Lymphocytic Origin Research Articles

Identification of potential inhibitors for drug resistance in acute lymphoblastic leukemia through differentially expressed gene analysis and in silico screening

Acute lymphoblastic leukemia (ALL) is a disease of lymphocyte origin predominantly diagnosed in children. While its 5-year survival rate is high, resistance to chemotherapy drugs is still an obstacle. Our aim is to determine differentially expressed genes (DEGs) related to Asparaginase, Daunorubicin, Prednisolone, and Vincristine resistance and identify potential inhibitors via docking. Three datasets were accessed from the Gene Expression Omnibus database; GSE635, GSE19143, and GSE22529. The microarray data was analyzed using R4.2.0 and Bioconductor packages, and pathway and protein-protein interaction analysis were performed. We identified 1294 upregulated DEGs, with 12 genes consistently upregulated in all four resistant groups. KEGG analysis revealed an association with the PI3K-Akt pathway. Among DEGs, 33 hub genes including MDM2 and USP7 were pinpointed. Within common genes, CLDN9 and HS3ST3A1 were subjected to molecular docking against 3556 molecules. Following ADMET analysis, three drugs emerged as potential inhibitors: Flunarizine, Talniflumate, and Eltrombopag. Molecular dynamics analysis for HS3ST3A1 indicated all candidates had the potential to overcome drug resistance, Eltrombopag displaying particularly promising results. This study promotes a further understanding of drug resistance in ALL, introducing novel genes for consideration in diagnostic screening. It also presents potential inhibitor candidates to tackle drug resistance through repurposing.

Autoantigen Exposure in Murine Fetuses Elicited Nonpathogenic Autoimmunity

Autoimmunity refers to the presence of autoantibodies and autoreactive lymphocytes against the structural molecules of an individual's cells or tissues, known as self-antigens or autoantigens. It might exist in the absence of autoimmune disease. However, how autoimmunity develops remains a mystery, despite the discovery of autoantibodies in human cord blood. Murine fetuses on day 14 of gestation were subjected to intraperitoneal injection of murine thyroid peroxidase (TPO) peptides or collagen type II (CII) at graded doses via transuterine approach. Postnatally, the recipients were examined for autoantibodies by ELISA and autoreactive lymphocytes by in vitro incorporation of tritium and for the development of autoimmune thyroiditis or arthritis. At one month of age, the recipients did not secrete significant levels of anti-TPO or CII IgG2a in sera until a dose of 0.5 µg TPO or 5.0 µg CII was injected in utero. Serum anti-TPO or CII IgG2a persisted for at least two to four months postnatally. In recipients with elevated autoantibodies, their lymphocytes also showed proliferative responses specifically to TPO or CII. However, the development of autoantibodies and autoreactive lymphocytes was not associated with inflammatory cell infiltration of thyroid glands or paw joints even though anti-TPO or CII IgG2a was enhanced by postnatal TPO or CII challenge. Fetal exposure to free autoantigens could be immunogenic, shedding new light on the in utero origin of autoantibodies and autoreactive lymphocytes. The development of autoimmunity requires a threshold intensity of autoantigen exposure in the fetus.

Posttransplant Cutaneous Anaplastic Large Cell Lymphoma

Post-transplant lymphoproliferative disorders (PTLD) are frequent in organ recipients; they are most often of B lymphocyte origin; on the other hand, CD30+ t-cell PTLD remain rare; we report the observation of a case of CD30+ anaplastic large cell lymphoma in a renal transplant recipient.

Blebbing of the plasma membrane of lymphocytes as a marker of endothelial dysfunction in the development of post-resection insufficiency in patients with focal liver lesions

Purpose of the study. To evaluate the intensity of blebbing of the plasma membrane of lymphocytes and the formation of microparticles of lymphocytic origin in patients with postresection hepatic failure. Material and methods. The study involved 54 patients with focal liver diseases. The study involved 32 (59%) women, 22 (41%) men. The average age was 59.5 [49.75; 66,00]. Patients were divided into groups, 1 group - 10 patients with developed acute liver failure and 2 group - 44 patients with a favorable course of postoperative period. The following surgical interventions were performed: 36 (67%) patients underwent surgery - laparotomy, segmental liver resection, 10 (18%) - left-sided hemihepatectomy and 8 (15%) - right-sided hemihepatectomy. Results. Predictors of early postoperative hepatic failure are a decrease in initial blebbing and an increase in terminal blebbing and free microparticles of lymphocytic origin. Conclusions. Thus, changes in lymphocyte blebbing and the presence of free microparticles of lymphocytic origin are due to the development of endothelial insufficiency and apoptosis of lymphocytes in the context of liver failure and are determined by the reduced function of residual liver volume.

