Effector Cell Populations Research Articles

Immunological consequences following splenectomy in patients with liver cirrhosis.

The immune status in patients with liver cirrhosis is generally impaired due to concomitant hypersplenism. As the spleen is the largest lymphoid organ, deleterious events resulting from splenectomy are of concern in these patients. However, the immunological consequences after splenectomy have not yet been fully elucidated. In the present study, the immune status after splenectomy was comprehensively examined. Splenectomy was performed in 11 patients with liver cirrhosis and hypersplenism, and the immune status in peripheral blood was examined and compared before and at 1, 3 and 6 months after splenectomy. Splenectomy significantly lowered the neutrophil-to-lymphocyte ratio, due to a surge in lymphocytes in the peripheral circulation at 3 and 6 months after splenectomy. The frequency of cluster of differentiation (CD)4+ T cells decreased after splenectomy, whereas the frequency of CD8+ T cells increased. Notably, the frequencies of the naïve and central memory subsets of CD4+ and CD8+ T cells decreased, whereas those of the effector memory subset trended upward. In addition, the frequencies of other immune cells such as γδ T cells, natural killer T cells and natural killer cells transiently increased, while inhibitory cells such as regulatory T cells and myeloid-derived suppressor cells significantly decreased. T-cell responses to viral- and tumor-associated antigens increased after splenectomy in five of eight and two of five patients, respectively. To the best of our knowledge, this is the first study to precisely examine the drastic changes of immunological phenotypes in peripheral blood after splenectomy in patients with cirrhosis. Our findings suggested that splenectomy in patients with cirrhosis may ameliorate the impaired immune status, possibly by reducing suppressive cells and enhancing the effector cell population and function, which could, at least in part, explain the mechanisms responsible for the clinical benefits of splenectomy.

Mathematical Modeling Reveals That the Administration of EGF Can Promote the Elimination of Lymph Node Metastases by PD-1/PD-L1 Blockade.

In the advanced stages of cancers like melanoma, some of the malignant cells leave the primary tumor and infiltrate the neighboring lymph nodes (LNs). The interaction between secondary cancer and the immune response in the lymph node represents a complex process that needs to be fully understood in order to develop more effective immunotherapeutic strategies. In this process, antigen-presenting cells (APCs) approach the tumor and initiate the adaptive immune response for the corresponding antigen. They stimulate the naive CD4+ and CD8+ T lymphocytes which subsequently generate a population of helper and effector cells. On one hand, immune cells can eliminate tumor cells using cell-cell contact and by secreting apoptosis inducing cytokines. They are also able to induce their dormancy. On the other hand, the tumor cells are able to escape the immune surveillance using their immunosuppressive abilities. To study the interplay between tumor progression and the immune response, we develop two new models describing the interaction between cancer and immune cells in the lymph node. The first model consists of partial differential equations (PDEs) describing the populations of the different types of cells. The second one is a hybrid discrete-continuous model integrating the mechanical and biochemical mechanisms that define the tumor-immune interplay in the lymph node. We use the continuous model to determine the conditions of the regimes of tumor-immune interaction in the lymph node. While we use the hybrid model to elucidate the mechanisms that contribute to the development of each regime at the cellular and tissue levels. We study the dynamics of tumor growth in the absence of immune cells. Then, we consider the immune response and we quantify the effects of immunosuppression and local EGF concentration on the fate of the tumor. Numerical simulations of the two models show the existence of three possible outcomes of the tumor-immune interactions in the lymph node that coincide with the main phases of the immunoediting process: tumor elimination, equilibrium, and tumor evasion. Both models predict that the administration of EGF can promote the elimination of the secondary tumor by PD-1/PD-L1 blockade.

Mucosal Immunity in HIV/SIV Infection: T Cells, B Cells and Beyond.

As our understanding of mucosal immunity increases, it is becoming clear that the host response to HIV-1 is more complex and nuanced than originally believed. The mucosal landscape is populated with a variety of specialized cell types whose functions include combating infectious agents while preserving commensal microbiota, maintaining barrier integrity, and ensuring immune homeostasis. Advances in multiparameter flow cytometry, gene expression analysis and bioinformatics have allowed more detailed characterization of these cell types and their roles in host defense than was previously possible. This review provides an overview of existing literature on immunity to HIV-1 and SIVmac in mucosal tissues of the female reproductive tract and the gastrointestinal tract, focusing on major effector cell populations and briefly summarizing new information on tissue resident memory T cells, Treg, Th17, Th22 and innate lymphocytes (ILC), subsets that have been studied primarily in the gastrointestinal mucosa.

