An important obstacle to a functional cure for HIV/AIDS is the persistence of viral reservoirs found throughout the body in various cells and tissues. Reservoirs can be latently infected cells, or in the case of follicular dendritic cells (FDC), non-infected cells that trap infectious virus on their surface through immune complexes (HIV-IC). Although several strategies have been employed to target and eliminate viral reservoirs, they are short-lived and ineffective. In an attempt to provide a long-term approach, chimeric antigen receptor T (CAR-T) cells were designed to eliminate native HIV on FDCs. Although effective at eliminating HIV-infected cells, and halting spreading infection, their ability to eliminate the viral reservoir found on (FDCs) remains unclear. We used a novel second-generation CAR-T cell expressing domains 1 and 2 of CD4 followed by the mannose binding lectin (MBL) to allow recognition of native HIV envelope (Env) to determine the capacity to respond to the viral reservoir found on FDCs. We employed a novel fluorescent lysis assay, the Carboxyfluorescein succinimidyl ester (CFSE) release assay, as well as flow cytometric based assays to detect functional CAR-T activation through IFN-γ production and CD107a (i.e., LAMP1) membrane accumulation to test cytolytic capacity and functional activation of CD4-MBL CAR-T cells, respectively. We demonstrated their efficacy at eliminating HIV-infected cells or cells expressing gp160. However, these CAR-T cells were unable to lyse cells bearing surface bound HIV-IC. We found that failed lysis was not a unique feature of a resistant target, but a limitation in the CAR-T recognition elements. CAR-T cells were inactive in the presence of free HIV or in the presence of concentrated, immobilized virus. Further experiments determined that in addition to gp120 recognition by the CAR-T, the adhesion molecule ICAM-1 was necessary for efficient CAR-T cell killing of HIV-infected cells. CAR-T cell activity and killing were inhibited in the presence of ICAM-1 blocking antibody. These results suggest that other factors, such as adhesion molecules, play a vital role in CAR-T responses to HIV-infected cells. In addition, our findings highlighted the necessity to consider all models of HIV reservoirs, including FDCs, when evaluating therapeutic efficacy.

Novel therapeutic approaches against ovarian cancer (OC) are urgently needed because of its high rate of recurrence even after extensive surgery and multi-agent chemotherapy. We aimed to develop a novel anti-CD24 chimeric antigen receptor (CAR) as an immunotherapeutic approach against OC cells and cancer stem cells (CSC). CSC represents a subpopulation of the tumor characterized by enhanced chemoresistance as well as the increased capability of self-renewal and metastasis. We designed a codon-optimized third-generation CAR containing the highly active single chain variable fragment (scFv) “SWA11” against CD24. We equipped the human NK-cell line NK-92 with the anti-CD24 CAR and an anti-CD19 control CAR using lentiviral transduction. Engineered NK-92 cells showed high cytotoxic activity against CD24-positive OC cell lines (SKOV3, OVCAR3). This effect was restricted to CD24-expressing cells as shown after lentiviral transduction of CD24-negative cell lines (A2780, HEK-293T) with CD24 transmembrane proteins. Additionally, NK-92 cells equipped with our novel anti-CD24 CAR were highly effective against patient-derived primary ovarian cancer cells. The activation of NK cells was shown by specific IFN secretion upon antigen stimulation. To further reduce possible off-target effects in vivo, we applied a dual-CAR approach using an anti-CD24-CD28-41BB fusion protein linked via a 2A sequence to an anti-mesothelin-CD3-CAR. The dual-CAR was simultaneously active against CD24 and mesothelin expressing cells. Our novel anti-CD24-CAR showed a highly cytotoxic effect against OC cell lines and primary OC cells and will be evaluated in future in vivo trials as a promising immunotherapeutic approach against OC.

