Follicular Center Research Articles

B-cell lymphoma of the skin: clinical observation

Currently, there is an increase and an increase in the incidence of primary skin lymphomas worldwide. B-cell cutaneous lymphomas account for 25–30% of primary skin lymphomas. Among all skin lymphomas, primary cutaneous lymphoma from follicular center cells occurs in 10–11% of cases and is characterized by great diagnostic difficulties due to the great similarity of clinical manifestations with other dermatoses, such as benign lymphoplasia, Beck's sarcoidosis, Jessner–Kanof lymphocytic infiltration, skin metastases. This paper presents a clinical case of B-cell lymphoma in a 29-year-old woman with a lesion of the facial skin in the form of a node, initially incorrectly interpreted as benign lymphoplasia. For five years, the patient received therapy with topical glucocorticosteroids with no effect from. Subsequently, histological examination and immunohistochemistry were performed for the purpose of differential diagnosis of sarcoidosis with B-cell lymphoma. Histologically, there is nodular proliferation of atypical lymphoid cells in the dermis, most of which have cytological characteristics of a centrocyte with an admixture of a small number of central blasts. Nodular proliferates contain an admixture of compactly arranged small lymphocytes. There are no signs of epidermotropism. During immunohistochemical examination, cells forming nodular proliferates express CD20, bc16 with an index of proliferative activity for the expression of nuclear protein K167 ― 20–30%, a dissociated network of follicular dentritic cells expressing CD21 is determined at the base of nodular proliferates. They are not expressed by bc12, CD3, CD2, CD5 proliferate cells. CD117 is expressed by an admixture of discretely distributed mast cells. The morphological picture corresponds to primary cutaneous centrofollicular lymphoma. The node was excised. Radiation therapy was not prescribed due to the patient's pregnancy. This clinical observation highlights the importance of considering the diagnosis of lymphoma in the differential diagnosis of treatment-resistant dermatological diseases.

Sustained innate interferon is an essential inducer of tertiary lymphoid structures.

Tertiary lymphoid structures (TLS) resemble follicles of secondary lymphoid organs and develop in nonlymphoid tissues during inflammation and cancer. Which cell types and signals drive the development of TLS is largely unknown. To investigate early events of TLS development in the lungs, we repeatedly instilled p(I:C) plus ovalbumin (Ova) intranasally. This induced TLS ranging from lymphocytic aggregates to organized and functional structures containing germinal centers. We found that TLS development is independent of FAP+ fibroblasts, alveolar macrophages, or CCL19 but crucially depends on type I interferon (IFN-I). Mechanistically, IFN-I initiates two synergistic pathways that culminate in the development of TLS. On the one hand, IFN-I induces lymphotoxin (LT)α in lymphoid cells, which stimulate stromal cells to produce the B-cell-attracting chemokine CXCL13 through LTβR-signaling. On the other hand, IFN-I is sensed by stromal cells that produce the T-cell-attracting chemokines CXCL9, CXCL10 as well as CCL19 and CCL21 independently of LTβR. Consequently, B-cell aggregates develop within a week, whereas follicular dendritic cells and germinal centers appear after 3 weeks. Thus, sustained production of IFN-I together with an antigen is essential for the induction of functional TLS in the lungs.

Tlr9 deficiency in B cells leads to obesity by promoting inflammation and gut dysbiosis

Toll-like receptor 9 (TLR9) recognizes bacterial, viral and self DNA and play an important role in immunity and inflammation. However, the role of TLR9 in obesity is less well-studied. Here, we generate B-cell-specific Tlr9-deficient (Tlr9fl/fl/Cd19Cre+/-, KO) B6 mice and model obesity using a high-fat diet. Compared with control mice, B-cell-specific-Tlr9-deficient mice exhibited increased fat tissue inflammation, weight gain, and impaired glucose and insulin tolerance. Furthermore, the frequencies of IL-10-producing-B cells and marginal zone B cells were reduced, and those of follicular and germinal center B cells were increased. This was associated with increased frequencies of IFNγ-producing-T cells and increased follicular helper cells. In addition, gut microbiota from the KO mice induced a pro-inflammatory state leading to immunological and metabolic dysregulation when transferred to germ-free mice. Using 16 S rRNA gene sequencing, we identify altered gut microbial communities including reduced Lachnospiraceae, which may play a role in altered metabolism in KO mice. We identify an important network involving Tlr9, Irf4 and Il-10 interconnecting metabolic homeostasis, with the function of B and T cells, and gut microbiota in obesity.