Inhibition of class I HDACs attenuates renal interstitial fibrosis in a murine model

Renal interstitial fibrosis is the most common of all the forms of chronic kidney disease (CKD). Research has shown that histone deacetylases (HDACs) participate in the process leading to renal fibrosis. However, the effects of class I HDAC inhibitors on the mechanisms of onset and progression of renal interstitial fibrosis are still unclear. Here, we present the effects and mechanisms of action of FK228 (a selective inhibitor of class I HDACs) in the murine model of unilateral ureteral obstruction (UUO) and in vitro models. We investigated the antifibrotic role of FK228 in a murine model of UUO. We used two key effector cell populations, rat renal interstitial fibroblasts and renal tubular epithelial cells exposed to recombinant transforming growth factor-beta 1 (TGF-β1), to explore the mechanistic pathways among in vitro models.The results indicated that FK228 significantly suppressed the production of extracellular matrix (ECM) in both in vivo and in vitro models. FK228 inhibited renal fibroblast activation and proliferation and increased the acetylation of histone H3. We found that FK228 also inhibited the small mothers against decapentaplegic (Smad) and non-Smad signaling pathways. So FK228 could significantly suppress renal interstitial fibrosis via Smad and non-Smad pathways. FK228 may be the basis for a new and effective medicine for alleviating renal fibrosis in the future.

Ectonucleotidase Expression on Human Amnion Epithelial Cells: Adenosinergic Pathways and Dichotomic Effects on Immune Effector Cell Populations.

This study investigates the mechanism(s) underlying the immunoregulatory activities of placenta-derived human amnion epithelial cells (hAEC). The working hypothesis is that NAD+ and ATP, along with ectoenzymes involved in their metabolism, play a significant role in hAEC-mediated immune regulation. Proof of principle of the hypothesis was obtained by analyzing the interactions between hAEC and the main human leukocyte populations. The results obtained indicate that hAEC constitutively express a unique combination of functional ectoenzymes, driving the production of adenosine (ADO) via canonical (CD39, CD73) and alternative (CD38, CD203a/PC-1, CD73) pathways. Further, the picture is completed by the observation that hAEC express A1, A2a, and A2b ADO receptors as well as ADO deaminase, the enzyme involved in ADO catabolism. The contribution of the purinergic mediator to immunomodulation was confirmed by exposing in vitro different immune effector cells to the action of primary hAECs. B cells showed an enhanced proliferation and diminished spontaneous apoptosis when in contact with hAEC. T cell proliferation was partially inhibited by hAEC through ADO production, as confirmed by using specific ectoenzyme inhibitors. Further, hAEC induced an expansion of both T and B regulatory cells. Last, hAEC inhibited NK cell proliferation. However, the involvement of ADO-producing ectoenzymes is less apparent in this context. In conclusion, hAEC exert different in vitro immunoregulatory effects, per se, as a result of interactions with different populations of immune effector cells. These results support the view that hAEC are instrumental for regenerative medicine as well as in therapeutic applications for immune-related diseases.

T Cell Metabolism and Memory

Lymphocyte activation leads to rapid proliferation and differentiation and we have shown that CD4 T cell subsets are metabolically distinct. These specific metabolic programs may allow new understanding and approaches to manipulate immunity. Using metabolic network analysis of metabolomics and proteomics we defined several metabolic nodes differentially utilized by CD4 T cell subsets, including glutamine metabolism. By genetically deleting the glucose transporter Glut1 or the glutaminolysis enzyme, Glutaminase (GLS), we have shown that glycolysis and glutaminolysis are both used by activated T cells. All effector T cells require glycolysis, but we found that Th17 cells preferentially require GLS while Th1 cells are actively impaired by this enzyme. Thus, inhibition of GLS both reduces Th17 responses and promotes differentiation of Th1 cells and can lead to signs of T cell exhaustion. We show that GLS-deficiency can protect against Th17-mediated inflammatory models and also can augment effector function of Th1 CAR-T cells against B cell targets. Understanding mechanisms that regulate T cell metabolism may provide new tools to modulate immunity the balance of T cell effector populations to both suppress inflammation or promote effector function. DisclosuresRathmell:Calithera: Research Funding.