Glioblastoma (GBM) remains the most aggressive and prevalent malignant primary brain tumor in adults. Unchanged since 2005, standard of care (SoC) consists of surgical resection, followed by radiation therapy (RT) with concurrent and adjuvant chemotherapy with temozolomide (TMZ). Despite these therapeutic efforts, patients succumb to recurrent disease with a median overall survival of 14.6 months and a five-year survival rate of 5.5-6.8%. Therapeutic failure is largely explained by ITH and the presence of treatment-resistant GBM stem-like cells (GSCs). Given the lack of understanding of recurrent GBM and absence of second line therapies patients, I hypothesize that genome-scale functional genetic interrogation will unravel recurrent GBM-specific tumor biology and inform development of novel therapeutics. First, I compared primary and recurrent GBM at the genetic, transcriptomic, proteomic and functional genetic levels. These analyses map a multilayered genetic response to drive tumor recurrence, identifying protein tyrosine phosphatase 4A2 (PTP4A2) as a novel modulator of self-renewal, proliferation and tumorigenicity at GBM recurrence. Mechanistically, genetic perturbation and a small molecule inhibitor of PTP4A2 repress axon guidance activity through a dephosphorylation axis with roundabout guidance receptor 1 (ROBO1) and exploit a genetic dependency on ROBO signaling. Importantly, engineered anti-ROBO1 single-domain antibodies also mimic the effects of PTP4A2 inhibition. Given the genetic dependency on ROBO signaling and enrichment of ROBO1 expression in GBM tissues, I undertook a campaign to evaluate ROBO1 as a therapeutic target in recurrent GBM and develop anti-ROBO1 chimeric antigen receptor T (CAR-T) cells using camelid single-domain antibodies targeting human ROBO1. I optimized the design of anti-ROBO1 CAR-T cells and tested the anti-tumor activity of these modalities in in vitro using patient-derived recurrent GBM lines and orthotopic patient-derived xenograft models. I present data to expand the repertoire of GBM-enriched antigens suitable for effective CAR-T cell therapy. Given that resistance to SoC and disease relapse are inevitable for GBM patients, pre-clinical and clinical advancement of immunotherapeutic modalities, combined with recent insights into the tumor immune microenvironment, are poised to improve clinical outcomes for this patient population. / Thesis / Doctor of Philosophy (PhD) / Glioblastoma remains the most lethal and prevalent primary brain tumor in adults. Standard of care for patients remains unchanged since 2005, consisting of surgery to remove visible tumor at diagnosis (primary tumor), followed by radiation therapy and chemotherapy to treat remaining tumor cells. Despite these therapeutic efforts, tumor relapse (recurrent tumor) is inevitable with no standardized second-line therapy. Patients succumb to recurrent disease with a median overall survival of 14.6 months and only 5.5-6.8% of patients survive five years post diagnosis. Therapy failure and tumor relapse are explained by immense diversity among tumor cells at the DNA and protein levels, giving rise to a subset of tumor cells with abilities to resist therapy and seed the recurrent tumor. Previous studies have presented evolution of tumor cells through therapy, with recurrent tumor cells harboring novel changes at the DNA and protein levels. However, the impact of these changes on tumor cell function has not been evaluated. In this thesis, we developed and applied a genetic screening technique to determine the functional role of thousands of genes in primary and recurrent tumor cells from the same patient. This analysis revealed numerous genes that exhibit differential effects on survival of primary and recurrent tumor cells, including genes that drive recurrent tumor cell growth but are dispensable in primary tumor cells. Functional remodeling of these genes and pathways revealed a new functional role of multiple proteins belonging to a process called axonal guidance in recurrent tumor cells. To evaluate the therapeutic potential of these findings, we deeply interrogated the mechanism by which axonal guidance drives recurrent tumor cells and targeted crucial molecular players using chemical and immunological therapies. Using models that predict clinical effectiveness, we engineered and tested a novel therapy that redirects immune cells to target recurrent tumor cells driven by dysfunctional axonal guidance activity. The goal of this thesis was to discover the functional differences between primary and recurrent tumor cells, thereby leveraging this information to engineer candidate therapies for treatment of recurrent glioblastoma.

