AIM™ platform: A new immunotherapy approach for viral diseases

In addition to complications of acute diseases, chronic viral infections are linked to both malignancies and autoimmune disorders. Lack of adequate treatment options for Epstein-Barr virus (EBV), Human T-lymphotropic virus type 1 (HTLV-1), and human papillomavirus (HPV) remains. The NexImmune Artificial Immune Modulation (AIM) nanoparticle platform can be used to direct T cell responses by mimicking the dendritic cell function. In one application, AIM nanoparticles are used ex vivo to enrich and expand (E+E) rare populations of multi-antigen-specific CD8⁺ T cells for use of these cells as an AIM adoptive cell therapy. This study has demonstrated using E+E CD8⁺ T cells, the functional relevance of targeting EBV, HTLV-1, and HPV. Expanded T cells consist primarily of effector memory, central memory, and self-renewing stem-like memory T cells directed at selected viral antigen peptides presented by the AIM nanoparticle. T cells expanded against either EBV- or HPV-antigens were highly polyfunctional and displayed substantial in vitro cytotoxic activity against cell lines expressing the respective antigens. Our initial work was in the context of exploring T cells expanded from healthy donors and restricted to human leukocyte antigen (HLA)-A*02:01 serotype. AIM Adoptive Cell Therapies (ACT) are also being developed for other HLA class I serotypes. AIM adoptive cell therapies of autologous or allogeneic T cells specific to antigens associated with acute myeloid leukemia and multiple myeloma are currently in the clinic. The utility and flexibility of the AIM nanoparticle platform will be expanded as we advance the second application, an AIM injectable off-the-shelf nanoparticle, which targets multiple antigen-specific T cell populations to either activate, tolerize, or destroy these targeted CD8⁺ T cells directly in vivo, leaving non-target cells alone. The AIM injectable platform offers the potential to develop new multi-antigen specific therapies for treating infectious diseases, cancer, and autoimmune diseases.

97 High throughput screening of HPV-antigen peptides and expansion of tumor-specific T cells for adoptive cell therapy of HPV-associated malignancies

Background

NexImmune is developing highly differentiated immunotherapies to target, activate and expand tumor antigen-specific T cells using the proprietary Artificial Immune Modulation (AIM™) nanotechnology platform. The AIM nanoparticle (AIM-np) technology functions as synthetic dendritic cells capable of directing a specific T cell-mediated immune response. By mimicking natural T cell biology, NexImmune’s cellular therapy product candidates (AIM ACT) are designed to combine the attributes of cellular precision, potency, and persistence with reduced potential for undesired toxicities. Human papilloma virus (HPV) is responsible for >45,000 cancers yearly in the United States, according to the CDC. From 2013–2017 an estimate 79% of cervical, vulva, penis, vaginal, anus, and oropharyngeal cancers were attributed to HPV and of these about 80% were associated with high-risk HPV types 16 and 18. Although multivalent vaccines against high-risk HPV infections exist, significant clinical challenges remain. A limited vaccination rate means many remain vulnerable and vaccination does not treat pre-existing HPV infections or malignancies.

Methods

Therefore, NexImmune is employing its AIM-np technology to generate an adoptive cell therapy (ACT) using its proprietary enrichment and expansion (E+E) ex vivo process to expand clinically relevant numbers of CD8+ T cells that recognize the HPV16 and HPV18 oncogenic antigens (i.e., E6 and E7) expressed by malignant cells of head and neck, cervical, and anal cancers. Using the Immune Epitope Database and Analysis Resource (IEDB), 44 HLA-A2 restricted peptides were identified as potential immunogenic targets for preclinical screening. Using PBMCs from healthy donor-derived apheresis material, different combinations of these peptides were used in the E+E process to expand HPV-cancer specific CD8+ T cells.

Results

After multiple E+E experiments were concluded, 5 peptides were identified that consistently elicited the strongest T cell responses. Furthermore, these CD8+ T cells were predominantly from the central memory (CD62L+CD45RA-) and effector memory (CD62L-CD45RA-) phenotype (sum total 82.18 ± 8.29 [Mean ± SEM]) suggesting their in vivo functionality and persistence will combine anti-tumor activity with long-term immunologic memory.

Conclusions

A similar E+E screening is being conducted with PBMCs isolated from HPV+ cancer patients. A comparison of the CD8+ T cell responses from healthy donor and cancer patient cells will provide critical preclinical data to support a planned FIH trial for HPV-associated malignancies. The current study demonstrates the ability for high-throughput peptide screening to identify clinically relevant peptide cocktails capable of expanding multi-antigen tumor-specific CD8+ T cell populations within 2 weeks.

202 In vivo and in vitro characterization of AIM ACT, a novel nanoparticle-based technology, expanded MART-1 specific T cells

Background

NexImmune is developing highly differentiated immunotherapies to target, activate and expand tumor antigen-specific T cells using the proprietary Artificial Immune Modulation (AIM™) nanotechnology platform. The AIM nanoparticle (AIM-np) technology functions as synthetic dendritic cells capable of directing a specific T cell-mediated immune response. By mimicking natural T cell biology, NexImmune’s non-genetically engineered cellular therapy product candidates (AIM ACT) are designed to combine the attributes of cellular precision, potency, and persistence with reduced potential for undesired toxicities.

Methods

Here we present an example of AIM ACT expanded MART-1 specific T cells and their phenotypic and functional characterization in vitro and in vivo. Leukopaks from healthy donors were used to produce AIM ACT T cell products with our proprietary AIM ACT enrichment and expansion (E+E) manufacturing process and antigen peptide-loaded AIM-nanoparticles.

Results

The final MART1 T cell products include up to 62.8% (20.8% in average) MART-1-specific CD8+ T cells as determined by MART1 peptide (ELAGIGILTV)-loaded multimer staining. MART1-specific T cells were tested in flow cytometry-based and live cell imaging-based cytotoxicity assays using HLA-A2 positive MART1 peptide-loaded target cells. The AIM ACT-generated T cells showed potent cytotoxicity to MART1 peptide-loaded target cells in vitro, while unloaded control cells were not killed. In over 30 independent AIM ACT E+E clinical scale runs, the expanded T cells consisted of a combined average of 91.7% T stem cell like, central and effector memory T cells, as determined by CD62L, CD45RA and CD95 staining. These phenotypes have been associated with long term in vivo persistence and anti-tumor efficacy. In a human melanoma PDX model, we confirmed that transfusion of AIM ACT T cells resulted in long term survival in vivo and significant reduction of tumor growth with complete tumor clearance in 6 out of 15 animals.