DOPS Adjuvant Confers Enhanced Protection against Malaria for VLP-TRAP Based Vaccines.

Vaccination remains the most effective and essential prophylactic tool against infectious diseases. Enormous efforts have been made to develop effective vaccines against malaria but successes remain so far limited. Novel adjuvants may offer a significant advantage in the development of malaria vaccines, in particular if combined with inherently immunogenic platforms, such as virus-like particles (VLP). Dioleoyl phosphatidylserine (DOPS), which is expressed on the outer surface of apoptotic cells, represents a novel adjuvant candidate that may confer significant advantage over existing adjuvants, such as alum. In the current study we assessed the potential of DOPS to serve as an adjuvant in the development of a vaccine against malaria either alone or combined with VLP using Plasmodium falciparum thrombospondin-related adhesive protein (TRAP) as a target antigen. TRAP was chemically coupled to VLPs derived from the cucumber mosaic virus fused to a universal T cell epitope of tetanus toxin (CuMVtt). Mice were immunized with TRAP alone or formulated in alum or DOPS and compared to TRAP coupled to CuMVtt formulated in PBS or DOPS. Induced immune responses, in particular T cell responses, were assessed as the major protective effector cell population induced by TRAP. The protective capacity of the various formulations was assessed using a transgenic Plasmodium berghei expressing PfTRAP. All vaccine formulations using adjuvants and/or VLP increased humoral and T cell immunogenicity for PfTRAP compared to the antigen alone. Display on VLPs, in particular if formulated with DOPS, induced the strongest and most protective immune response. Thus, the combination of VLP with DOPS may harness properties of both immunogenic components and optimally enhance induction of protective immune responses.

Update on PD-1/PD-L1 Inhibitors in Multiple Myeloma.

The treatment of cancer, especially of various types of solid tumors, has been revolutionized by the blockade of the PD-1/PD-L1 pathway by immune checkpoint inhibitors. Their success amongst hematologic malignancies, however, has been limited so far to the treatment of classic Hodgkin's lymphoma, which portrays a typical overexpression of PD-1 ligands (PD-L1, PD-L2) as a consequence of changes in chromosome 9p24.1. Their current application in multiple myeloma (MM) is rather uncertain, as discordant results have been reported by distinct research groups concerning especially the expression of PD-1/PD-L1 molecules on malignant plasma cells or on the responsible immune effector cell populations, respectively. In MM it seems that an approach based on combination treatment might be appropriate as unsatisfactory results have been yielded by monotherapy with PD-1/PD-L1 inhibitors. Immunomodulatory drugs, which are the current cornerstone of MM treatment, are the most logical partners as they possess many possibly synergistic effects. Nevertheless, the initially optimistic results have become disappointing due to the excessive and unpredictable toxicity of the combination of pembrolizumab with lenalidomide or pomalidomide. The FDA has suspended or put on hold several phase 3 trials in relapsed as well as in newly diagnosed myeloma patients. There are also other potentially synergistic and promising combinations, such as the anti-CD38 monoclonal antibody daratumumab, irradiation, etc. Not only the effective partner but also the correct timing of the initiation of the PD-1/PD-L1 inhibitors treatment seems to be of utmost importance. These strategies are currently being examined in various stages of myeloma such as during consolidation post autologous stem cell transplantation, targeting minimal residual disease or even in high risk smoldering myeloma.

RIVA \u2013 a phase IIa study of rituximab and varlilumab in relapsed or refractory B-cell malignancies: study protocol for a randomized controlled trial