T lymphocytes engineered with chimeric antigen receptors (CARs) have shown remarkable success in the treatment of leukemias. Conventional CARs seek to recapitulate TCR and costimulatory signals through fusion of T cell signaling elements into a single receptor. The robust anti-tumor activity of CAR T cells is often accompanied by debilitating toxicities due to excessive T cell activation and cytokine production following infusion. Our lab has generated a novel chimeric receptor termed T cell antigen coupler (TAC), which is designed to engage native T cell signaling domains for cellular activation. In a murine xenograft model, we previously found that TAC T cells mediated rapid tumour regression in the absence of toxicities. Comparatively, CAR T cells elicited significant lethal toxicities to the mice due to reactivity against an unspecific antigen that resulted in excessive proliferation and cytokine production in vivo. Here, we report that TAC and CAR T cells have fundamentally different biology, both at rest, and during activation. TAC T cells were more sensitive to the context of stimulation compared to CAR T cells. Whereas TAC T cells can discriminate between antigen bound to a bead, or antigen present on a cell, CAR T cells do not make the same distinction and responds equally well to both. Compared to several different CAR constructs, TAC T cells are less prone to tonic signaling and T cell differentiation in the absence of antigen. These findings support that TAC T cells may pose a safety benefit as a cancer immunotherapy, due to its distinct biology from CAR T cells that enables them to require more stringent contexts for activation. / Thesis / Master of Science (MSc) / Cytotoxic T cells are also known as “resident killer” cells of the immune system, as they can seek and eliminate diseased or infected tissue, including cancer cells. However, cancer cells can evade elimination by T cells over time. Genetic engineering of T cells allows us to re-arm T cells against cancer cells. T cells isolated from a patient are genetically modified to recognize cancer cells specifically. So far, these modified T cells have been successful against several leukemias. However, the side effects of this treatment can be substantial and life-threatening, due to the massive reaction of the T cells against the cancer cells following infusion. We explore the biology of two different types of engineered T cells to better understand the interaction between T cell and tumour cell. Our results aim towards mitigating the side effects of T cell treatment, while investigating how we can improve its effectiveness for the future.

Tesis por compendio / [EN] Plant viruses are obligate intracellular parasites which were used to develop recombinant plant virus vectors to express heterologous proteins and to modify endogenous metabolic pathways of natural products in plants. The main limitation of many plant virus-based systems is the difficulty to co-express various heterologous proteins in the same cell with proper subcellular localization, which is a crucial question in metabolic engineering. This work provides a solution to overcome this problem by using a potyvirus-based vector system. Potyviruses (genus Potyvirus, family Potyviridae) are plus-strand single-stranded RNA viruses, which have a genome expression strategy that allows the equimolar production of most viral proteins. On the basis of an infectious clone of Tobacco etch virus (TEV), Bedoya et al. (2010) developed an expression system in which the RNA-dependent RNA polymerase (NIb) gene was replaced by an expression cassette, harboring several heterologous proteins. This viral vector was able to express three fluorescent proteins with nucleocytoplasmic localization in equimolar amounts in transgenic tobacco plants in which NIb was supplemented in trans. Despite of the apparent simplicity of potyvirus genome expression strategy, foreign cDNA insertion is a complicated task. Thus, our first goal was to analyze the effect of gene insertion on TEV genome stability. As a result of this work, a novel insertion position was discovered at the amino-terminal end of the potyvirus polyprotein, which opened the possibility to explore new questions of recombinant protein expression. Since metabolic pathways are highly compartmentalized, proper subcellular targeting of enzymes is an essential task. Thus, our second objective centralized on the subcellular targeting of expressed proteins from the TEV-based viral vector. cDNAs coding for the green fluorescent protein (GFP) fused to chloroplast, nucleus and mitochondria targeting signal sequences were inserted into the newly described amino-terminal insertion position or into an internal site, replacing the NIb cistron. Our results showed that for protein delivery