Conclusions

The results demonstrate that AIM ACT MART1 T cells have long term persistence and anti-tumor activity in solid tumors such as melanoma, and that the AIM ACT E+E approach is a reproducible clinical scale manufacturing process for non-genetically engineered antigen-specific T cells. The AIM ACT platform is currently being used for generating T cell products for our current clinical trials, NEXI-001 (NCT04284228) and NEXI-002 (NCT04505813), and our pre-clinical development for HPV-associated malignancies. The findings support initiating Phase I trials of adoptive T cell therapy in solid tumors.

Ethics Approval

The study was approved by the Institutional Animal Care and Use Committee (IACUC).

Preliminary analysis of a phase 1/2 study of NEXI-001 donor-derived multi-antigen-specific CD8+ T-cells for the treatment of relapsed acute myeloid leukemia (AML) after allogeneic hematopoietic cell transplantation (HCT)

2538

Background: Allogeneic HCT is a potentially curative therapy for many patients with AML that relies on a graft-versus-leukemia (GvL) effect. Patients who relapse after allogeneic HCT have a poor prognosis and few treatment options. Donor lymphocyte infusion (DLI) can achieve a GvL effect in some patients, however, efficacy is frequently associated with the development graft-versus-host disease (GVHD). There is a substantial need for treatment approaches that enhance the benefit of GVL while decoupling toxicities associated with GVHD. Methods: We report ongoing results from a first-in-human study (NCT04284228) of a non-genetically engineered, donor-derived adoptive cellular therapy product, NEXI-001, which contains multiple populations of CD8+ T cells that recognize different HLA 02.01-restricted peptides from the WT1, PRAME, and Cyclin A1 antigens. NEXI-001 contains T cell memory subtypes that combine anti-tumor potency with long-term persistence. Results: At the time of this analysis, 7 patients with relapsed AML after allogeneic HCT were enrolled. Five Patients were treated with single infusions of NEXI-001 at three different dose levels: 50, 100 and 200 million. Currently, the median follow-up is 5 months. Significantly, GVHD, cytokine release syndrome, neurotoxicity, or NEXI-001-related adverse events were not observed. NEXI-001 treatment resulted in reductions in red blood cell and platelet transfusions and increased donor chimerism. Decreases in myeloblasts in bone marrow and peripheral blood and reduction in the size of an extramedullary myeloid sarcoma were suggestive of an anti-leukemia effect (Table). Correlative studies indicate that NEXI-001 CD8+ cells undergo a rapid proliferation after infusion and are also associated with a robust hostlymphocyte recovery that occurs as quickly Day 3 after infusion. NEXI-001 infused CD8+T cells are detectable by multimer staining in peripheral blood of patients and proliferate over time. TCR sequencing analyses determined that infused NEXI-001 cells contain T cell clones that were undetectable in the peripheral blood of patients at baseline but were detected in blood and bone marrow and persist over time. Conclusions: NEXI-001 has the potential to enhance GvL effect without the associated toxicities of GVHD, cytokine release syndrome, and neurotoxicity. Due to these encouraging results, the trial will proceed with an evaluation of repeated NEXI-001 dosing Clinical trial information: NCT04284228. [Table: see text]

AIM Platform: A Novel Nano Artificial Antigen-Presenting Cell-Based Clinical System Designed to Consistently Produce Multi-Antigen-Specific T-Cell Products with Potent and Durable Anti-Tumor Properties

Over the last decade, tremendous progress has been made in the field of adoptive cell therapy. The two prevailing modalities include endogenous non-engineered approaches and genetically engineered T-cell approaches. Endogenous non-engineered approaches include dendritic cell-based systems and tumor-infiltrating lymphocytes (TIL) that are used to produce multi-antigen-specific T-cell products. Genetically engineered approaches, such as T-cell receptor engineered cells and chimeric antigen receptor T cells are used to produce single antigen-specific T-cell products. It is noted by the authors that there are alternative methods to sort for antigen-specific T cells such as peptide multimer sorting or cytokine secretion assay-based sorting, both of which are potentially challenging for broad development and commercialization. In this review, we are focusing on a novel nanoparticle technology that generates a non-engineered product from the endogenous T-cell repertoire. The most common approaches for ex vivo activation and expansion of endogenous, non-genetically engineered cell therapy products rely on dendritic cell-based systems or IL-2 expanded TIL. Hurdles remain in developing efficient, consistent, controlled processes; thus, these processes still have limited access to broad patient populations. Here, we describe a novel approach to produce cellular therapies at clinical scale, using proprietary nanoparticles combined with a proprietary manufacturing process to enrich and expand antigen-specific CD8⁺ T-cell products with consistent purity, identity, and composition required for effective and durable anti-tumor response.

[Sophisticated surgical management of distinctive patients with benign prostatic hyperplasia (BPH)]

Herein we describe four clinical scenarios. For the standard patient (prostate volume 30-80 ml, life expectancy >10 years) transurethral resection of the prostate (TURP) remains the standard of care, while endoscopic enucleation is a valuable alternative. Patients with a relevant middle lobe profit most from TURP, endourological enucleation procedures, or laser vaporization. In the case of the absence or a moderate-sized middle lobe and the absence of severe bladder outlet obstruction (BOO), minimally invasive procedures such as Rezūm®, UroLift® or prostate artery embolization (PAE) can be offered. Patients have to be informed that long-term data on this specific indication are lacking. Particularly younger men requiring BPH surgery are interested in preserving ejaculatory function. In the presence of severe BOO, ejaculatory-protective TURP or endoscopic enucleation by preserving the pericollicular region or aquablation are the methods of choice providing an antegrade ejaculation in 60-90% of cases. Rezūm®, AquaBeam®, and UroLift® enable preservation of ejaculation in almost 100%; data on PAE with this respect are more controversial. For patients with a small prostate and significant post void residual, a thorough preoperative work-up, including urodynamics and bladder/detrusor wall thickness measurement, is of great importance. Desobstructive surgery provides satisfactory short- and midterm outcome, yet the long-term outcome is disappointing and remains to be determined in greater detail. The broad spectrum of therapeutic options enables today an individualized minimally invasive or surgical management of BPH considering patient wishes, anatomical factors or urodynamic factors. The time of a "one therapy fits all" strategy is definitely history.