BackgroundOver 12,000 new cases of B-cell malignancies are diagnosed in the UK each year, with diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) being the most common subtypes. Standard frontline therapy consists of immunochemotherapy with a CD20 monoclonal antibody (mAb), such as rituximab, delivered in combination with multi-agent chemotherapy. Despite being considered a treatable and potentially curable cancer, approximately 30% of DLBCL cases will relapse after frontline therapy. Advanced stage FL is incurable and typically has a relapsing and remitting course with a frequent need for re-treatment. Based on supportive preclinical data, we hypothesised that the addition of varlilumab (an anti-CD27 mAb) to rituximab (an anti-CD20 mAb) can improve the rate, depth and duration of the response of rituximab monotherapy in patients with relapsed or refractory B-cell malignancies.Methods/designCombination treatment of varlilumab plus rituximab, in two different dosing regimens, is being tested in the RIVA trial. RIVA is a two-stage open-label randomised phase IIa design in up to 40 patients with low- or high-grade relapsed or refractory CD20+ B-cell lymphoma. The study is open to recruitment in the UK. Enrolled patients are randomised 1:1 to two different experimental varlilumab to rituximab combinations.The primary objective is to determine the safety and tolerability of the combination and the anti-tumour activity (response) in relapsed or refractory B-cell malignancies. Secondary objectives will include an evaluation of the duration of the response and overall survival. Tertiary translational objectives include assessment of B-cell depletion, changes in immune effector cell populations, expression of CD27 as a biomarker of response and pharmacokinetic properties. Analyses will not be powered for formal statistical comparisons between treatment arms.DiscussionRIVA will determine whether the combination of rituximab and varlilumab in relapsed or refractory B-cell malignancies is active and safe prior to future phase II/III trials.Trial registrationEudraCT, 2017–000302-37. Registered on 16 January 2017. ISRCTN, ISRCTN15025004. Registered on 16 August 2017.

CD8+ lymphocyte control of SIV infection during antiretroviral therapy.

CD8+ lymphocytes play an important role in suppressing in vivo viral replication in HIV infection. However, both the extent to which and the mechanisms by which CD8+ lymphocytes contribute to viral control are not completely understood. A recent experiment depleted CD8+ lymphocytes in simian immunodeficiency virus (SIV)-infected rhesus macaques (RMs) on antiretroviral treatment (ART) to study the role of CD8+ lymphocytes. CD8+ lymphocytes depletion resulted in temporary plasma viremia in all studied RMs. Viral control was restored when CD8+ lymphocytes repopulated. We developed a viral dynamic model to fit the viral load (VL) data from the CD8 depletion experiment. We explicitly modeled the dynamics of the latent reservoir and the SIV-specific effector cell population including their exhaustion and their potential cytolytic and noncytolytic functions. We found that the latent reservoir significantly contributes to the size of the peak VL after CD8 depletion, while drug efficacy plays a lesser role. Our model suggests that the overall CD8+ lymphocyte cytolytic killing rate is dynamically changing depending on the levels of antigen-induced effector cell activation and exhaustion. Based on estimated parameters, our model suggests that before ART or without ART the overall CD8 cytolytic killing rate is small due to exhaustion. However, after the start of ART, the overall CD8 cytolytic killing rate increases due to an expansion of SIV-specific CD8 effector cells. Further, we estimate that the cytolytic killing rate can be significantly larger than the cytopathic death rate in some animals during the second phase of ART-induced viral decay. Lastly, our model provides a new explanation for the puzzling findings by Klatt et al. and Wong et al. that CD8 depletion done immediately before ART has no noticeable effect on the first phase viral decay slope seen after ART initiation Overall, by incorporating effector cells and their exhaustion, our model can explain the effects of CD8 depletion on VL during ART, reveals a detailed dynamic role of CD8+ lymphocytes in controlling viral infection, and provides a unified explanation for CD8 depletion experimental data.

Circulating monocyte subsets and heart failure prognosis.

Monocytes are a heterogeneous population of effector cells with key roles in tissue integrity restoration and maintenance. Here, we explore the association of monocyte subsets and prognosis in patients with ambulatory heart failure (HF). Monocyte subsets were classified as classical (CD14++/CD16–), intermediate (CD14++/CD16+), or non-classical (CD14+/CD16++). Percentage distribution and absolute cell count were assessed in each subset, and multivariable Cox regression analyses were performed with all-cause death, HF-related hospitalization, and the composite end-point of both as dependent variables. 400 patients were consecutively included (72.8% male, age 69.4±12.2 years, 45.5% from ischemic aetiology, left ventricle ejection fraction (LVEF) 41.6% ±14.5, New York Heart Association (NYHA) class II 62.8% and III 30.8%). During a mean follow-up of 2.6±0.9 years, 107 patients died, 99 had a HF-related hospitalization and 160 suffered the composite end-point of all-cause death or HF-related hospitalization. Monocyte subsets assessed in percentages were not independently associated to any of the end-points. When considering number of cells/μL, intermediate subset was independently associated with an increase of all-cause death (HR 1.25 [95% CI 1,02–1.52], p = 0.03), and the composite end-point HR 1.20 [95% CI 1,03–1.40], p = 0.02). The presented findings show that absolute cell count of monocyte subsets was preferred over monocyte percentage for prognosis stratification for outpatients with HF. The intermediate monocyte subset provides information on increased risk of all-cause death and the composite end-point.