The Treatment of Non-Hodgkin's Lymphomas

The non-Hodgkin's lymphomas are a heterogeneous group of diseases. Cell marker studies over the past 10-15 years have demonstrated that the majority of adult B cell lymphomas are of B lymphocyte origin while a minority are of T lymphocyte origin. They vary in their prognosis according to histologic and clinical features.

Galectin-9 as a Potential Modulator of Lymphocyte Adhesion to Endothelium via Binding to Blood Group H Glycan.

The recruitment of leukocytes from blood is one of the most important cellular processes in response to tissue damage and inflammation. This multi-step process includes rolling leukocytes and their adhesion to endothelial cells (EC), culminating in crossing the EC barrier to reach the inflamed tissue. Galectin-8 and galectin-9 expressed on the immune system cells are part of this process and can induce cell adhesion via binding to oligolactosamine glycans. Similarly, these galectins have an order of magnitude higher affinity towards glycans of the ABH blood group system, widely represented on ECs. However, the roles of gal-8 and gal-9 as mediators of adhesion to endothelial ABH antigens are practically unknown. In this work, we investigated whether H antigen-gal-9-mediated adhesion occurred between Jurkat cells (of lymphocytic origin and known to have gal-9) and EA.hy 926 cells (immortalized endothelial cells and known to have blood group H antigen). Baseline experiments showed that Jurkat cells adhered to EA.hy 926 cells; however when these EA.hy 926 cells were defucosylated (despite the unmasking of lactosamine chains), adherence was abolished. Restoration of fucosylation by insertion of synthetic glycolipids in the form of H (type 2) trisaccharide Fucα1-2Galβ1-4GlcNAc restored adhesion. The degree of lymphocyte adhesion to native and the "H-restored" (glycolipid-loaded) EA.hy 926 cells was comparable. If this gal-9/H (type 2) interaction is similar to processes that occur in vivo, this suggests that only the short (trisaccharide) H glycan on ECs is required.

Plasma Pattern of Extracellular Vesicles Isolated from Hepatitis C Virus Patients and Their Effects on Human Vascular Endothelial Cells.

Hepatitis C virus (HCV) patients are at increased risk of cardiovascular disease (CVD). In this study, we aimed to evaluate the role of extracellular vesicles (EVs) as pathogenic factors for the onset of HCV-related endothelial dysfunction. Sixty-five patients with various stages of HCV-related chronic liver disease were enrolled in this case series. Plasma EVs were characterized and used to stimulate human vascular endothelial cells (HUVEC), which were examined for cell viability, mitochondrial membrane potential, and reactive oxygen species (ROS) release. The results showed that EVs from HCV patients were mainly of endothelial and lymphocyte origin. Moreover, EVs were able to reduce cell viability and mitochondrial membrane potential of HUVEC, while increasing ROS release. Those harmful effects were reduced by the pretreatment of HUVEC with the NLR family pyrin domain containing 3 (NLRP3)/AMP-activated protein kinase and protein kinase B blockers. In conclusion, in HCV patients, we could highlight a circulating pattern of EVs capable of inducing damage to the endothelium. These data represent a novel possible pathogenic mechanism underlying the reported increase of CVD occurrence in HCV infection and could be of clinical relevance also in relation to the widespread use of antiviral drugs.