Rapid Expansion of Highly Functional Antigen-Specific T Cells from Patients with Melanoma by Nanoscale Artificial Antigen-Presenting Cells

PURPOSE

Generation of antigen-specific T cells from patients with cancer employs large numbers of peripheral blood cells and/or tumor-infiltrating cells to generate antigen-presenting and effector cells commonly requiring multiple rounds of restimulation ex vivo. We used a novel paramagnetic, nanoparticle-based artificial antigen-presenting cell (nano-aAPC) that combines anti-CD28 costimulatory and human MHC class I molecules that are loaded with antigenic peptides to rapidly expand tumor antigen-specific T cells from patients with melanoma.

EXPERIMENTAL DESIGN

Nano-aAPC-expressing HLA-A*0201 molecules and costimulatory anti-CD28 antibody and HLA-A*0201 molecules loaded with MART-1 or gp100 class I-restricted peptides were used to stimulate CD8 T cells purified from the peripheral blood of treatment-naïve or PD-1 antibody-treated patients with stage IV melanoma. Expanded cells were restimulated with fresh peptide-pulsed nano-aAPC at day 7. Phenotype analysis and functional assays including cytokine release, cytolysis, and measurement of avidity were conducted.

RESULTS

MART-1-specific CD8 T cells rapidly expanded up to 1,000-fold by day 14 after exposure to peptide-pulsed nano-aAPC. Expanded T cells had a predominantly stem cell memory CD45RA⁺/CD62L⁺/CD95⁺ phenotype; expressed ICOS, PD-1, Tim3, and LAG3; and lacked CD28. Cells from patients with melanoma were polyfunctional; highly avid; expressed IL2, IFNγ, and TNFα; and exhibited cytolytic activity against tumor cell lines. They expanded 2- to 3-fold after exposure to PD-1 antibody in vivo, and expressed a highly diverse T-cell receptor V beta repertoire.

CONCLUSIONS

Peptide-pulsed nano-aAPC rapidly expanded polyfunctional antigen-specific CD8 T cells with high avidity, potent lytic function, and a stem cell memory phenotype from patients with melanoma.

[Use of synthetic slings and mesh implants in the treatment of female stress urinary incontinence and prolapse : Statement of the Working Group on Urological Functional Diagnostics and Female Urology of the Academy of the German Society of Urology]

Due to a safety alert issued by the US Food and Drug Administration (FDA) in 2011 for transvaginal mesh implants to treat female prolapse as a result of numerous reports of complications such as infection, chronic pain, dyspareunia, vaginal erosion, shrinkage and erosion into other organs nearly all industrial products have been withdrawn from the market in the meantime. The United Kingdom, Australia, and New Zealand extended warnings and prohibitions even on the implantation of midurethral slings (TVT, TOT). In view of these current international controversies regarding the use of implanted materials for the treatment of stress incontinence and prolapse and the lack of clear guidelines for the use of biomaterials, the opinion of the Working Group on Urological Functional Diagnostics and Female Urology should provide clarity. The Opinion is based on the SCENIHR Report of the "European Commission's Scientific Committee on Emerging and Newly Identified Health Risks", the "Consensus Statement of the European Urology Association and the European Urogynaecological Association on the Use of Implanted Materials for Treating Pelvic Organ Prolapse and Stress Urinary Incontinence" and in compliance with relevant EAU and national guidelines and the opinion of the Association for Urogynaecology and Plastic Pelvic Floor Reconstruction (AGUB eV). In addition, recommendations are given for the future handling of implants of slings and meshes for the treatment of stress incontinence and prolapse from a urologic viewpoint.

Abstract 1423: AIM ACT, a novel nanoparticle-based technology that generates therapeutic numbers of functional tumor-specific CD8+ T cells with T stem cell, central and effector memory phenotype in 14 days

Background:

Efficient ex-vivo generation of functional tumor-specific T cells with an optimal memory phenotype remains a significant hurdle to the broad application of adoptive cell transfer (ACT) protocols for the treatment of cancer. Genetically engineered T cells represent a currently available option, but the genetic manipulation of T cells presents significant challenges in terms of manufacturing, cost and addressing tumor escape mechanisms. Here, we describe a novel nanoparticle-based approach for generating tumor-specific T cells at clinical grade and scale from the endogenous T cell repertoire using artificial antigen presenting cells (aAPC).

Methods:

aAPC consist of a paramagnetic nanoparticle to which humanized HLA-A2-Ig dimer-molecules and anti-CD28 antibodies are covalently linked. aAPC are loaded with multiple HLA-A2 restricted peptides and used to magnetically enrich and expand tumor-specific CD8+ T cells. Using peptide loaded aAPC, a fully enclosed and automated GMP T cell expansion platform has been developed that consistently generates clinically relevant numbers of tumor-specific, T stem cell, central and effector memory CD8+ T cells in 14 days, providing an alternative to genetically manipulated T cells.

Results:

Starting from a healthy donor leukopak, tumor-specific CD8+ T cells were generated using an aAPC cocktail loaded with 5 HLA-A2 epitopes from AML tumor antigens WT1, PRAME and Cyclin A1. On average, 1-2 x109 T cells were generated that were >90% of the memory phenotype that averaged 18% T stem cells, 40% central memory and 35% effector memory CD8+ T cells. AML-specific T cells were expanded 500 to >5000-fold from low frequency precursor populations. The system has also been used to generate MM specific T cells of the same quality from both from fresh leukopacks and cryopreserved PBL. All generated T cells were fully functional, as demonstrated by intra-cellular cytokine analysis and tumor cell killing.

Conclusion:

AIM ACT is a novel nanoparticle-based T cell platform developed for the rapid, streamlined generation of clinically-relevant numbers of tumor-specific, T stem cell, central and effector memory CD8+ T cells from donor PBMC in 14 days. The platform described here will be used to generate multi-antigen specific CD8+ T cell products that will be evaluated in multi-center P1/2 clinical trials. These trials will enroll r/r MM patients and r/r AML patients pre- and post-allogeneic hematopoietic stem cell transplant. The flexibility of the AIM ACT system, as shown has potential for clinical evaluation in other hematological tumors and can be used for targeting neo-epitopes.

Citation Format: Sojung Kim, Lauren Suarez, Emily Lu, Celine Walmacq, Daniel Dembrow, Juan Varela, Dan Bednárik, Kenneth Carter, Naimish Pandya, Kristi Jones, Mathias Oelke. AIM ACT, a novel nanoparticle-based technology that generates therapeutic numbers of functional tumor-specific CD8+ T cells with T stem cell, central and effector memory phenotype in 14 days [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1423.