A novel microporous biomaterial vaccine platform for long-lasting antibody mediated immunity against viral infection

Current antigen delivery platforms, such as alum and nanoparticles, are not readily tunable, thus may not generate optimal adaptive immune responses. We created an antigen delivery platform by loading lyophilized Microporous Annealed Particle (MAP) with aqueous solution containing target antigens. Upon administration of antigen loaded MAP (VaxMAP), the biomaterial reconstitution forms an instant antigen-loaded porous scaffold area with a sustained release profile to maximize humoral immunity. VaxMAP induced CD4+ T follicular helper (Tfh) cells and germinal center (GC) B cell responses in the lymph nodes similar to Alum. VaxMAP loaded with SARS-CoV-2 spike protein improved the magnitude, neutralization, and duration of anti-receptor binding domain antibodies compared to Alum vaccinated mice. A single injection of Influenza specific HA1-loaded-VaxMAP enhanced neutralizing antibodies and elicited greater protection against influenza virus challenge than HA1-loaded-Alum. Thus, VaxMAP is a platform that can be used to promote adaptive immune cell responses to generate more robust neutralizing antibodies, and better protection upon pathogen challenge.

Single-shot dendritic cell targeting SARS-CoV-2 vaccine candidate induces broad, durable and protective systemic and mucosal immunity in mice

Current coronavirus disease 2019 vaccines face limitations including waning immunity, immune escape by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, limited cellular response, and poor mucosal immunity. We engineered a Clec9A-receptor binding domain (RBD) antibody construct that delivers the SARS-CoV-2 RBD to conventional type 1 dendritic cells. Compared with non-targeting approaches, single dose immunization in mice with Clec9A-RBD induced far higher RBD-specific antibody titers that were sustained for up to 21months after vaccination. Uniquely, increasing neutralizing and antibody-dependent cytotoxicity activities across the sarbecovirus family was observed, suggesting antibody affinity maturation over time. Consistently and remarkably, RBD-specific follicular T helper cells and germinal center B cells persisted up to 12months after immunization. Furthermore, Clec9A-RBD immunization induced a durable mono- and poly-functional T-helper 1-biased cellular response that was strongly cross-reactive against SARS-CoV-2 variants of concern, including Omicron subvariants, and with a robust CD8+ Tcell signature. Uniquely, Clec9A-RBD single-shot systemic immunization effectively primed RBD-specific cellular and humoral immunity in lung and resulted in significant protection against homologous SARS-CoV-2 challenge as evidenced by limited body weight loss and approximately 2 log10 decrease in lung viral loads compared with non-immunized controls. Therefore, Clec9A-RBD immunization has the potential to trigger robust and sustained, systemic and mucosal protective immunity against rapidly evolving SARS-CoV2 variants.

Role of germinal center and CD39highCD73+ B cells in the age-related tonsillar involution

BackgroundThe tonsils operate as a protection ring of mucosa at the gates of the upper aero-digestive tract. They show similarities with lymph nodes and participate as inductive organs of systemic and mucosal immunity. Based on the reduction of their size since puberty, they are thought to experience involution in adulthood. In this context, we have used tonsillar mononuclear cells (TMC) isolated from patients at different stages of life, to study the effect of ageing and the concomitant persistent inflammation on these immune cells.ResultsWe found an age-dependent reduction in the proportion of germinal center B cell population (BGC) and its T cell counterpart (T follicular helper germinal center cells, TfhGC). Also, we demonstrated an increment in the percentage of local memory B cells and mantle zone T follicular helper cells (mTfh). Furthermore, younger tonsils rendered higher proportion of proliferative immune cells within the freshly isolated TMC fraction than those from older ones. We demonstrated the accumulation of a B cell subset (CD20+CD39highCD73+ cells) metabolically adapted to catabolize adenosine triphosphate (ATP) as patients get older. To finish, tonsillar B cells from patients at different ages did not show differences in their proliferative response to stimulation ex vivo, in bulk TMC cultures.ConclusionsThis paper sheds light on the changing aspects of the immune cellular landscape, over the course of time and constant exposure, at the entrance of the respiratory and digestive systems. Our findings support the notion that there is a re-modelling of the immune functionality of the excised tonsils over time. They are indicative of a transition from an effector type of immune response, typically oriented to reduce pathogen burden early in life, to the development of an immunosuppressive microenvironment at later stages, when tissue damage control gets critical provided the time passed under immune attack. Noteworthy, when isolated from such histologic microenvironment, older tonsillar B cells seem to level their proliferation capacity with the younger ones. Understanding these features will not only contribute to comprehend the differences in susceptibility to pathogens among children and adults but would also impact on vaccine developments intended to target these relevant mucosal sites.