T-cell Lymphoma in the Nasal Cavity in Goat

Background: Lymphomas are considered uncommon in goats, being the multicentric form with the highest number of cases for the species. Primary intranasal lymphomas are often diagnosed in dogs, cats, and humans. In the literature, there is only a description of a multicentric case involving the frontal sinuses and mucosa of the nasal cavity in a goat; therefore, it is important to describe unusual cases of this disease for the inclusion of new clinical and pathological characteristics in the ruminant clinic medicine. The objective of this work is to describe a case of T-cell lymphoma in the nasal cavity of a young goat.Case: The animal had dyspnea and respiratory noise for 15 days. Clinical examination showed nodulation in the right nasal cavity associated with serosanguinous secretion. Tracheostomy was performed; however, after 30 days the animal was euthanized. A sagittal plane of the head showed a pinkish-gray mass in the right and left nasal cavity, with a smooth, multilobulated surface, smooth adhering to the rostral portion of the dorsal concha and occluding the dorsal nasal meatus. Submandibular lymph nodes were slightly enlarged. Histopathological examination of the nasal cavity revealed a non-encapsulated, poorly delimited and ulcerated tumor composed of round cells arranged in a mantle supported by a discrete fibrovascular stroma extending the mucosa and lamina propria. Cells were round with sparse, eosinophilic and poorly delimited cytoplasm. Nuclei varied from round to elongated with condensed chromatin and evident nucleoli. Occasionally, aberrant nuclei, reniform shape and multinucleated cells were seen. Pleomorphism was moderate characterized by anisocytosis and anisocariosis. Typical and atypical mitosis were frequent (0-4 per field of highest magnification [400x]). Amidst the neoplasm, there were multifocal areas of necrosis and hemorrhage associated with a mild lymphocytic inflammatory infiltrate. Immunohistochemistry showed positive immunostaining for Vimentin antibodies and CD3, and negative for pan CK and CD20.Discussion: The lymphomas immunophenotyping is little used when it comes to farm animals, and there are few studies that use this technique for the definitive diagnosis of these neoplasms for small ruminants. The use of this technique must be considered in each case, in order to determine the pathogenesis, the accurate diagnosis and the origin of the neoplastic lymphocytes. In goats, T-cell lymphomas are the most diagnosed, although cases of multicentric B-cell lymphomas with ocular involvement have been diagnosed. In view of the clinical picture of the case described, infectious rhinitis already described in goats, such as aspergillosis and protothecosis, should be included as differential diagnoses. However, the anatomopathological findings facilitate the direction of the diagnosis, since infectious rhinitis presents as nodules / ulcerated masses or focal areas of necrosis associated with purulent secretion and in the histopathological examination it is possible to observe the intralesional etiological agents. In addition, the enzootic ethmoidal tumor must be included, as it has similar clinical signs and affects young animals, but they are adenomas/adenocarcinomas that affect the ethmoidal nasal shells induced by a retrovirus. Lymphomas in the caprine species are rare in the Northeastern semi-arid, but that in the present diagnostic routine occasionally occurs, being important the first description of its nasal shape for its inclusion in the differential diagnoses of diseases that present with clinical obstruction and dyspnea for the species. Keywords: hematopoietic neoplasia, immunophenotyping, lymphocytes, dyspnea.Descritores: neoplasia hematopoietica, imunofenotipagem, linfócitos, dispneia.Título: Linfoma de células T na cavidade nasal de caprino.

The Burden of COVID-19 in Adult Patients With Hematological Malignancies: A Single-center Experience After the Implementation of Mass-vaccination Programs Against SARS-CoV-2.

Despite the widespread mass-vaccination programs worldwide and the continuing evolution of COVID-19 therapeutics, the burden of SARS-CoV-2 infection in patients with hematological malignancies (HM) remains elusive. The aim of the present study was to assess the clinical characteristics, outcomes and therapeutic strategies applied in HM patients hospitalized during the post-vaccine period in Greece. From June 2021 to October 2022, 60 HM patients with COVID-19 were retrospectively analyzed. Exploratory end-points included the incidence of intubation, probability of recovery, mortality, and duration of remdesivir (RDV) administration. Overall, mechanical ventilation (MV) was required for five patients and crude mortality was 8.3%. HM of lymphocytic origin (p=0.035) and obesity (p=0.03) were the main determinants of the risk of intubation and among several laboratory markers, only LDH>520 IU/l was proven to be an independent MV predictor (p=0.038). The number of co-existing comorbidities (p=0.05) and disease severity on admission (p<0.001) were found to rule the probability of recovery, and dexamethasone was associated with worse prognosis, particularly in patients with mild/moderate COVID-19. RDV was administered to the entire cohort, of whom 38 were managed with an extended course. In the multivariate analysis, patients with HM of lymphocytic origin were more likely to receive RDV for more than five days (p=0.002). Our study emphasizes the frailty of HM patients, even in the era of Omicron-variant predominance, and underlines the need to optimize therapy.