[Diagnostic procedures and diagnostic strategy for lower urinary tract symptoms/benign prostatic hyperplasia : An overview]

BACKGROUND

Lower urinary tract symptoms due to benign prostatic hyperplasia (LUTS/BPH) is the most common condition affecting the lower urinary tract of men. Evidence-based assessment is the basis for an ideal treatment approach.

OBJECTIVES

To provide an overview of the current status of diagnostic measures for LUTS/BPH.

MATERIALS AND METHODS

Descriptive review of the literature on the diagnosis of LUTS/BPH.

RESULTS

A medical history inquiring about LUTS/BPH symptoms and burden as well as a standardized and validated symptom questionnaire such as the International Prostate Symptom Score (IPSS) are the basis of the assessment. A physical examination including a rectal exam and the ultrasonography of the lower and upper urinary tract are also part of the basic diagnostic workup. Prostate size is ideally measured by transrectal ultrasound. Serum prostate-specific antigen measurement may help to estimate the prostate size and the risk fo progression. It can also be helpful in the detection of prostate cancer. Urine dipstick or sediment is used to exclude urinary tract infection, hematuria, or glucosuria. Voiding dysfunction can be detected by uroflowmetry. In addition to the aforementioned examinations, further tests such as frequency-voiding charts, multichannel urodynamic evaluation, measurement of detrusor wall thickness and X‑ray imaging of the upper urinary tract as well as a cystoscopy may be offered if needed.

CONCLUSIONS

Diagnostics of LUTS/BPH consist of basic exams as well as optional exams and can be used to assess the progression risk, to identify complications and to offer the ideal treatment.

Selective Effects of mTOR Inhibitor Sirolimus on Naïve and CMV-Specific T Cells Extending Its Applicable Range Beyond Immunosuppression

Cytomegalovirus (CMV) infection/reactivation remains among the most important complications of immunosuppression after transplantation. However, recent clinical observations indicate that mammalian target of rapamycin (mTOR) inhibition with sirolimus may improve the outcome of CMV complications. Underlying mechanisms of this observation, particularly the effect of sirolimus on naïve- and CMV-specific cytotoxic CD8⁺ T-cell (CMV-CTL) functionality is still undiscovered. Here, the influence of sirolimus on naïve and memory CMV-CTLs was determined by CD3/CD28 crosslinking and alloreactivity assays. After stimulating CMV-CTL with HLA-A^*02:01-restricted CMVpp65-peptide loaded artificial antigen-presenting cells (aAPCs), we measured the effect of sirolimus on T-cell proliferation, phenotype, and functionality. Sirolimus significantly improved CMV-specific effector memory T-cell function and negatively influenced naïve T cells. This unique mechanism of action was further characterized by increased secretion of interferon-gamma (IFN-γ), granzyme B (GzB) and enhanced target-cell-dependent cytotoxic capacity of activated CMV-CTLs. Next-generation-sequencing (NGS) was applied to monitor T-cell receptor (TCR)-repertoire dynamics and to verify, that the increased functionality was not related to sirolimus-resistant CTL-clones. Instead, modulation of environmental cues during CMV-CTL development via IL-2 receptor (IL-2R)-driven signal transducer and activator of transcription-5 (STAT-5) signaling under mTOR inhibition allowed fine-tuning of T-cell programming for enhanced antiviral response with stable TCR-repertoire dynamics. We show for the first time that sirolimus acts selectively on human naïve and memory T cells and improves CMV-specific T-cell function via modulation of the environmental milieu. The data emphasize the importance to extend immune monitoring including cytokine levels and T-cell functionality which will help to identify patients who may benefit from individually tailored immunosuppression.

Soluble MHC class I complexes for targeted immunotherapy

Major histocompatibility complexes (MHC) have been used for more than two decades in clinical and pre-clinical approaches of tumor immunotherapy. They have been proven efficient for detecting anti-tumor-specific T cells when utilized as soluble multimers, immobilized on cells or artificial structures such as artificial antigen-presenting cells (aAPC) and have been shown to generate effective anti-tumor responses. In this review we summarize the use of soluble MHC class I complexes in tumor vaccination studies, highlighting the different strategies and their contradicting results. In summary, we believe that soluble MHC class I molecules represent an exciting tool with great potential to impact the understanding and development of immunotherapeutic approaches on many levels from monitoring to treatment.

Antigen-specific T cell Redirectors: a nanoparticle based approach for redirecting T cells

Redirection of T cells to target and destroy tumors has become an important clinical tool and major area of research in tumor immunology. Here we present a novel, nanoparticle-based approach to selectively bind antigen-specific cytotoxic T cells (CTL) and redirect them to kill tumors, termed ATR (Antigen-specific T cell Redirectors). ATR were generated by decorating nanoparticles with both an antigen-specific T cell binding moiety, either peptide loaded MHC-Ig dimer or clonotypic anti-TCR antibody, and a model tumor cell binding moiety, anti-CD19 antibody to engage CD19+ tumor cells. ATR stably bind tumor cells and CTL in a dose dependent fashion and stimulate antigen-specific conjugate formation between those cells. ATR induced redirected lysis of tumor cells in vitro, as demonstrated by 51Cr-release killing. In vivo ATR administration led to reduced tumor growth in a SCID/beige human lymphoma treatment model. In summary, ATR represent a novel, nanoparticle based approach for redirecting antigen-specific CTL to kill tumors.

Cord blood-derived T cells allow the generation of a more naïve tumor-reactive cytotoxic T-cell phenotype

BACKGROUND

Transplantation of hematopoietic stem cells (HSCs) from peripheral blood (PB) or cord blood (CB) is well established. HSCs from CB are associated with a lower risk of graft-versus-host disease (GVHD), but antigen-independent expanded CB- and PB-derived T cells can induce GVHD in allo-HSC recipients. CB-derived cells might be more suitable for adoptive immunotherapy as they have unique T-cell characteristics. Here, we describe functional differences between CB and PB T cells stimulated with different cytokine combinations involved in central T-cell activation.

STUDY DESIGN AND METHODS

Isolated CD8+ T cells from CB and PB were stimulated antigen independently with anti-CD3/CD28 stimulator beads or in an antigen-dependent manner with artificial antigen-presenting cells loaded with the HLA-A*02:01-restricted peptide of tumor-associated melanoma antigen recognized by T cells 1 (MART1). CB and PB T cells cultured in the presence of interleukin (IL)-7, IL-15, IL-12, and IL-21 were characterized for T-cell phenotype and specificity, that is, by CD107a, interferon-γ, tumor necrosis factor-α, and IL-2 expression.