PRMT5 Promotes T follicular helper Cell Differentiation and Germinal Center Responses during Influenza Virus Infection.

Protein arginine methyltransferases (PRMTs) modify diverse protein targets and regulate numerous cellular processes; yet, their contributions to individual effector T cell responses during infections are incompletely understood. In this study, we identify PRMT5 as a critical regulator of CD4+ T follicular helper cell (Tfh) responses during influenza virus infection in mice. Conditional PRMT5 deletion in murine T cells results in an almost complete ablation of both Tfh and T follicular regulatory populations and, consequently, reduced B cell activation and influenza-specific Ab production. Supporting a potential mechanism, we observe elevated surface expression of IL-2Rα on non-T regulatory effector PRMT5-deficient T cells. Notably, IL-2 signaling is known to negatively impact Tfh differentiation. Collectively, our findings identify PRMT5 as a prominent regulator of Tfh programming, with potential causal links to IL-2 signaling.

Zeb2 drives the formation of CD11c+ atypical B cells to sustain germinal centers that control persistent infection.

CD11c+ atypical B cells (ABCs) are an alternative memory B cell lineage associated with immunization, infection, and autoimmunity. However, the factors that drive the transcriptional program of ABCs have not been identified, and the function of this population remains incompletely understood. Here, we identified candidate transcription factors associated with the ABC population based on a human tonsillar B cell single-cell dataset. We identified CD11c+ B cells in mice with a similar transcriptomic signature to human ABCs, and using an optimized CRISPR-Cas9 knockdown screen, we observed that loss of zinc finger E-box binding homeobox 2 (Zeb2) impaired ABC formation. Furthermore, ZEB2 haplo-insufficient Mowat-Wilson syndrome (MWS) patients have decreased circulating ABCs in the blood. In Cd23Cre/+Zeb2fl/fl mice with impaired ABC formation, ABCs were dispensable for efficient humoral responses after Plasmodium sporozoite immunization but were required to control recrudescent blood-stage malaria. Immune phenotyping revealed that ABCs drive optimal T follicular helper (TFH) cell formation and germinal center (GC) responses and they reside at the red/white pulp border, likely permitting better access to pathogen antigens for presentation. Collectively, our study shows that ABC formation is dependent on Zeb2, and these cells can limit recrudescent infection by sustaining GC reactions.

Eosinophils restrain humoral alloimmunity after lung transplantation.

While the function of many leukocytes in transplant biology has been well defined, the role of eosinophils is controversial and remains poorly explored. Conflicting data exist regarding eosinophils' role in alloimmunity. Due to their prevalence in the lung, and their defined role in other pulmonary pathologies such as asthma, we set out to explore the role of eosinophils in the long-term maintenance of the lung allograft. We noted that depletion of eosinophils results in the generation of donor-specific antibodies. Eosinophil depletion increased memory B cell, plasma cell, and antibody-secreting cell differentiation and resulted in de novo generation of follicular germinal centers. Germinal center formation depended on the expansion of CD4+Foxp3-Bcl6+CXCR5+PD-1+ T follicular helper (Tfh) cells, which increase in number after eosinophil depletion. Mechanistically, we demonstrate that eosinophils prevent Tfh cell generation by acting as the dominant source of IFN-γ in an established lung allograft, thus facilitating Th1 rather than Tfh polarization of naive CD4+ T cells. Our data thus describe what we believe is a unique and previously unknown role for eosinophils in maintaining allograft tolerance and suggest that indiscriminate administration of eosinophil-lytic corticosteroids for treatment of acute cellular rejection may inadvertently promote humoral alloimmunity.