Mendacious conjunctival lesions – A tale of two cases

Presentation of conjunctival tumors ranges from benign lesions like pinguecula and pterygium to highly malignant tumors of melanocytic, lymphoid, and stratified squamous epithelium origin. A 30-year-old female presented with two brown-colored conjunctival lesions in her left eye extending from medial canthus to limbus. Lesions were excised and subjected to histopathologic examination (HPE), which came out to be pigmented squamous cell papilloma, a rare conjunctival lesion having potential to convert to malignancy. Another 50-year-old female presented with pinguicula-like lesions in both her eyes along with maculopapular rash on her forehead. Conjunctival lesions were completely excised HPE, revealed Spiegler–Fendt sarcoid, also known as lymphocytoma cutis, along with conjunctival tumor of lymphocytic origin. Spiegler–Fendt sarcoid is usually a benign lesion with potential for systemic involvement requiring holistic approach for the management of such patients.

Immune checkpoints in T cells during oncogenic γ-herpesvirus infections.

Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) are two persistent oncogenic γ-herpesviruses with an exclusive tropism for humans. They cause cancers of lymphocyte, epithelial and endothelial cell origin, such as Burkitt's and Hodgkin's lymphoma, primary effusion lymphoma, nasopharyngeal carcinoma, and Kaposi sarcoma. Mutations in immune-related genes but also adverse events during immune checkpoint inhibition in cancer patients have revealed molecular requirements for immune control of EBV and KSHV. These include costimulatory and coinhibitory receptors on T cells that are currently explored or already therapeutically targeted in tumor patients. This review discusses these co-receptors and their influence on EBV- and KSHV-associated diseases. The respective studies reveal surprising specificities of some of these receptors for immunity to these tumor viruses, benefits of their blockade for some but not other virus-associated diseases, and that EBV- and KSHV-specific immune control should be monitored during immune checkpoint inhibition to prevent adverse events that might be associated with their reactivation during treatment.

Bridging Insights From Lymph Node and Synovium Studies in Early Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease of unknown etiology characterized by inflammation of the peripheral synovial joints leading to pannus formation and bone destruction. Rheumatoid Factor (RF) and anti-citrullinated protein antibodies (ACPA) are present years before clinical manifestations and are indicative of a break in tolerance that precedes chronic inflammation. The majority of studies investigating disease pathogenesis focus on the synovial joint as target site of inflammation while few studies explore the initial break in peripheral tolerance which occurs within secondary lymphoid organs such as lymph nodes. If explored during the earliest phases of RA, lymph node research may provide innovative drug targets for disease modulation or prevention. RA research largely centers on the role and origin of lymphocytes, such as pro-inflammatory T cells and macrophages that infiltrate the joint, as well as growing efforts to determine the role of stromal cells within the synovium. It is therefore important to explore these cell types also within the lymph node as a number of mouse studies suggest a prominent immunomodulatory role for lymph node stromal cells. Synovium and proximal peripheral lymph nodes should be investigated in conjunction with one another to gain understanding of the immunological processes driving RA progression from systemic autoimmunity toward synovial inflammation. This perspective seeks to provide an overview of current literature concerning the immunological changes present within lymph nodes and synovium during early RA. It will also propose areas that warrant further exploration with the aim to uncover novel targets to prevent disease progression.

Diffuse large B cell lymphoma and a novel gammaherpesvirus in northern elephant seals Mirounga angustirostris.