to chloroplasts and mitochondria, foreign genes have to be inserted at the amino-terminal site of the viral vector, but for nuclear delivery, both insertion positions are suitable. The last objective of this work was to investigate whether the potyvirus-based vector was able to express an entire heterologous multistep biosynthetic pathway in plant cells. For this aim we purposed to produce lycopene, a plant pigment with health promoting properties. To do so, we inserted cDNAs coding for the enzymes of a three-step metabolic pathway of bacterial origin into the potyvirus-based vector. Infected tobacco plants developed orange symptoms indicating lycopene accumulation, which was confirmed by high-performance liquid chromatography analysis and microscopy observations. Our results also illustrated that the sole expression of Pantoea ananatis phytoene synthase, crtB, is enough to induce carotenoid accumulation, conferring yellow coloration to the infected tissue and serves as reporter system to visually track viral infection in several plant species. / [ES] Los virus de plantas son parásitos intracelulares obligados que han sido utilizados para desarrollar vectores virales y expresar proteínas heterólogas y modificar rutas metabólicas endógenas de productos naturales. La principal limitación de muchos sistemas basados en virus de plantas es la dificultad de coexpresar diversas proteínas heterólogas en la misma célula con la localización subcelular apropiada, lo cual es una cuestión crucial en ingeniería metabólica. Este trabajo presenta una solución para superar este problema mediante el uso de un vector viral basado en un potyvirus. Los potyvirus (género Potyvirus, familia Potyviridae) son virus de RNA de cadena positiva simple que tienen una estrategia de expresión génica que permite la producción de la mayoría de las proteínas virales en cantidades equimolares. Basado en un clon infeccioso del virus del grabado del tabaco (Tobacco etch virus, TEV) Bedoya et al. (2010) desarrollaron un sistema de expresión en el que el gen de la RNA polimerasa dependiente de RNA (NIb) fue sustituido por un casete de expresión, que albergaba varias proteínas heterólogas. Este vector viral fue capaz de expresar tres proteínas fluorescentes con localización nucleocitoplásmica en cantidades equimolares en plantas de tabaco transgénicas que complementaban el cistron NIb en trans. A pesar de la aparente simplicidad de la estrategia de expresión génica de los potyvirus, la inserción de un cDNA foráneo es una tarea complicada. Por lo tanto, nuestro primer objetivo fue analizar el efecto de la inserción en la estabilidad del genoma de TEV. Como resultado de este trabajo, descubrimos una nueva posición de inserción en el extremo amino-terminal de la poliproteína viral que nos permitió explorar otras cuestiones sobre la expresión de proteínas recombinantes. Dado que las vías metabólicas son muy compartimentalizadas, la adecuada localización subcelular de enzimas es una tarea esencial en ingeniería metabólica. Por eso, nuestro segundo objetivo se centró en la distribución de las proteínas heterológas expresadas con el vector viral a diferentes orgánulos subcelulares. cDNAs que codificaban la proteína fluorescente verde (green fluorescent protein, GFP) fusionada a péptidos señal se insertaron en la nueva posición amino-terminal y en un sitio interno, sustituyendo el cistrón NIb, para enviarla al cloroplasto, núcleo y a la mitocondria. Nuestros resultados mostraron que para la distribución de proteínas al cloroplasto y mitocondria, los genes foráneos deben ser insertados en el sitio amino-terminal del vector viral, pero para la distribución nuclear, ambas posiciones son adecuadas. El último objetivo de este trabajo fue estudiar si el vector viral basado en potyvirus es capaz de expresar una ruta biosíntética de múltiples pasos en células vegetales. Para ello nos propusimos producir licopeno, un pigmento vegetal con propiedades beneficiosas para la salud humana. Para ello, insertamos un cDNA que codificaba las enzimas de una ruta metabólica de tres pasos de origen bacteriano en el vector viral. Las plantas de tabaco infectadas con el vector viral desarrollaron síntomas de color naranja indicando la acumulación de licopeno, que fue confirmado por análisis de cromatografía líquida de alta eficacia y observaciones de microscopía. Nuestros resultados también ilustraron que la sola expresión de la fitoeno sintasa de Pantonea ananatis, crtB, es suficiente para inducir la acumulación de carotenoides que confieren una coloración amarilla al tejido infectado y sirve como sistema reportero visual en varias especies de plantas. / [CA] Els virus de plantes són paràsits intracel·lulars obligats que han estat utilitzats per a desenvolupar vectors virals i expressar proteïnes