Concerted IL-25R and IL-4Rα signaling drive innate type 2 effector immunity for optimal helminth expulsion.

Interleukin 25 (IL-25) is a major 'alarmin' cytokine, capable of initiating and amplifying the type immune response to helminth parasites. However, its role in the later effector phase of clearing chronic infection remains unclear. The helminth Heligmosomoides polygyrus establishes long-term infections in susceptible C57BL/6 mice, but is slowly expelled in BALB/c mice from day 14 onwards. We noted that IL-25R (Il17rb)-deficient BALB/c mice were unable to expel parasites despite type 2 immune activation comparable to the wild-type. We then established that in C57BL/6 mice, IL-25 adminstered late in infection (days 14-17) drove immunity. Moreover, when IL-25 and IL-4 were delivered to Rag1-deficient mice, the combination resulted in near complete expulsion of the parasite, even following administration of an anti-CD90 antibody to deplete innate lymphoid cells (ILCs). Hence, effective anti-helminth immunity during chronic infection requires an innate effector cell population that is synergistically activated by the combination of IL-4Rα and IL-25R signaling.

PD-1 Expression on Mycobacterium tuberculosis-Specific CD4 T Cells Is Associated With Bacterial Load in Human Tuberculosis.

Persistent antigen stimulation in chronic infections has been associated with antigen-specific T cell dysfunction and upregulation of inhibitory receptors, including programmed cell death protein 1 (PD-1). Pulmonary tuberculosis (TB) disease is characterized by high levels of Mycobacterium tuberculosis (Mtb), yet the relationship between bacterial load, PD-1 expression, and Mtb-specific T cell function in human TB has not been well-defined. Using peripheral blood samples from adults with LTBI and with pulmonary TB disease, we tested the hypothesis that PD-1 expression is associated with bacterial load and functional capacity of Mtb-specific T cell responses. We found that PD-1 was expressed at significantly higher levels on Th1 cytokine-producing Mtb-specific CD4 T cells from patients with smear-positive TB, compared with smear-negative TB and LTBI, which decreased after completion of anti-TB treatment. By contrast, expression of PD-1 on Mtb-specific CD8 T cells was significantly lower than on Mtb-specific CD4 T cells and did not differ by Mtb infection and disease status. In vitro stimulation of PBMC with Mtb antigens demonstrated that PD-1 is induced on proliferating Mtb-specific CD4 T cells and that Th1 cytokine production capacity is preferentially maintained within PD-1+ proliferating CD4 T cells, compared with proliferating Mtb-specific CD4 T cells that lack PD-1 expression. Together, these data indicate that expression of PD-1 on Mtb-specific CD4 T cells is indicative of mycobacterial antigen exposure and identifies a population of effector cells with Th1 cytokine production capacity. These studies provide novel insights into the role of the PD-1 pathway in regulating CD4 and CD8 T cell responses in Mtb infection and provide rationale for future studies to evaluate PD-1 expression on antigen-specific CD4 T cells as a potential biomarker for bacterial load and treatment response in human TB.

B cell adaptor for PI3-kinase (BCAP) modulates CD8+ effector and memory T cell differentiation.

CD8+ T cells respond to signals via the T cell receptor (TCR), costimulatory molecules, and immunoregulatory cytokines by developing into diverse populations of effector and memory cells. The relative strength of phosphoinositide 3-kinase (PI3K) signaling early in the T cell response can dramatically influence downstream effector and memory T cell differentiation. We show that initial PI3K signaling during T cell activation results in up-regulation of the signaling scaffold B cell adaptor for PI3K (BCAP), which further potentiates PI3K signaling and promotes the accumulation of CD8+ T cells with a terminally differentiated effector phenotype. Accordingly, BCAP-deficient CD8+ T cells have attenuated clonal expansion and altered effector and memory T cell development following infection with Listeria monocytogenes Thus, induction of BCAP serves as a positive feedback circuit to enhance PI3K signaling in activated CD8+ T cells, thereby acting as a molecular checkpoint regulating effector and memory T cell development.