Mitochondrial Pyruvate Carrier Inhibition Mitigates Murine Chronic Graft Versus Host Disease By Attenuating the Germinal Center Reaction

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potent therapy for many hematopoietic diseases and malignancies. However, the long-term efficacy of allo-HSCT is limited by the development of chronic graft versus host disease (cGVHD). During cGVHD, interactions between donor-derived T follicular helper cells (TFH) and germinal center B cells (GCB) result in the production of alloreactive class-switched affinity-matured antibodies that attack host tissues, causing multi-organ damage and tissue fibrosis. Novel treatment approaches are warranted to treat cGVHD since it is often refractory to current broad immune suppressive drugs. In this study we sought to delineate the metabolic dependencies of germinal center (GC) immune cells to discover new strategies to treat active murine cGVHD. We utilized a multi-organ mouse model of cGVHD that includes bronchiolitis obliterans (BO), a severe cGVHD manifestation seen in the clinic. Toward that end, B10.BR (H2 k) recipients received myeloablative conditioning with cyclophosphamide and total body irradiation before receiving MHC mismatched C57BL/6 (H2 b) donor T cell depleted bone marrow with (cGVHD) or without (BM only control) a low dose of splenic T cells. First, we sought to assess the metabolic dependencies of TFH during cGVHD progression through Seahorse metabolic flux assays. TFH sorted early (D28) from cGVHD mice were highly glycolytic with an increased extracellular acidification rate (ECAR) and less reliant on oxidative phosphorylation (OXPHOS) as reflected by a decreased oxygen consumption rate (OCR). However, TFH sorted later (D49) from cGVHD mice demonstrated a dramatic shift in their metabolic profile to a decreased ECAR and an increased OCR indicating a transition from glycolysis towards OXPHOS as disease progresses. To understand which substrates are driving increased OXPHOS and to identify promising metabolic targets, we performed unbiased metabolomics of sort purified TFH from BM only and cGVHD mice on D49 post-transplantation (Fig A). Among the top fifty differential metabolites, cGVHD TFH had a decreased abundance of anaplerotic amino acids (serine, glutamine) and an increased abundance of multiple breakdown products of anaplerotic amino acids (tryptophan, leucine), indicative of increased replenishment of tricarboxylic acid (TCA) cycle intermediates. Notably these metabolomics data showed a decreased abundance of glutamine which is consistent with an increase in glutaminolysis, validating our prior findings that TFH cells that cause cGVHD/BO depend on glutaminolysis ( Johnson MO, Cell 2018). Additionally, there was an increased abundance of pyruvate, which can be transported into mitochondria to fuel the TCA cycle through the mitochondrial pyruvate carrier (MPC). Based on these findings we chose to target the MPC since it has a central role in tying pyruvate to the TCA cycle and OXPHOS. We assessed the effect of an MPC inhibitor (7ACC1) on the GC reaction utilizing an ex vivo co-culture assay of TFH and B cells. 7ACC1 added to this co-culture system resulted in a significant reduction in the production of class-switched immunoglobulin compared to vehicle treatment. To assess the in vivo efficacy, we administered 7ACC1 daily through intraperitoneal injections after establishment of cGVHD (Days 28-49) in the cGVHD/BO mouse model. 7ACC1 treatment resulted in a significant reduction of the GC reaction with significantly decreased TFH and GCB frequencies. Additionally, there was a significant improvement in cGVHD disease severity as evidenced by assessing pulmonary function tests in anesthetized, intubated and mechanically ventilated mice using plethysmography. In contrast to the high resistance and low compliance seen in cGVHD/BO mice, 7ACC1 treated recipients had significantly improved lung function, comparable to the BM only controls (Fig B). In summary, inhibiting MPC mediated transport of pyruvate represents a novel approach to stifling the metabolic demands of TFH as their energy dependency shifts from glycolysis towards OXPHOS during the course of cGVHD/BO disease progression.