heteròlogues y modificar rutes metabòliques endògenes de productes naturals silenciant certs gens o expressant factors de transcripció i enzims metabòlics. La principal limitació de molts sistemes basats en virus de plantes és la dificultat de coexpressar diverses proteïnes heteròlogues en la mateixa cèl·lula amb la localització subcel·lular apropiada, cosa que és una qüestió crucial en enginyeria metabòlica. Aquest treball presenta una solució per a superar aquest problema mitjançant l'ús d'un vector viral basat en un potyvirus. Els potyvirus (gènere Potyvirus, família Potyviridae) són virus d'RNA de cadena positiva simple que tenen una estratègia d'expressió gènica que permet la producció de la majoria de les proteïnes virals en quantitats equimolars. Basat en un clon infecciós del virus del gravat del tabac (Tobacco etch virus, TEV) Bedoya et al. (2010) van desenvolupar un sistema d'expressió en el qual el gen de l'RNA polimerasa depenent d'RNA (NIb) va ser substituït per un casset d'expressió, que albergava diverses proteïnes heteròlogues. Aquest vector viral va ser capaç d'expressar tres proteïnes fluorescents amb localització nucleocitoplàsmica en quantitats equimolars en plantes de tabac transgèniques que complementaven el cistró NIb en trans. Malgrat l'aparent simplicitat de l'estratègia d'expressió gènica dels potyvirus, la inserció d'un cDNA forà és una tasca complicada. Per tant, el nostre primer objectiu va ser analitzar l'efecte de la inserció en l'estabilitat del genoma de TEV. Com a resultat d'aquest treball, hem descobert una nova posició d'inserció en l'extrem amino terminal de la poliproteïna viral que ens va permetre explorar altres qüestions sobre l'expressió de proteïnes recombinants. Atès que les vies metabòliques són molt compartimentalitzades, l'adequada localització subcel·lular d'enzims és una tasca essencial en enginyeria metabòlica. Per açò, el nostre segon objectiu es va centrar en la distribució de les proteïnes heteròlogues expressades amb el vector viral a diferents orgànuls subcelul·lars. cDNAs que codificaven la proteïna fluorescent verda (green fluorescent protein, GFP) fusionada a pèptids senyal es van inserir en la nova posició amino terminal i en un lloc intern, substituint el cistró NIb, per a enviar-la al cloroplast, nucli i al mitocondri. Els nostres resultats van mostrar que per a la distribució de proteïnes al cloroplast i mitocondri, els gens forans han de ser inserits en el lloc amino terminal del vector viral, però per a la distribució nuclear, ambdues posicions són adequades. El lloc amino terminal va resultar ser més adequat per a produir quantitats més grans de proteïnes recombinants, però el lloc d'inserció intern va demostrar ser més estable. Sobre la base d'aquests resultats, hem sigut capaços de distribuir dues proteïnes fluorescents diferents als cloroplasts i nuclis des d'un únic vector viral. L'últim objectiu d'aquest treball va ser estudiar si el vector viral basat en potyvirus és capaç d'expressar una ruta biosintètica de múltiples passos en cèl·lules vegetals. Per açò ens vam proposar produir licopè, un pigment vegetal amb propietats beneficioses per a la salut humana. Per això inserírem un cDNA que codificaba els tres enzims de una ruta metabòlica de tres passos d'origen bacterià en el vector viral. Les plantes de tabac infectades amb el vector viral van desenvolupar símptomes de color taronja indicant l'acumulació de licopè, que va ser confirmat per anàlisi de cromatografia líquida d'alta eficàcia i observacions de microscòpia. Els nostres resultats també van il·lustrar que la sola expressió de fitoè sintasa de Pantonea ananatis, crtB, és suficient per a induir l'acumulació de carotenoides que confereixen una colora / Majer, E. (2016). Metabolic engineering of plants using a disarmed potyvirus vector [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68477 / Compendio

T lymphocytes are a key aspect of the adaptive immune system, allowing the body to mount effective and long-lasting immune responses. Generally, there are two major types of T cells: CD8+ T cells, which are cytotoxic, and CD4+ T cells, which have many subsets but a majority are “helper” T cells which secrete cytokines to bolster the immune response. For T cells to function appropriately and efficiently, many signaling cascades are activated and inhibited to modulate a T-cell’s function and differentiation. These signals can come from strength and duration of T cell receptor binding, cell-cell interactions with antigen presenting cells and surrounding tissue, as well as from the present cytokine milieu. These signals are dynamic, complex, and can affect many different downstream pathways, making a holistic systems-biology approach the ideal strategy to study signaling in T cells. T-cell activation is