The Transcription Factor Runx2 Is Required for Long-Term Persistence of Antiviral CD8+ Memory T Cells.

During acute lymphocytic choriomeningitis virus infection, pathogen-specific CD8+ cytotoxic T lymphocytes undergo clonal expansion leading to viral clearance. Following this, the majority of pathogen-specific CD8+ T cells undergo apoptosis, leaving a small number of memory CD8+ T cells that persist long-term and provide rapid protection upon secondary infection. Whereas much is known about the cytokines and transcription factors that regulate the early effector phase of the antiviral CD8+ T cell response, the factors regulating memory T cell homeostasis and survival are not well understood. In this article, we show that the Runt-related transcription factor Runx2 is important for long-term memory CD8+ T cell persistence following acute lymphocytic choriomeningitis virus-Armstrong infection in mice. Loss of Runx2 in T cells led to a reduction in KLRG1lo CD127hi memory precursor cell numbers with no effect on KLRG1hi CD127lo terminal effector cell populations. Runx2 expression levels were transcriptionally regulated by TCR signal strength via IRF4, TLR4/7, and selected cytokines. These data demonstrate a CD8+ T cell–intrinsic role for Runx2 in the long-term maintenance of antiviral memory CD8+ T cell populations.

Abstract 3965: Sequential multiplex immunofluorescence technology (SMIFT): A new staining strategy for immunotherapy

Abstract Introduction: Tumor tissues exhibit a multitude of different cell types that have extravasated from other regions in the body. These cells are likely to represent heterogeneous populations of immune and effector cells. Assessing immunotherapy markers in tissues could be of significant value for patient care. We therefore have developed an innovative method that will enable the application of three or more sequential mouse monoclonal antibody (MMA) applications that can detect these immune cells on a single tissue. Previous methods using a sequential staining technique of MMA required a manual application and time-consuming heating and stripping between steps. The assessment of multiple targets can now be determined in approximately eight hours using full automation without heating or stripping procedures. This method may be valuable when the quantification of specific immunotherapy markers is required. Materials/Methods: Two assays were developed using Sequential Multiplex Immunofluorescence Technology (SMIFT): FOXP3, CD163, PD-1, CD8 as well as p40, Desmoglein-3, TTF-1, CD8. Tissues were fixed in 10% NBF for 24 hours and processed into paraffin. Tissue sections were cut at 5 microns and adhered to glass slides. Sections were then heated in a citrate-based buffer at pH 6.0 within a pressure cooker at 95°C for 40 minutes. All antibodies were diluted in diluent and applied to tissues to determine optimal IF (and IHC) titers. Detection of each antibody was accomplished with commercially available anti-mouse/anti-rabbit HRP polymer followed by fluorophores 594, 488, 546 and 480 for IF (or by DAB for IHC comparison). A blocking reagent was incorporated into the protocol to prevent cross-reactivity of multiple detection fluorophores. Both assays were comprised of two sequential MMA followed by a third application of a mouse/rabbit monoclonal antibody cocktail to complete the procedure. Sections were then counterstained in DAPI (or hematoxylin). Results: Multiplexed staining intensities were compared to individual antibody formats for both assays. Staining of each target was clearly identified even when multiplexed. Fluorescence intensities were scored on a subjective scale from 1-3+ with 3 representing the highest intensity. Both assays exhibited 3-3+ staining intensities for each target fluorophore as well as in multiplexed formats. Individual IHC staining results were also comparable to individual and multiplexed IF targets with identical staining patterns. Conclusion: Multiplexing can be achieved using SMIFT, a sequential and multiplex approach for assays tested on a single tissue section. Three sequential applications of four antibodies can be performed in less than eight hours with full automation. This is in contrast to previous overnight methods. Most importantly, this approach could be used to assess immunotherapy markers in tissues and may provide prognostic or predictive value. Citation Format: Joseph Vargas, David Tacha, Julio Masabanda, Sarah Schollmeier, Cristin Douglas, George Yang. Sequential multiplex immunofluorescence technology (SMIFT): A new staining strategy for immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3965.