Two emaciated male northern elephant seal (NES) Mirounga angustirostris pups were admitted to The Marine Mammal Center (Sausalito, California, USA) and treated for malnutrition. Complete blood counts showed a progressive moderate to marked leukocytosis characterized by a predominance of large monomorphic mononuclear cells of probable lymphoid origin, frequently with flower-shaped nuclei. Both seals were euthanized due to suspected lymphoid neoplasia. At necropsy, most lymph nodes in both pups were markedly enlarged, some with distinct white nodules, the spleens were diffusely enlarged, and the intestinal mucosae were thickened. Histopathologic features consistent with disseminated large cell lymphoma were identified to varying degrees of severity in lymph nodes, bone marrow, liver, tonsils, spleen, liver, intestines, kidneys, lower urinary tract, and several other organs. Immunohistochemical staining of neoplastic cells was most consistent with B lymphocyte origin, with most cells staining positively for Pax 5 and CD20 with admixed small CD3-positive T lymphocytes and CD204-positive macrophages. PCR and sequencing identified a novel gammaherpesvirus, herein called miroungine gammaherpesvirus 3, from affected tissues. This virus is in a clade outside of named genera that utilize hosts in the suborder Caniformia. The present study is the first description of diffuse large B cell lymphoma with leukemic manifestation and concomitant detection of a novel gammaherpesvirus in free-living NESs. Further research regarding the prevalence of this new gammaherpesvirus and its associated pathogenesis in this species is indicated.

Pediatric Lymphoid and Histiocytic Lesions in the Head and Neck.

Lymphoid and histiocytic lesions of the head and neck in pediatric patients is a fascinating topic as most of these lesions are benign, but that the neoplastic cases are essential to diagnose accurately for appropriate treatment. It is thought that 90% of children will have palpable lymph nodes between the ages of 4 to 8; most, but not all, are non-malignant and some resolve spontaneously without treatment. This paper will look at many of the benign and malignant lesions of both lymphocytic and histiocytic origin that present in the head and neck of children focusing on their diagnostic criteria. There is a very pertinent discussion of nonmalignant lymphoid proliferations, as infections and other reactive conditions dominate the pathology of pediatric lymphohistiocytic head and neck lesions. Discussion of those lymphomas which arise more frequently in the head and neck focuses on those seen in children and young adults such as classic Hodgkin lymphoma and Burkitt lymphoma, as well as new more controversial entities such as pediatric-type follicular lymphoma. Histiocytic lesions, both benign and malignant, are described and may be challenging to diagnose.

Ia Antigen Expression by Human Malignant Lymphomas: Correlation With Conventional Lymphoid Markers

The Ia (p23,30) antigens are useful in determining the B- or T-cell origin of normal peripheral blood lymphocytes. However, exceptions to the preferential B-cell expression of Ia antigens exist, i.e., many plasma cells are Ia– and T cells are rarely Ia+. Therefore, we investigated Ia expression (assayed by direct immunofluorescence using heteroantisera) by cells isolated from 33 malignant lymphomas and 7 benign lymph nodes. This was compared with surface immunoglobulin (SIg) and sheep erythrocyte (SRBC) receptor (E rosette) expression. Results with normal lymph nodes were similar to those described for peripheral blood. Most lymph node B cells were Ia+SIg+. Occasional Ia+SIg– B cells and rare Ia+ T cells were present. Ia antigens were expressed in parallel with SIg in 15 of 19 B-cell lymphomas. In 4 B-cell lymphomas, substantial numbers of neoplastic Ia+SIg– cells were also present, suggesting the presence of neoplastic cells at varying stages of differentiation. Heterogeneity was also seen in those lymphomas associated with monoclonal proteins, as small numbers of Ia+ and Ia– plasma cells were present. Seven cases expressed the T-cell (la–SIg–E+) phenotype. The common acute lymphoblastic leukemia phenotype (Ia+SIg–E–) was rarely expressed and may be uncommon among lymphomas. Three lymphomas expressing the Ia+E+ phenotype were shown to be B-cell malignancies whose SIg had SRBC specificity. One Ia 4 T-cell lymphoproliferative disorder was found. Thus, Ia antigens are useful B-cell markers in most instances. Furthermore, their enumeration allows the demonstration of phenotype heterogeneity in B-cell malignancies, analogous to that described for T-cell malignancies.