RESULTS

After antigen-independent stimulation, activated CD8+ CB T cells exhibited stronger proliferation and function than those from PB. After antigenic stimulation, MART1-reactive CB T cells were naïve (CD45RA+CCR7+), cytotoxic, and highly variable in expressing homing marker CD62L. Addition of IL-21 resulted in increased T-cell proliferation, whereas supplementation with IL-12 decreased IL-21-induced expansion, but increased the functionality and cytotoxicity of CB and PB T cells.

CONCLUSION

MART1-reactive CB T cells with a more naïve phenotype and improved properties for homing can be generated. The results contribute to better understanding the effects on GVHD and graft versus tumor.

Nanoparticle based enrichment and expansion of self and neo-epitope specific CD8+ T cells in murine melanoma

Neo-antigen T cell responses against tumors has created a new avenue to target and kill patients’ tumors while possibly decreasing autoimmune side effects. CD8+ Neo-antigen T cells have the potential benefit to be a source of T cells that are not limited by peripheral tolerance or deleted from the T cell repertoire by central tolerance. To understand the differences between self and neo-antigens T cell responses, the two types of T cell populations must be compared side-by-side by anti-tumor responses and phenotypic differences. Following another group (Castle; 2012) that identified mutated proteins from long sequences in murine melanoma our current work has identified the short peptide epitopes that can stimulate neo-antigen T cell responses. The candidate neo-epitopes were validated by peptide stabilization assays and in vitro T cell stimulations with nanoparticle artificial antigen presenting cells. 11 naïve neo-antigen T cells responses were identified out of a total of 19 possible candidate neo-antigens. Artificial antigen presenting cells were used to assess neo and self-antigen tumor specific responses in the naïve T cell repertoire and after tumor exposure to B16 murine melanoma. After exposure to tumor, neo-epitope T cell responses showed larger fold expansion as compared to a self-antigens expressed by the tumor cells. From this work, we deliver a proof of concept of a streamlined way to screen candidate neo-epitopes and identify rare endogenous T cell populations; and evaluate the benefit of T cell directed immunotherapies on different T cell populations.

[Pharmacological treatment of benign prostatic hyperplasia]

The pharmacological treatment of benign prostatic hyperplasia (BPH) is indicated when men suffer from lower urinary tract symptoms (LUTS) but there are no absolute indications for prostate surgery or severe bladder outlet obstruction. Phytotherapy can be used in men with mild to moderate LUTS and alpha-blockers can quickly and effectively decrease the LUTS and symptomatic disease progression. Phosphodiesterase type 5 inhibitors (PDE5-I) are an alternative to alpha-blockers when men experience bothersome side effects from alpha-blockers or erectile dysfunction. If patients predominantly have bladder storage symptoms and a small prostate, muscarinic receptor antagonists are a viable treatment option. The combination of alpha-blocker plus muscarinic receptor antagonist is more efficacious in reducing LUTS than the single drugs alone. The 5 alpha-reductase inhibitors (5ARI) can significantly decrease LUTS and disease progression (e.g. acute urinary retention and need for prostate surgery) in men with larger prostates (> 30-40 ml). The combination of 5ARI plus alpha-blocker can reduce LUTS and disease progression more effectively than drug monotherapy. Combination therapy with PDE5-I (tadalafil) plus 5ARI (finasteride) reduces LUTS more substantially than 5ARI alone and, additionally, PDE5-Is reduce the sexual side effects during 5ARI treatment.

Granulocyte colony-stimulating factor impairs CD8(+) T cell functionality by interfering with central activation elements

Besides mobilizing stem cells into the periphery, granulocyte colony-stimulating factor (G-CSF) has been shown to influence various types of innate and adaptive immune cells. For example, it impairs the effector function of cytotoxic T lymphocytes (CTLs). It is assumed that this effect is mediated indirectly by monocytes, regulatory T cells and immunomodulatory cytokines influenced by G-CSF. In this study, isolated G-CSF-treated CD8(+) T cells were stimulated antigen-dependently with peptide-major histocompatibility complex (pMHC)-coupled artificial antigen-presenting cells (aAPCs) or stimulated antigen-independently with anti-CD3/CD28 stimulator beads. By measuring the changes in interferon (IFN)-γ and granzyme B expression at the mRNA and protein level, we showed for the first time that G-CSF has a direct effect on CD8(+) CTLs, which was confirmed based on the reduced production of IFN-γ and granzyme B by the cytotoxic T cell line TALL-104 after G-CSF treatment. By investigating further elements affected by G-CSF in CTLs from stem cell donors and untreated controls, we found a decreased phosphorylation of extracellular-regulated kinase (ERK)1/2, lymphocyte-specific protein tyrosine kinase (Lck) and CD3ζ after G-CSF treatment. Additionally, miRNA-155 and activation marker expression levels were reduced. In summary, our results show that G-CSF directly influences the effector function of cytotoxic CD8(+) T cells and affects various elements of T cell activation.

VEGF Potentiates GD3-Mediated Immunosuppression by Human Ovarian Cancer Cells

PURPOSE

Natural killer T (NKT) cells are important mediators of antitumor immune responses. We have previously shown that ovarian cancers shed the ganglioside GD3, which inhibits NKT-cell activation. Ovarian cancers also secrete high levels of VEGF. In this study, we sought to test the hypothesis that VEGF production by ovarian cancers suppresses NKT-cell-mediated antitumor responses.

EXPERIMENTAL DESIGN

To investigate the effects of VEGF on CD1d-mediated NKT-cell activation, a conditioned media model was established, wherein the supernatants from ovarian cancer cell lines (OV-CAR-3 and SK-OV-3) were used to treat CD1d-expressing antigen-presenting cells (APC) and cocultured with NKT hybridomas. Ovarian cancer-associated VEGF was inhibited by treatment with bevacizumab and genistein; conditioned medium was collected, and CD1d-mediated NKT-cell responses were assayed by ELISA.

RESULTS

Ovarian cancer tissue and ascites contain lymphocytic infiltrates, suggesting that immune cells traffic to tumors, but are then inhibited by immunosuppressive molecules within the tumor microenvironment. OV-CAR-3 and SK-OV-3 cell lines produce high levels of VEGF and GD3. Pretreatment of APCs with ascites or conditioned medium from OV-CAR-3 and SK-OV-3 blocked CD1d-mediated NKT-cell activation. Inhibition of VEGF resulted in a concomitant reduction in GD3 levels and restoration of NKT-cell responses.