normally short (1-3 days), however in some contexts such as cancer or infection, T-cell activation can be chronic (days to weeks) and lead to dysfunction, known as T-cell exhaustion. T-cell exhaustion is a clinically important cell state whereby T cells lose their effector functions (cytotoxicity and secretion of cytokines), proliferative ability, and upregulate many coinhibitory receptors (e.g., PD-1, TIM-3, LAG-3). T-cell exhaustion has been well studied, with some transcriptional drivers (e.g., TOX) and changes in metabolism (e.g., mitochondrial dysfunction) already identified. However, much of what has been discovered about T-cell exhaustion has been done in CD8+ T cells due to their direct role in antigen removal via cytotoxicity. CD4+ T cells are shown to also become exhausted and play an equally important role in the immune response for proper and complete neutralization of the pathogen, and many aspects of CD4+ T-cell exhaustion remain unclear. Here, I report on my quantitative global proteomic and phosphoproteomic studies of T-cell activation in human primary T cells, ranging from healthy acute physiological responses (i.e., hours to days) to dysfunctional long term chronic activation (i.e., days to weeks). I developed an in vitro model of CD4+ T-cell exhaustion and analyzed these cells using a multi-omic approach and uncovered pathways and proteins underlying the progression and demarcation of this understudied cell type. I identified novel CD4+ T-cell exhaustion-associated cell surface markers (e.g., CD276 and FLT-1), transcription factors (e.g., ZEB2), and implicated p300 as playing a role in epigenetic regulation of key exhaustion-associated genes. In addition, I investigated artificial activation signaling in a chimeric antigen receptor (CAR) expressing T-cell model, allowing us to tease apart differences in signaling to better fine tune this potent clinical tool. We compared the basal states of three different CARs and found that changing just one signaling domain can lead to drastic changes in T cells even before introduction of antigen. The resulting systems-level understanding of signaling mechanisms in T cells provides a valuable resource for the advancement of fundamental T-cell biology, for reprogramming T-cell signaling for desired output, and for developing immunotherapies to modulate immune signaling for clinical utility. / 2025-10-29T00:00:00Z

Porcine circovirus type 2 is a single stranded DNA virus that belongs to the genus Circovirus in the family Circoviridae. This virus is associated with many kinds of diseases in pigs and causes significant economic losses in swine-breeding. In this study, two approaches of vaccination were tested in order to develop an effective vaccine against PCV2. The first approach was to test DNA vaccines. For this purpose, eukaryotic expression plasmids encoding two form of PCV2 Cap protein were constructed. The expression plasmids encoding murine TNF-α and IFN-α1 were also prepared for co-immunization with antigen encoding plasmid to enhance the immune response. The second approach is based on the previous finding that chimeric pentamers of VP1 mouse polyomavirus capsid protein fused with PCV2 can induce protective immunity against PCV2. These chimeric pentamers were further modified by AA substitutions in PCV2 Cap immunodominant epitope in order to enhance protective antibody response directed against PCV2. The chimeric pentamers and DNA vaccines were tested for ability to induce antibody immune response against PCV2 in mice. The results showed that chimeric pentamers are more potent inducers of protective antibody immune response against PCV2 compared to DNA vaccines. However, the protective antibody...

Gene-fusions are a prevalent class of genetic variants that are often employed as cancer biomarkers and therapeutic targets. In recent years, high-throughput sequencing of the cellular genome and transcriptome have emerged as a promising approach for the investigation of gene-fusions at the DNA and RNA level. Although, large volumes of sequencing data and complexity of gene-fusion structures presents unique computational challenges. This dissertation describes research that first addresses the bioinformatics challenges associated with the analysis of the massive volumes of sequencing data by developing bioinformatics pipeline and more applied integrated computational workflows. Application of high-throughput sequencing and the proposed bioinformatics approaches for the breast and ovarian cancer study reveals unexpected complex structures of gene-fusions and their functional significance in the onset and progression of cancer. Integrative analysis of gene-fusions at DNA and RNA level shows the key importance of the regulation of gene-fusion at the transcription level in cancer.