TAC induced cardiac hypertrophy leads to increased levels of circulating microvesicles

Abstract Introduction Cardiac hypertrophy and heart failure are wide spread diseases of elderly patients in the industrialised world and drive a majority of healthcare costs in these countries. Therefore, there is a high urgency to understand the development and progress of heart failure to find new therapeutic strategies especially in early stages. Microvesicles are involved in the development and propagation of almost all cardiac diseases and increased levels of circulating microvesicles can be found in blood of patients with chronic heart failure. To point out the underlying mechanisms and to provide a new animal model based approach, we investigated microvesicle (MV)-release in mice that underwent Transverse Aortic Constriction (TAC). TAC is a common method to induce cardiac hypertrophy and heart failure in mice by inducing pressure overload. We hypothesized that TAC leads to upregulation of total MV and MV of specific origin. Methods and results Wildtype C57BL/6 mice underwent TAC to induce cardiac hypertrophy and heart failure. After TAC, mice developed cardiac hypertrophy as determined by altered heart weight/ bodyweight ratio, end-diastolic and end-systolic diameter and decreased fractional shortening. Total numbers of circulating microvesicles were detected 1, 4 and 12 weeks after TAC. We found that total numbers of circulating macrovesicles raised in a time dependent manner. Similar observations could be done with samples stained for annexin V, although results were not significant. Moreover, microvesicles were stained with specific surface markers for lymphocyte (CD3), monocyte (CD14), endothelial cells (CD31), thrombocytes (CD41), B-cells (CD45) and neutrophils (Lys6). One week after TAC increased numbers of specific microvesicles could be detected which in the course declined rapidly. Only microvesicles subgroup of lymphocyte origin showed significant increase one week after TAC-OP. Conclusion In this study, we show that total number of circulating microvesicles raise after TAC over an observation period of 12 weeks. Furthermore, we found that increased numbers of circulating microvesicles of specific origin like lymphocytes, monocytes, endothelial cells, thrombocytes, B-cells and neutrophils showed a trend towards increased levels one week after TAC with a rapid decline in subsequent detection. To our knowledge this is the first time that the impact of TAC on number of circulating microvesicles in mice was investigated. Future studies should characterize the content and effects of these MV on recipient cells to elucidate possible contributions to heart failure progression or protective effects. Detecting new harmful or protective effects of heart failure triggered by circulating microvesicles could offer new highly needed approaches to suppress heart failure development or deliver the possibility to develop new drugs for heart failure treatment. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Else Kröner-Fresenius

Abstract LB-089: Targeting transferrin receptor 1 (TfR1) with the ch128.1/IgG1 antibody inhibits Epstein-Barr virus (EBV) driven lymphoproliferative growth and lymphomagenesis in immunosuppressed mice bearing human B cells

Abstract Epstein-Barr virus (EBV) is a human herpesvirus that is associated with malignancies of both B lymphocyte and epithelial cell origin. EBV is associated with the development of approximately 1.5% of all cancers worldwide, including AIDS-related non-Hodgkin lymphoma (AIDS-NHL), Hodgkin lymphoma (HL), and post-transplant lymphoproliferative disease (PTLD). Primary infection of B cells with EBV results in their polyclonal activation and immortalization. The transferrin receptor 1 (TfR1), also known as CD71, is important for iron uptake and regulation of cellular proliferation. The TfR1 is expressed at high levels in proliferating cells including activated lymphocytes and malignant cells. We have developed a mouse/human chimeric antibody targeting TfR1 (ch128.1/IgG1) that has shown significant anti-tumor activity in immunosuppressed mouse models bearing human malignant B cells, including multiple myeloma and AIDS-NHL cells. In this study, we examined the effect of targeting TfR1 to inhibit EBV driven transformation of human B cells in vivo using an immunodeficient NSG mouse model. T cell-depleted human peripheral blood mononuclear cells were infected by exposure to EBV-containing supernatants from a B-lymphoblastoid cell line (B95-8). Mice were inoculated with these cells immediately following infection with EBV (day 0), or after cells were cultured for 7 days post infection prior to injection (day 7), and treated with ch128.1/IgG1 or an IgG1 isotype control antibody at 2 and 28 days post-inoculation. We monitored survival, serum levels of human cytokines, and characterized tumor-like growths in spleen and liver by assessing expression of human CD19 (marker for human B cells), EBV latent membrane protein 1 (LMP1; a marker for EBV infection), and human immunoglobulin light chain kappa or lambda (markers for monoclonality) by immunohistochemistry. Treatment with ch128.1/IgG1 significantly enhanced survival, compared to mice treated with the isotype control IgG1. Lymphoma-like cells of human B cell origin that were EBV-LMP1-positive, and often monoclonal, developed in most mice injected with EBV-infected cells (day 0 and 7) treated with the IgG1 control antibody, but only rarely in ch128.1/IgG1 treated animals. In addition, serum levels of human IL-6, IL-8, IFN-γ, CXCL13, sCD25, and sCD27, indicators of human B cell activation and proliferation, were lower in animals treated with ch128.1/IgG1. Taken together, these results show that ch128.1/IgG1 inhibited EBV driven lymphomagenesis using the NSG mouse model newly adapted to study EBV infection/transformation, indicating that there is significant potential for agents targeting TfR1 as therapeutic strategies to prevent EBV-associated B cell malignancies, including AIDS-NHL, HL, and PTLD. Citation Format: Laura E. Martinez, Tracy R. Daniels-Wells, Yu Guo, Larry I. Magpantay, Pierre V. Candelaria, Manuel L. Penichet, Otoniel Martinez-Maza, Marta Epeldegui. Targeting transferrin receptor 1 (TfR1) with the ch128.1/IgG1 antibody inhibits Epstein-Barr virus (EBV) driven lymphoproliferative growth and lymphomagenesis in immunosuppressed mice bearing human B cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-089.