CONCLUSIONS

We found that VEGF inhibition restores NKT-cell function in an in vitro ovarian cancer model. These studies suggest that the combination of immune modulation with antiangiogenic treatment has therapeutic potential in ovarian cancer. Clin Cancer Res; 22(16); 4249-58. ©2016 AACR.

[Urinary incontinence in men]

Stress urinary incontinence in men is predominantly iatrogenic whereby radical prostatectomy is the most common cause with persistent stress urinary incontinence rates varying between 10 % and 25 %. The first line therapy for postoperative male stress urinary incontinence is physiotherapy, especially pelvic floor muscle rehabilitation. If conservative treatment fails to show sufficient improvement, surgical therapy is recommended. Several treatment options are currently available for the surgical treatment of male stress urinary incontinence including artificial sphincters, adjustable and functional sling systems, bulking agents and implantable balloon systems.

Impact of cardiovascular risk factors and related comorbid conditions and medical therapy reported at baseline on the treatment response to tadalafil 5 mg once-daily in men with lower urinary tract symptoms associated with benign prostatic hyperplasia: an integrated analysis of four randomised, double-blind, placebo-controlled, clinical trials

PURPOSE

The influence of cardiovascular risk factors/comorbidities on response to oral once-daily tadalafil 5 mg was explored in men with lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH).

METHODS

This post hoc analysis pooled data from four double-blind studies in which 1498 men with > 6-mo history of LUTS/BPH were randomised and received either once-daily placebo (n = 746) or tadalafil 5 mg (n = 752) for 12 weeks. Descriptive statistics were reported for changes in total International Prostate Symptom Score (IPSS), IPSS voiding and storage subscores, and IPSS quality-of-life (QoL) index. Treatment group differences by baseline clinical and cardiovascular factors and medical therapies were examined using analysis of covariance.

RESULTS

Tadalafil was effective in men with LUTS/BPH and cardiovascular risk factors/comorbidities except for patients receiving > 1 antihypertensive medication. Placebo-adjusted least squares (LS) mean improvements in total IPSS were -1.2 (95% CI: -2.5 to -0.0) in men taking > 1 antihypertensive medication vs. -3.3 (95% CI: -4.4 to -2.1) in men taking one medication (interaction p = 0.020). In addition, placebo-adjusted LS mean improvements in total IPSS were -0.2 (95% CI, -2.1 to 1.7) in men who reported use of diuretics vs. -2.8 (95% CI, -3.7 to -1.9) in men who reported taking other antihypertensive medications vs. -2.3 (95% CI, -3.2 to -1.5) in men who reported not using any antihypertensive drug (p-value for interaction = 0.053).

CONCLUSIONS

Once-daily tadalafil 5 mg improved LUTS/BPH, regardless of severity, in men with coexisting cardiovascular risk factors/comorbidities, except for patients with history of > 1 drug for arterial hypertension. Use of diuretics may contribute to patients' perception of a negated efficacy of tadalafil on LUTS/BPH. Comorbidities should be considered when choosing the optimal medicine to treat men with LUTS/BPH.

Telomere Length as an Indicator of the Robustness of B- and T-Cell Response to Influenza in Older Adults

BACKGROUND

Telomeres provide a key mechanism for protecting the integrity of chromosomes and their attrition after cell division and during aging are evident in lymphocytes. However, the significance of telomere shortening in age-associated decline of immune function is unknown.

METHODS

We selected 22 HLA-A2-positive healthy older adults who have relatively short or long telomere lengths to compare their antibody response against the influenza vaccine, and their CD8(+) T-cell response against an influenza antigen.

RESULTS

B cells from individuals with a robust antibody response to the influenza vaccine had significantly longer telomeres than those with a poor antibody response. Monocyte-derived antigen-presenting cells of both short and long telomere groups induced similar expansions of influenza M1-specific CD8(+) T cells. Vaccination did not increase M1-specific CD8(+) T cells in blood, but M1-specific CD8(+) T cells from the long telomere group exhibited significantly greater expansion in vitro than those from the short telomere group. Finally, M1-specific CD8(+) T cells that underwent more expansions had significantly longer telomeres than cells with fewer divisions.

CONCLUSIONS

Telomere length is positively associated with a robust lymphocyte response, and telomere attrition may contribute to the age-associated decline of adaptive immunity.

Enrichment and Expansion with Nanoscale Artificial Antigen Presenting Cells for Adoptive Immunotherapy

Adoptive immunotherapy (AIT) can mediate durable regression of cancer, but widespread adoption of AIT is limited by the cost and complexity of generating tumor-specific T cells. Here we develop an Enrichment + Expansion strategy using paramagnetic, nanoscale artificial antigen presenting cells (aAPC) to rapidly expand tumor-specific T cells from rare naïve precursors and predicted neo-epitope responses. Nano-aAPC are capable of enriching rare tumor-specific T cells in a magnetic column and subsequently activating them to induce proliferation. Enrichment + Expansion resulted in greater than 1000-fold expansion of both mouse and human tumor-specific T cells in 1 week, with nano-aAPC based enrichment conferring a proliferation advantage during both in vitro culture and after adoptive transfer in vivo. Robust T cell responses were seen not only for shared tumor antigens, but also for computationally predicted neo-epitopes. Streamlining the rapid generation of large numbers of tumor-specific T cells in a cost-effective fashion through Enrichment + Expansion can be a powerful tool for immunotherapy.

CD47 Enhances In Vivo Functionality of Artificial Antigen-Presenting Cells

PURPOSE

Artificial antigen-presenting cells, aAPC, have successfully been used to stimulate antigen-specific T-cell responses in vitro as well as in vivo. Although aAPC compare favorably with autologous dendritic cells in vitro, their effect in vivo might be diminished through rapid clearance by macrophages. Therefore, to prevent uptake and minimize clearance of aAPC by macrophages, thereby increasing in vivo functionality, we investigated the efficiency of "don't eat me" three-signal aAPC compared with classical two-signal aAPC.

EXPERIMENTAL DESIGN

To generate "don't eat me" aAPC, CD47 was additionally immobilized onto classical aAPC (aAPC(CD47+)). aAPC and aAPC(CD47+) were analyzed in in vitro human primary T-cell and macrophage cocultures. In vivo efficiency was compared in a NOD/SCID T-cell proliferation and a B16-SIY melanoma model.