Immunotherapy for cancer is a young research field progressing at high speed. The first chimera of an antibody and a signaling chain was designed by Zelig Eshhar and was later further developed to enhance existing T cell therapy by combining a single-chain fragment of an antibody with the CD3 zeta chain of the TCR complex. T cells expressing these chimeric antigen receptors (CARs) could recognize and specifically kill tumor cells. However the T cells, lacked in persistence and tumor rejection did not occur. Thus, the CAR constructs have been improved by providing the T cell with costimulatory signals promoting activation. The focus of this thesis has been to evaluate second and third generation αCD19-CAR T cells for the treatment of B cell leukemia and lymphoma. B cell tumors commonly upregulate anti-apoptotic proteins such as Bcl-2, which generates therapy resistance. In the first paper a second generation (2G) αCD19-CD28-CAR T cell was combined with the Bcl-2 family inhibitor ABT-737. ABT-737 sensitized tumor cells to CAR T cell therapy and may be an interesting clinical combination treatment. In paper II, the phenotype and function of a third generation (3G) αCD19-CD28-4-1BB-CAR T cell were evaluated. B cell-stimulated CAR T cells showed increased proliferation and an antigen-driven accumulation of CAR+ T cells. 3G CAR T cells had equal cytotoxic capacity, similar lineage, memory and exhaustion profile phenotype compared to 2G CARs. However, 3G CAR T cells proliferated better and had increased activation of intracellular signaling pathways compared to 2G CAR T cells. In paper III, αCD19-CD28-4-1BB-CAR T cells were used to stimulate immature dendritic cells leading to an upregulation of maturation markers on co-cultured dendritic cells. Hence, CAR T cells may not only directly kill the tumor cells, but may induce bystander immunity that indirectly aids tumor control. This thesis also include supplementary information about the development and implementation of protocols for GMP production of CAR T cell batches for a phase I/IIa clinical trial currently ongoing for patients with refractory B cell leukemia and lymphoma. So far, two patients have safely been treated on the lowest dose.

In this PhD thesis the potential of T-cells as therapy for disease are explored. The applications of genetically modified T-cells for treatment of cancer and autoimmune disease; the functionality and optimal activation of T-cells are discussed. Successful treatment of cancer with T-cell receptor (TCR)-modified T-cells was first reported in 2006, and is based on recognition of a specific peptide by the TCR in the context of the MHC molecule. As antigen presentation in tumors is often defective and to avoid MHC-restriction, chimeric antigen receptors (CAR) molecules containing an antibody part for recognition of cell surface antigens and TCR and co-receptor signaling domains have been developed. Activated T-cells mount an efficient immune response resulting in the killing of the cancer cell and initiating T-cell proliferation. The rationale for using genetically modified T-cells instead of isolating tumor infiltrating lymphocytes from the tumor and expanding them (TIL therapy) is that it is often very difficult to obtain viable lymphocytes that are able to expand enough in order to use them for therapy. This thesis explores the possibility of using prostate-specific antigens to target T-cells towards prostate cancer. The prostate has many unique tissue antigens but most patients with metastatic prostate cancer have undergone prostatectomy and consequently have “prostate antigen” expression only in cancer cells. We targeted the prostate antigens TARP and PSCA with a HLA-A2 restricted TCR and a CAR respectively. In both cases the tumor-specific T-cells were able to generate potent proliferative and cytotoxic responses in vitro. The PSCA CAR-modified T-cells delayed subcutaneous tumor growth in vivo. It is evident from our in vivo experiments that the PSCA CAR T-cells were unable to completely cure the mice. Therefore, we aimed to improve the quality of the transferred T-cells and their resistance to the immunosuppressive tumor microenvironment. Stimulation with allogeneic lymphocyte-licensed DCs improved the resistance to oxidative stress and antitumor activity of the T-cells. We further investigated the potential of genetically modified regulatory T-cells (Tregs) to suppress effector cells in an antigen-specific manner. Using a strong TCR we hypothesize that the phenotype of the TCR-transduced Tregs may be affected by antigen activation of those cells. We found that the engineered Tregs produced cytokines consistent with Th1, Th2 and Treg phenotypes.