A universal reporter cell line for bioactivity evaluation of engineered cytokine products

Engineered cytokine products represent a growing class of therapeutic proteins which need to be tested for biological activity at various stages of pharmaceutical development. In most cases, dedicated biological assays are established for different products, in a process that can be time-consuming and cumbersome. Here we describe the development and implementation of a universal cell-based reporter system for various classes of immunomodulatory proteins. The novel system capitalizes on the fact that the signaling of various types of pro-inflammatory agents (e.g., cytokines, chemokines, Toll-like receptor agonists) may involve transcriptional activation by NF-κB. Using viral transduction, we generated stably-transformed cell lines of B or T lymphocyte origin and compared the new reporter cell lines with conventional bioassays. The experimental findings with various interleukins and with members of the TNF superfamily revealed that the newly-developed “universal” bioassay method yielded bioactivity data which were comparable to the ones obtained with dedicated conventional methods. The engineered cell lines with reporters for NF-κB were tested with several antibody-cytokine fusions and may be generally useful for the characterization of novel immunomodulatory products. The newly developed methodology also revealed a mechanism for cytokine potentiation, based on the antibody-mediated clustering of TNF superfamily members on tumor-associated extracellular matrix components.

Impact and Intricacies of Bone Marrow Microenvironment in B-cell Lymphomas: From Biology to Therapy.

Lymphoma, a group of widely prevalent hematological malignancies of lymphocyte origin, has become the focus of significant clinical research due to their high propensity for refractory/relapsed (R/R) disease, leading to poor prognostic outcomes. The complex molecular circuitry in lymphomas, especially in the aggressive phenotypes, has made it difficult to find a therapeutic option that can salvage R/R disease. Furthermore, the association of lymphomas with the Bone Marrow (BM) microenvironment has been found to portend worse outcomes in terms of heightened chances of relapse and acquired resistance to chemotherapy. This review assesses the current therapy options in three distinct types of lymphomas: diffuse large B-cell lymphoma, follicular lymphoma and mantle cell lymphoma. It also explores the role of the BM tumor microenvironment as a secure ‘niche’ for lymphoma cells to grow, proliferate and survive. It further evaluates potential mechanisms through which the tumor cells can establish molecular connections with the BM cells to provide pro-tumor benefits, and discusses putative therapeutic strategies for disrupting the BM-lymphoma cell communication.

Dipyridamole as a new drug to prevent Epstein-Barr virus reactivation

Epstein-Barr virus (EBV) is a widely distributed gamma-herpesvirus that has been associated with various cancers mainly from lymphocytic and epithelial origin. Although EBV-mediated oncogenesis has been associated with viral oncogenes expressed during latency, a growing set of evidence suggested that antiviral treatments directed against EBV lytic phase may contribute to prevent some forms of cancers, including EBV-positive Post-Transplant Lymphoproliferative Diseases. It is shown here that dipyridamole (DIP), a safe drug with favorable and broad pharmacological properties, inhibits EBV reactivation from B-cell lines. DIP repressed immediate early and early genes expression mostly through its ability to inhibit nucleoside uptake. Considering its wide clinical use, DIP repurposing could shortly be evaluated, alone or in combination with other antivirals, to treat EBV-related diseases where lytic replication plays a deleterious role.