Clinical pathological characteristics analysis of ocular adnexal follicular lymphoma

Objective: To investigate the clinical pathological characteristics of ocular adnexal follicular lymphoma (OAFL). Methods: A retrospective case series study was conducted. Clinical data of 10 OAFL patients diagnosed at Tianjin Eye Hospital from January 1990 to May 2022 were collected. The study analyzed general patient information, medical history, site of involvement, imaging, histopathology, and molecular detection. Among them, 7 cases underwent Epstein-Barr virus-encoded small RNA (EBER) and B-cell lymphoma protein 2 (BCL-2)/immunoglobulin heavy chain gene (IgH) translocation gene detection. Treatment and prognosis of patients were followed up. Results: All 10 patients (10 eyes) had unilateral involvement, including 5 males and 5 females, with an age range of 58 (43, 68) years. Clinical manifestations included eyelid swelling, pink conjunctival thickening, painless slow-growing masses in the lacrimal gland area, extraconal muscle cone, conjunctiva, lacrimal sac, or a combination of lacrimal sac and conjunctiva. Among them, 8 cases were primary, and 2 cases were secondary. According to the Ann Arbor staging, 8 cases were stage Ⅰ-Ⅱ E, and 2 cases were stage Ⅲ E. Histopathological grading revealed 6 cases of grade 1-2 and 3 cases of grade 3A. One case showed grade 3B in the lacrimal sac area and grade 1-2 in the conjunctiva. The predominant subtype was follicular in 4 cases, diffuse in 3 cases, and mixed in 2 cases. One case had a mixed subtype involving the lacrimal sac and conjunctiva. All patients expressed positivity for leukocyte differentiation antigens (CD) 20, CD21, and CD23. Nine cases were positive for CD10, with 1 case showing partial CD10 positivity. All patients were positive for B-cell lymphoma protein 6 (BCL-6), and 9 cases were positive for BCL-2. Specific markers CyclinD1 and Multiple Myeloma Oncogene Protein 1 (MUM-1) were negatively expressed in all cases. The Ki-67 proliferation index ranged from 10% to 90%. Molecular detection was performed in 7 patients, with none showing positive EBER in situ hybridization. However, 5 cases exhibited BCL2/IgH gene fusion. Among 7 patients with follow-up data, the median follow-up time was 17 (6, 34) months. Four patients achieved complete remission, 2 had partial remission, and 1 patient died due to lung infection. Conclusions: OAFL is a tumor originating from follicular center B-cells, characterized by positive expression of BCL-2, CD10, and BCL-6. It can involve the lacrimal gland, extraconal muscles, lacrimal sac, and conjunctiva. Patients generally have a favorable prognosis.

Intranasal boosting with RBD-HR protein vaccine elicits robust mucosal and systemic immune responses

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has decreased the efficacy of SARS-CoV-2 vaccines in containing coronavirus disease 2019 (COVID-19) over time, and booster vaccination strategies are urgently necessitated to achieve sufficient protection. Intranasal immunization can improve mucosal immunity, offering protection against the infection and sustaining the spread of SARS-CoV-2. In this study, an intranasal booster of the RBD-HR vaccine after two doses of the mRNA vaccine significantly increased the levels of specific binding antibodies in serum, nasal lavage fluid, and bronchoalveolar lavage fluid compared with only two doses of mRNA vaccine. After intranasal boosting with the RBD-HR vaccine, the levels of serum neutralizing antibodies against prototype and variant strains of SARS-CoV-2 pseudoviruses were markedly higher than those in mice receiving mRNA vaccine alone, and intranasal boosting with the RBD-HR vaccine also inhibited the binding of RBD to hACE2 receptors. Furthermore, the heterologous intranasal immunization regimen promoted extensive memory T cell responses and activated CD103+ dendritic cells in the respiratory mucosa, and potently enhanced the formation of T follicular helper cells and germinal center B cells in vital immune organs, including mediastinal lymph nodes, inguinal lymph nodes, and spleen. Collectively, these data infer that heterologous intranasal boosting with the RBD-HR vaccine elicited broad protective immunity against SARS-CoV-2 both locally and systemically.

Deficiency of germinal center kinase TRAF2 and NCK-interacting kinase (TNIK) in B cells does not affect atherosclerosis.