Timed Regulation of 3BP2 Induction Is Critical for Sustaining CD8+ T Cell Expansion and Differentiation

SUMMARYSuccessful anti-viral response requires the sustained activation and expansion of CD8+ T cells for periods that far exceed the time limit of physical T cell interaction with antigen-presenting cells (APCs). The expanding CD8+ T cell pool generates the effector and memory cell populations that provide viral clearance and long-term immunity, respectively. Here, we demonstrate that 3BP2 is recruited in cytoplasmic microclusters and nucleates a signaling complex that facilitates MHC:peptide-independent activation of signaling pathways downstream of the TCR. We show that induction of the adaptor molecule 3BP2 is a sensor of TCR signal strength and is critical for sustaining CD8+ T cell proliferation and regulating effector and memory differentiation.

Stem cell-like T-bet+ IgM memory cells generate multi-lineage effector B cells

Abstract Our laboratory has been studying the differentiation of CD11c+ T-bet+ IgM memory B cells during secondary ehrlichial infection. These cells are closely related to B cells that have been described in a range of other contexts, including hepatitis, AIDs, malaria, SLE, and age-related autoimmunity. Following secondary infection, IgM memory cells, as a population, undergo self-renewal, and differentiate into effector cells, including splenic and bone marrow antibody secreting cells (ASC). Moreover, IgM memory cells enter germinal centers, where they undergo class-switch recombination and give rise to class-switched memory and effector cells. Although these data suggest that a single memory cell has multi-lineage potential, we sought to formally address this question by searching for shared clones among IgM memory cell-derived effector cells. Among the IgM memory cell-derived subsets, we identified several clones common to all effector cell populations. The number of common clones varied for each pairwise comparison of effector cells and suggested lineal relationships. IgM memory cells accumulated mutations following rechallenge; although all memory cell-derived subsets displayed similar numbers of V region mutations. Lineage analysis demonstrated that the effector cell subsets underwent varying degrees of clonal diversification, although this was clone-dependent. These studies reveal that a single IgM memory cell clone can give rise to different memory and effector cell subsets, that is, they exhibit stem cell properties. This property distinguishes these T-bet+ IgM memory cells as a unique memory cell subset.

Visualizing the Immune System: Providing Key Insights into HIV/SIV Infections.

Immunological inductive tissues, such as secondary lymphoid organs, are composed of distinct anatomical microenvironments for the generation of immune responses to pathogens and immunogens. These microenvironments are characterized by the compartmentalization of highly specialized immune and stromal cell populations, as well as the presence of a complex network of soluble factors and chemokines that direct the intra-tissue trafficking of naïve and effector cell populations. Imaging platforms have provided critical contextual information regarding the molecular and cellular interactions that orchestrate the spatial microanatomy of relevant cells and the development of immune responses against pathogens. Particularly in HIV/SIV disease, imaging technologies are of great importance in the investigation of the local interplay between the virus and host cells, with respect to understanding viral dynamics and persistence, immune responses (i.e., adaptive and innate inflammatory responses), tissue structure and pathologies, and changes to the surrounding milieu and function of immune cells. Merging imaging platforms with other cutting-edge technologies could lead to novel findings regarding the phenotype, function, and molecular signatures of particular immune cell targets, further promoting the development of new antiviral treatments and vaccination strategies.

Allergen-Specific T Cells in IgE-Mediated Food Allergy.

Food allergy is the major reason for severe anaphylaxis in childhood and adolescence. Currently, effective and safe treatments for food allergy are unavailable. Allergen-specific CD4+ T cells have a pivotal role in causing and maintaining the allergic response to food allergens. The purpose of this review is to provide an overview on the role of allergen-specific T cells in food allergy during allergic sensitization, natural tolerance development and allergen immunotherapy. Allergen-specific T cells in the context of food allergy are predominantly of a Th2 type with slightly different surface marker expression patterns in different food allergies. During the process of reverting food allergy to a status of tolerance or sustained unresponsiveness there is a loss of this Th2 committed compartment with an asymptotic approximation to a regulatory and Th0/Th1 dominated compartment seen in non-allergic individuals. This process is accompanied by a significant reduction of absolute frequencies of allergen-specific T cells. Particularly, regulatory T cells may provide significant help to achieve sustained control of the effector cell populations via suppression of effector cell function and possibly induction of blocking antibodies.