CTLs in the presence of tumors expressing FasL and may be of value for adoptive cellular therapy.

Animals↗
PubMed2005

HLA type-independent generation of antigen-specific T cells for adoptive immunotherapy.

Adoptive immunotherapy with antigen-specific T cells has been successfully used to treat certain infectious diseases and cancers. Although more patients may profit from T cell therapy, its more frequent use is restricted by limitations in current T cell generation strategies. The most commonly applied peptide-based approaches rely on the knowledge of relevant epitopes. Therefore, T cells cannot be generated for diseases with unknown epitopes or for patients with unfavorable HLA types. We developed a peptide-based approach for HLA type-independent generation of specific T cells against various proteins. It is based on short-time stimulation with peptide libraries that cover most CD4(+) and CD8(+) T cell epitopes of given proteins. The procedure requires no prior knowledge of epitopes because libraries are synthesized solely on the basis of the protein's amino acid sequence. Stimulation is followed by immunomagnetic selection of activated IFN-gamma-secreting cells and nonspecific expansion. To evaluate the protocol, we generated autologous T cells specific for a well-characterized antigen, the human cytomegalovirus phosphoprotein 65 (pp65). Generated T cell lines consisted of pp65-specific CD4(+) and CD8(+) lymphocytes that displayed antigen-specific killing and proliferation. The protocol combines the biosafety of peptide-based approaches with HLA type independence and may help to advance adoptive immunotherapy in the future.

Cell Proliferation↗
PubMed2005

Adoptive immunotherapy for EBV-associated malignancies.

Latent Epstein-Barr virus (EBV) infection is associated with a diverse group of malignancies including Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma (NPC), and lymphoproliferative disease (LPD). EBV proteins expressed in these malignancies provide targets for the adoptive immunotherapy with antigen-specific cytotoxic T cells (CTL) and EBV-specific CTL have been used successfully for the prophylaxis and treatment of EBV-LPD post hematopoietic stem cell transplantation (HSCT). The clinical experience with EBV-specific CTL for other EBV-associated malignancies such as Hodgkin's disease and NPC is limited and the results obtained so far indicate that EBV-specific CTL are less effective than for EBV-LPD post HSCT. Decreased CTL efficacy most likely reflect immune evasion strategies by tumor cells such as down regulation of immunodominant EBV proteins and secretion of inhibitory cytokines. To overcome these immune evasion strategies a number of approaches have been developed including targeting CTL to subdominant EBV antigens and genetically modifying CTL to increase their potency.

Epstein-Barr Virus Infections↗
PubMed2005

Adenovirus as an emerging pathogen in immunocompromised patients.

Adenoviruses are non-enveloped, lytic, DNA viruses capable of infecting most animal species. There are 51 different human adenovirus serotypes, which are grouped from A to F on the basis of genome size, composition, homology and organization. Pathogenicity varies according to group and type, but infections are generally well controlled by the host immune system in immunocompetent individuals. However, in the immunosuppressed, adenoviral infections are a frequent cause of morbidity and mortality. To date there is no effective therapy. Adoptive transfer of immune T cells offers a therapeutic option, but this strategy has been hindered by the lack of information on targets of protective cellular immunity, and by the immunological heterogeneity of the 51 human adenoviruses. Nevertheless, until such an approach is implemented, or an effective antiviral agent becomes commercially available, it is likely that adenovirus infections will continue to be responsible for a significant number of virus-associated deaths each year.

Adenoviridae↗
PubMed2005

Cellular immunity to Epstein-Barr virus in liver transplant recipients treated with rituximab for post-transplant lymphoproliferative disease.

The evaluation of long-term cellular immunity to EBV in pediatric orthotopic liver transplant (OLT) recipients after treatment with the humanized anti-CD20 monoclonal antibody (Rituximab) has not yet been explored. At our institution, one child with EBV-related mononucleosis-like syndrome and five children with polymorphic-EBV-PTLD occurring 6-88 months after OLT were treated with Rituximab. Treatment was well tolerated. All children achieved complete remission. After Rituximab, B-lymphocytes were undetectable in the peripheral blood and EBV-load, monitored with real-time PCR, decreased to undetectable levels in all children from >4000 copies/microg DNA at diagnosis. Four to eight months after Rituximab, EBV-load increased (>4000 copies/microg DNA) in four children, and PTLD recurred in three. Their frequency of EBV-specific T-cell precursors, measured by Elispot analysis, remained lower than in healthy controls. Rituximab effectively induced regression of PTLD in OLT recipients. However, EBV-specific T-cell immunocompetence, which may be crucial for the long-term control of EBV-mediated proliferation, did not improve.

Antibodies, Monoclonal↗
PubMed2005

Quantitative EBV viral loads and immunosuppression alterations can decrease PTLD incidence in pediatric liver transplant recipients.

Epstein-Barr virus (EBV) is a common viral infection in pediatric liver transplant patients and can lead to development of post-transplant lymphoproliferative disorder (PTLD). Differing studies have used immunosuppression reduction, antiviral medications or i.v. CMV-immunogloublin for EBV prevention and treatment. The purpose of this study was to determine whether implementation of a protocol for frequent EBV monitoring and EBV viral load-driven immunosuppression reduction could decrease the incidence of PTLD in our patient population. All data were prospectively collected between 2001 and 2004 at a single institution. Seventy-three patients were entered into the study. Patients were divided into a historical control group (pre-2001, 30 patients) and a treatment group (post-2001, 43 patients). Approximately 1271 blood samples of 73 patients were collected between 2001 and 2004. Eleven out of 43 patients received immunosuppression tapering due to high EBV viral loads (>4000 copies/microg DNA). One patient developed allograft rejection after immunosuppression modulation. Prior to 2001, the incidence of PTLD at our institution was 16%. After instituting a protocol for EBV monitoring, the incidence of PTLD decreased to 2% (p-value<0.05). These findings illustrate that frequent EBV viral load monitoring and preemptive immunosuppression modulation have an integral role in preventing PTLD in the pediatric liver transplant population.

Adolescent↗