Atherosclerosis is the underlying cause of many cardiovascular diseases, such as myocardial infarction or stroke. B cells, and their production of pro- and anti-atherogenic antibodies, play an important role in atherosclerosis. In B cells, TRAF2 and NCK-interacting Kinase (TNIK), a germinal center kinase, was shown to bind to TNF-receptor associated factor 6 (TRAF6), and to be involved in JNK and NF-κB signaling in human B cells, a pathway associated with antibody production. We here investigate the role of TNIK-deficient B cells in atherosclerosis. ApoE-/-TNIKfl/fl (TNIKBWT) and ApoE-/-TNIKfl/flCD19-cre (TNIKBKO) mice received a high cholesterol diet for 10 weeks. Atherosclerotic plaque area did not differ between TNIKBKO and TNIKBWT mice, nor was there any difference in plaque necrotic core, macrophage, T cell, α-SMA and collagen content. B1 and B2 cell numbers did not change in TNIKBKO mice, and marginal zone, follicular or germinal center B cells were unaffected. Total IgM and IgG levels, as well as oxidation specific epitope (OSE) IgM and IgG levels, did not change in absence of B cell TNIK. In contrast, plasma IgA levels were decreased in TNIKBKO mice, whereas the number of IgA+ B cells in intestinal Peyer's patches increased. No effects could be detected on T cell or myeloid cell numbers or subsets. We here conclude that in hyperlipidemic ApoE-/- mice, B cell specific TNIK deficiency does not affect atherosclerosis.

A-910823, a squalene-based emulsion adjuvant, induces T follicular helper cells and humoral immune responses via α-tocopherol component.

Adjuvants are chemical or biological materials that enhance the efficacy of vaccines. A-910823 is a squalene-based emulsion adjuvant used for S-268019-b, a novel vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is currently in clinical development. Published evidence has demonstrated that A-910823 can enhance the induction of neutralizing antibodies against SARS-CoV-2 in humans and animal models. However, the characteristics and mechanisms of the immune responses induced by A-910823 are not yet known. To characterize A-910823, we compared the adaptive immune response profile enhanced by A-910823 with that of other adjuvants (AddaVax, QS21, aluminum salt-based adjuvants, and empty lipid nanoparticle [eLNP]) in a murine model. Compared with other adjuvants, A-910823 enhanced humoral immune responses to an equal or greater extent following potent T follicular helper (Tfh) and germinal center B (GCB) cell induction, without inducing a strong systemic inflammatory cytokine response. Furthermore, S-268019-b containing A-910823 adjuvant produced similar results even when given as a booster dose following primary administration of a lipid nanoparticle-encapsulated messenger RNA (mRNA-LNP) vaccine. Preparation of modified A-910823 adjuvants to identify which components of A-910823 play a role in driving the adjuvant effect and detailed evaluation of the immunological characteristics induced by each adjuvant showed that the induction of humoral immunity and Tfh and GCB cell induction in A-910823 were dependent on α-tocopherol. Finally, we revealed that the recruitment of inflammatory cells to the draining lymph nodes and induction of serum cytokines and chemokines by A-910823 were also dependent on the α-tocopherol component. This study demonstrates that the novel adjuvant A-910823 is capable of robust Tfh cell induction and humoral immune responses, even when given as a booster dose. The findings also emphasize that α-tocopherol drives the potent Tfh-inducing adjuvant function of A-910823. Overall, our data provide key information that may inform the future production of improved adjuvants.

Stimulation of B-Lymphopoiesis by Administration of a Trimecaine-Based Ionic Compound in Cyclophosphamide-Induced Hematopoietic-Depressive Model.

According to the WHO, the secondary form of hematopoietic-depressive status increases the risk of death in people with oncological, infectious, and hormonal diseases. The choice of drugs that stimulate the hematopoietic activity of B-lymphopoiesis is limited. The current leucopoiesis drugs have a number of side effects: thymic preparations stimulate the production of PGE2, which causes chronic inflammation and various autoimmune diseases through the differentiation of T helper 1 (Th1) cells, the proliferation of Th17 cells, and the production of IL-22 from Th22 cells through EP2 and EP4 receptors; cytokine preparations can cause uncontrolled immune reactions and impaired contractility of smooth and cardiac muscles; drugs based on nucleic acids can stimulate the division of all cells, including bacterial and cancerous ones. The use of oligonucleotides such as ribozymes and antisense oligodeoxynucleotides (AS-ODNs) shows promise as therapeutic moieties, but faces a number of challenges such as nuclease sensitivity, off-target effects, and efficient delivery. The search for substances that stimulate B-lymphopoiesis among ionic compounds was motivated by the discovery of the unique properties of lidocaine docusate, one of the first ionic liquid forms of the known drugs. The lidocaine docusate (protonated form of lidocaine (2-(diethylamino)-N-(2,6-dimethylphenyl) acetamide + docusate-anion (dioctylsulfosuccinate))) suppresses the division of pheochromocytoma cells and activates immunity in rats. The trimecaine-based ionic compound (TIC) demonstrates high B-lymphopoiesis-stimulating activity. The TIC compound stimulates an increase in the volume of transitional B cells, which play an important role for further differentiation and formation of a sufficient number of mature B1 cells and mature B2 cells, where mature B2 cells make up the bulk of the functional population of B lymphocytes. The TIC compound most strongly stimulated the restoration of the number of marginal zone B cells, follicular B cells, and activated germinal center B cells after the cytotoxic emptying of the follicular centers of the spleen induced cyclophosphamide. It significantly exceeds the activity of the comparison drug methyluracil. The TIC compound does not affect the level of pro-B, pre-B-I, or pre-B-II bone marrow cells, which prevents the risk of the formation of immature functionally defective cells.