RESULTS

This study demonstrates that aAPC(CD47+) in coculture with human macrophages show a CD47 concentration-dependent inhibition of phagocytosis, whereas their ability to generate and expand antigen-specific T cells was not affected. Furthermore, aAPC(CD47+)-generated T cells displayed equivalent killing abilities and polyfunctionality when compared with aAPC-generated T cells. In addition, in vivo studies demonstrated an enhanced stimulatory capacity and tumor inhibition of aAPC(CD47+) over normal aAPC in conjunction with diverging biodistribution in different organs.

CONCLUSIONS

Our data for the first time show that aAPC functionalized with CD47 maintain their stimulatory capacity in vitro and demonstrate enhanced in vivo efficiency. Thus, these next-generation aAPC(CD47+) have a unique potential to enhance the application of the aAPC technology for future immunotherapy approaches.

Management of benign prostatic hyperplasia: role of phosphodiesterase-5 inhibitors

Several studies have highlighted a strong association between benign prostatic hyperplasia/lower urinary tract symptoms (BPH/LUTS) and erectile dysfunction (ED), particularly in elderly men. Many epidemiological trials, such as in vitro and in vivo studies, have reported the emerging role of metabolic syndrome, including abdominal obesity, impaired glucose metabolism, hypertriglyceridemia, low high-density lipoprotein cholesterol, and hypertension, in the development and progression of urinary and sexual symptoms. Moreover, many authors have focused their studies on the identification of all the shared pathogenetic mechanisms of LUTS/BPH and ED, including alteration of cyclic guanosine monophosphate and RhoA-ROCK pathways or vascular and neurogenic dysfunction. All these are potential targets for proposed phosphodiesterase type 5 inhibitors (PDE5-Is). Therefore, several trials have recently been designed to evaluate the role of PDE5-Is alone or in combination with conventional treatment for BPH, such as α-adrenergic blockers, in men affected by LUTS/BPH, with or without ED. Different PDE5-Is are in clinical use worldwide and currently six of them are licensed for the oral treatment of ED. All these compounds differ in pharmacokinetic factors, with influence on drug action, and subsequently in the overall safety and efficacy profile.

Adoptive T cell immunotherapy for cancer

Harnessing the immune system to recognize and destroy tumor cells has been the central goal of anti-cancer immunotherapy. In recent years, there has been an increased interest in optimizing this technology in order to make it a clinically feasible treatment. One of the main treatment modalities within cancer immunotherapy has been adoptive T cell therapy (ACT). Using this approach, tumor-specific cytotoxic T cells are infused into cancer patients with the goal of recognizing, targeting, and destroying tumor cells. In the current review, we revisit some of the major successes of ACT, the major hurdles that have been overcome to optimize ACT, the remaining challenges, and future approaches to make ACT widely available.

MHC-Ig induces memory T cell formation in vivo and inhibits tumour growth

Induction of a T cell mediated immune response is critical for the eradication of viral infections and tumours. Soluble peptide-loaded major histocompatibility complex-Ig (^pep−MHC-Ig) have been shown to bind their cognate ligands, T cell receptor, with high affinity, and are successfully used to visualize antigen-specific T cells. Furthermore, immobilized ^pep−MHC-Ig can activate and expand antigen-specific T cells in vitro and in vivo. In this study, we investigate the use of ^pep−MHC-Ig as a potential strategy to modulate antigen specific T cell immune responses in vivo. ^SIY−K^b-Ig immunization, together with the pre-activation by an anti-CD40 monoclonal antibody, is able to stimulate a strong expansion of adoptively transferred 2C transgenic T cells and the formation of long term antigen-specific memory T cells. In addition, mechanistic studies show that the ^pep−MHC-Ig molecules directly activate T cells in vivo without requiring uptake and reprocessing by antigen-presenting cells. Furthermore, B6 mice immunized with ^pep−MHC-Ig molecules inhibit tumour growth in a B16-SIY melanoma prevention model. Thus, soluble ^pep−MHC-Ig molecules represent a powerful tool for active immunotherapy.

Killer artificial antigen presenting cells (KaAPC) for efficient in vitro depletion of human antigen-specific T cells

Current treatment of T cell mediated autoimmune diseases relies mostly on strategies of global immunosuppression, which, in the long term, is accompanied by adverse side effects such as a reduced ability to control infections or malignancies. Therefore, new approaches need to be developed that target only the disease mediating cells and leave the remaining immune system intact. Over the past decade a variety of cell based immunotherapy strategies to modulate T cell mediated immune responses have been developed. Most of these approaches rely on tolerance-inducing antigen presenting cells (APC). However, in addition to being technically difficult and cumbersome, such cell-based approaches are highly sensitive to cytotoxic T cell responses, which limits their therapeutic capacity. Here we present a protocol for the generation of non-cellular killer artificial antigen presenting cells (KaAPC), which allows for the depletion of pathologic T cells while leaving the remaining immune system untouched and functional. KaAPC is an alternative solution to cellular immunotherapy which has potential for treating autoimmune diseases and allograft rejections by regulating undesirable T cell responses in an antigen specific fashion.

Different competency of CMV-pp65 or Flu-M1 specific CD8+ T cells in naïve and central memory population in healthy human adults (TRAN3P.885)

The competency of antigen specific (Ag+) lymphocytes plays a critical role in the outcome of an adaptive immune response during an infection. Although the precursor frequency of Ag+ T cells often serves as an indicator, the evaluation of the proliferative capacity of Ag+ T cells of healthy humans to known viral antigens is limited. Here, we compared CD8 T cell responses to the antigen from cytomegalovirus (CMV-pp65) or influenza virus (Flu-M1) using an artificial antigen presenting system in vitro. We found that CD8 T cell responses (proliferation and Granzyme B production) to these two antigens varied in 23 healthy adults analyzed. The antigen specific CD8 T cell expansion did not correlate with the precursor frequency of total Ag+ CD8 T cells. Further comparing the response of isolated naïve (Tn) and central memory (Tcm) CD8 T cells showed that Tcm expanded more than Tn did to both antigens. Finally, we found that longer telomere lengths in CD8 T cells were positively correlated with the better expansion of these Ag+ CD8 T cells. Together, our study shows that antigen specific CD8 T cell response to CMV-pp65 and Flu-M1 is varied in healthy adults and the capacity of proliferation of these Ag+ CD8 T cells depends partly on the telomere length in these cells.