The HDAC inhibitor zabadinostat is a systemic regulator of adaptive immunity

Protein acetylation plays a key role in regulating cellular processes and is subject to aberrant control in diverse pathologies. Although histone deacetylase (HDAC) inhibitors are approved drugs for certain cancers, it is not known whether they can be deployed in other therapeutic contexts. We have explored the clinical HDAC inhibitor, zabadinostat/CXD101, and found that it is a stand-alone regulator of the adaptive immune response. Zabadinostat treatment increased expression of MHC class I and II genes in a variety of cells, including dendritic cells (DCs) and healthy tissue. Remarkably, zabadinostat enhanced the activity of DCs, and CD4 and CD8 T lymphocytes. Using an antigenic peptide presented to the immune system by MHC class I, zabadinostat caused an increase in antigen-specific CD8 T lymphocytes. Further, mice immunised with covid19 spike protein and treated with zabadinostat exhibit enhanced covid19 neutralising antibodies and an increased level of T lymphocytes. The enhanced humoral response reflected increased activity of T follicular helper (Tfh) cells and germinal centre (GC) B cells. Our results argue strongly that zabadinostat has potential to augment diverse therapeutic agents that act through the immune system.

Composite Lymphoma Comprising Follicular Lymphoma with In-situ Mantle Cell Neoplasia: A Case Report and Review of the Literature

A 55-year-old gentleman presented to our hospital with a single inguinal adenopathy, and no other clinical symptoms or signs. An excisional lymph node biopsy was performed. Pathologic evaluation demonstrated follicular center site which stained positive for CD20, CD10, Bcl-2, Bcl-6, and mantle zone cells which demonstrated Cyclin D1 (CCND1) positivity, partial SOX11 positivity and no expression of CD5, suggesting the diagnosis of composite lymphoma comprising follicular lymphoma (FL) with in situ mantle cell neoplasia (ISMCN), the latter previously referred as in situ mantle cell lymphoma (MCLIS). FL is known as indolent non-Hodgkin lymphoma; however, the clinical significance of a coexisting ISMCN continues to be elusive, and optimal management of these patients remains largely unknown. This paper reports a new case of this extremely uncommon condition and also discusses reviews of the literature including advances in molecular pathogenesis and lymphoma genomics with the aim to offer novel insights into this rare hematological malignancy.

Boosting B Cell and Macrophage-Mediated Humoral Immunity with Fusion Nanovesicles for Triple-Negative Breast Cancer Combined Therapy.

Cell-derived nanovesicles are widely utilized as therapeutic agents for cancer therapy. Current research mostly focuses on their ability to activate antitumor cellular immunity. However, whether they can activate and participate in antitumor humoral immunity is rarely studied. Here, doxorubicin-loaded hybrid cell nanovesicles (DNVs) are designed for boosting antitumor humoral and cellular immunity. The hybrid cell nanovesicles are generated through fusion of nanovesicles derived from M1-type macrophages and 4T1 tumor cells. It is found that DNVs can accumulate at tumor tissues and draining lymph nodes effectively, which results in the activation of antitumor immune response and significant inhibition of tumor progression. During this process, dendritic cells are effectively activated, subsequently inducing cytotoxicity T lymphocytes-mediated cellular immunity. Furthermore, DNVs elicit the antitumor humoral immunity through boosting T follicular helper cells and germinal center B cells. By analyzing the mechanism behind humoral immunity activation, it is found that M1-type macrophages repolarized by DNVs play an important role. In general, besides antitumor cellular immunity, the proposed hybrid nanovesicles provide a promising strategy for enhancing antitumor humoral immunity by macrophages repolarization and germinal center B cells activation.

ODP510 Pseudolymphoma of the Thyroid Gland in Association with Hashimoto's Thyroiditis: A Benign Lesion in Whitish Thyroid Gland

Abstract Background Pseudolymphoma or reactive lymphoid hyperplasia is a benign localized tumor-forming lymphoid hyperplasia found in various organs. Its occurrence in the thyroid gland is rare and could mimic malignant lesion. Here, we present a case of pseudolymphoma of the thyroid in a patient with Hashimoto's Thyroiditis. Case description A 24-year-old woman without underlying disease presented with incidentally found thyroid nodule. Ultrasound revealed mild thyroid enlargement with diffuse heterogeneous parenchymal echotexture. A 5×7×8.5-mm hypoechoic solid nodule with irregular margin was found in the left upper pole. No microcalcification was detected. Multiple subcentimeter lymph nodes at bilateral cervical group VI and left cervical group IV were also detected, measuring up to 5 mm in short axis. Fine-needle aspiration was performed and suggested malignancy (Bethesda class V). Laboratory testing showed euthyroid state with positive anti-thyroglobulin antibodies and anti-thyroid peroxidase antibodies. The blood test and ultrasound findings suggested the underlying of Hashimoto's thyroiditis. The patient underwent total thyroidectomy and lymph node dissection without postoperative complication. Gross examination of the thyroid showed multiple well-demarcated whitish nodular lesions, ranging from 2-10 mm, in the upper pole of both thyroid lobe and a well-circumscribed area of a 7-mm greyish nodule in left thyroid lobe. Microscopically, the whitish lesion in both lobe composed of hyperplastic lymphoid tissues with many follicular centers on the background of lymphocytic thyroiditis. The immunohistochemistry study revealed a polyclonal nature of the plasma cell infiltrates. No abnormal staining with AE1/AE3 or cyclin D1 was found. Pseudolymphoma was diagnosed based on these findings. Papillary thyroid microcarcinoma (6 mm) without capsular invasion was also diagnosed in the lesion of left mid lobe. The cervical lymph nodes showed metastatic papillary thyroid carcinoma (1.5 mm) in level III cervical lymph nodes. No perinodal extension was found. Postoperative course was unremarkable and the patient was in stable condition at 18 months after the operation. Conclusion Although primary thyroid lymphoma is often considered in patients with Hashimoto's thyroiditis. The possibility of pseudolymphoma characterized by the presence of well-demarcated pearly white nodules and polyclonal cell populations should also be considered. Presentation: No date and time listed

The magnitude of the germinal center B cell and T follicular helper cell response predicts long-lasting antibody titers to plague vaccination.

The development of a safe and effective vaccine against Yersinia pestis, the causative organism for plague disease, remains an important global health priority. Studies have demonstrated effective immune-based protection against plague challenge that is induced by plague antigen subunit vaccination in an aqueous alhydrogel formulation; however, whether these candidate vaccines in this formulation and presentation, induce long-lasting immunological memory in the form of durable cellular and antibody recall responses has not been fully demonstrated. In this study, we analyzed germinal center T follicular helper and germinal center B cell responses following F1V and F1 + V plague subunit immunization of mice with vaccines formulated in various adjuvants. Our data demonstrate that recombinant plague protein immunization formulated with IL-2/GM-CSF cytokines bound to alhydrogel adjuvant drive an increase in the magnitude of the germinal center T follicular helper and germinal center B cell responses following primary immunization, compared to vaccines formulated with Alhydrogel adjuvant alone. In contrast, plague protein subunit immunization combined with CpG ODN bound to alhydrogel increased the magnitude and duration of the germinal center Tfh and B cell responses following booster immunization. Importantly, enhanced germinal center Tfh and B cell responses correlated with long-lasting and high F1V-specific antibody titers and more robust antibody recall responses to F1V re-exposure. These findings indicate that vaccine formulations that drive enhancement of the germinal center Tfh and B cell responses are critical for inducing durable plague-specific humoral immunity.