Induction of polyfunctional human memory T cells by Wnt pathway activation (VAC3P.949)

Polyfunctionality is a hallmark of protective immunity against pathogens and cancer. However, the molecular mechanisms governing the induction of polyfunctional T cells are not completely understood. We found that during antigen-driven expansion of human virus-specific T cells, Wnt pathway activation enhances the CD62L+, CD28+, and KLRG1- central memory T cell phenotype and promoted the generation of highly polyfunctional virus-specific T cells. Such effects are not only seen in influenza-specific responses but also in terminally differentiated CMV- and HIV-specific T cells. Mechanistically induction of polyfunctionality was independent of arresting antigen-specific cell expansion and is T cell-intrinsic. These findings provide the first evidence that Wnt pathway activation leads to polyfunctional antigen-specific memory human T cells responses and therefore have implications for treatment of chronic viral infections and cancer.

Sprouty-2 regulates HIV-specific T cell polyfunctionality

The ability of individual T cells to perform multiple effector functions is crucial for protective immunity against viruses and cancer. This polyfunctionality is frequently lost during chronic infections; however, the molecular mechanisms driving T cell polyfunctionality are poorly understood. We found that human T cells stimulated by a high concentration of antigen lacked polyfunctionality and expressed a transcription profile similar to that of exhausted T cells. One specific pathway implicated by the transcription profile in control of T cell polyfunctionality was the MAPK/ERK pathway. This pathway was altered in response to different antigen concentrations, and polyfunctionality correlated with upregulation of phosphorylated ERK. T cells that were stimulated with a high concentration of antigen upregulated sprouty-2 (SPRY2), a negative regulator of the MAPK/ERK pathway. The clinical relevance of SPRY2 was confirmed by examining SPRY2 expression in HIV-specific T cells, where high levels of SPRY2 were seen in HIV-specific T cells and inhibition of SPRY2 expression enhanced the HIV-specific polyfunctional response independently of the PD-1 pathway. Our findings indicate that increased SPRY2 expression during chronic viral infection reduces T cell polyfunctionality and identify SPRY2 as a potential target for immunotherapy.

Improving the health care of geriatric patients: management of urinary incontinence: a position paper

A multidisciplinary German expert group met in 2012 to discuss the current status and prospects of health care of geriatric patients with urinary incontinence in Germany. The purpose of this position paper is to raise awareness among health care providers for the challenges associated with adequate management of urinary incontinence in frail elderly. The experts agree that a multidisciplinary collaboration is essential for the successful treatment of urinary incontinence symptoms which are often associated with loss of autonomy and social isolation. For most geriatric patients, usually the general practitioner is the first contact when seeking help. Hence, the general practitioner plays a crucial role in the coordination of diagnosis and treatment. The involved health care providers should have adequate education and training in their respective disciplines and should be networked allowing quick turnaround times. Non-pharmacological treatments (e.g. behavioural interventions) should have been tried before any pharmacotherapy is initiated. If pharmacological treatment of urinary incontinence involves the use of anticholinergic agents, cognitive performance should be monitored regularly. If indicated, anticholinergic agents with a documented efficacy and safety profile, explicitly assessed in the elderly population, should be preferred.

Nanoscale artificial antigen presenting cells for T cell immunotherapy

Artificial antigen presenting cells (aAPC), which deliver stimulatory signals to cytotoxic lymphocytes, are a powerful tool for both adoptive and active immunotherapy. Thus far, aAPC have been synthesized by coupling T cell activating proteins such as CD3 or MHC-peptide to micron-sized beads. Nanoscale platforms have different trafficking and biophysical interaction properties and may allow development of new immunotherapeutic strategies. We therefore manufactured aAPC based on two types of nanoscale particle platforms: biocompatible iron-dextran paramagnetic particles (50-100 nm in diameter) and avidin-coated quantum dot nanocrystals (~30 nm). Nanoscale aAPC induced antigen-specific T cell proliferation from mouse splenocytes and human peripheral blood T cells. When injected in vivo, both iron-dextran particles and quantum dot nanocrystals enhanced tumor rejection in a subcutaneous mouse melanoma model. This is the first description of nanoscale aAPC that induce antigen-specific T cell proliferation in vitro and lead to effective T cell stimulation and inhibition of tumor growth in vivo.

FROM THE CLINICAL EDITOR

Artifical antigen presenting cells could revolutionize the field of cancer-directed immunotherapy. This team of investigators have manufactured two types of nanoscale particle platform-based aAPCs and demonstrates that both iron-dextran particles and quantum dot nanocrystals enhance tumor rejection in a melanoma model, providing the first description of nanoscale aAPCs that lead to effective T cell stimulation and inhibition of tumor growth.

PDE5-Is for the Treatment of Concomitant ED and LUTS/BPH

Epidemiologic data in adult men exhibit a strong relationship between erectile dysfunction (ED) and lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH), indicating that men affected by ED should also be investigated for LUTS/BPH and those presenting with storage or voiding LUTS should be investigated for co-morbid ED. Common pathophysiolgical mechanisms underlying both LUTS/BPH and ED, including alteration of NO/cGMP or RhoA/Rho-kinase signaling and/or vascular or neurogenic dysfunction, are potential targets for proposed phosphodiesterase type 5 inhibitors (PDE5-Is). Several randomized controlled trials and only a few reviews including all commercially available PDE5-Is demonstrated the safety and efficacy of these drugs in the improvement of erectile function and urinary symptoms, in patients affected either by ED, LUTS, or both conditions.

Sprouty-2 and the MAPK/ERK pathway regulate polyfunctionality of virus-specific human T cells (P1006)

The ability for a single T cell to upregulate multiple effector functions, polyfunctionality, is crucial for protective immunity. Loss of polyfunctional T cells during chronic viral infections is associated with pathogen persistence and results in poor memory T cell formation and progressive T cell exhaustion. However, the molecular mechanisms determining the generation and maintenance of polyfunctional T cells remain unclear. We found that CD8+ T cell polyfunctionality can be directly regulated by antigen dose. High antigen dose stimulation induced robust T cell proliferation but, in contrast, only poorly polyfunctional T cells. Microarray analysis revealed that poorly polyfunctional T cells induced by high dose antigen had a unique transcription profile similar to exhausted T cells observed during chronic viral infections including upregulation of inhibitory receptors. However, the poorly polyfunctional T cell state was independent of inhibitory receptor signaling. Instead, biochemical and genetic experiments showed that the inhibition of MAPK/ERK pathway through upregulation of spry2, a negative regulator of the MAPK/ERK pathway, directly modulated polyfunctionality by selectively inhibiting cytokine secretion. Our findings reveal novel mechanisms controlling human T cell polyfunctionality and are directly relevant to effective vaccine development and T cell immunotherapy.