Mouse Spleen Cells Research Articles

Short-chain fatty acid butyrate induces IL-10-producing B cells by regulating circadian-clock-related genes to ameliorate Sjögren's syndrome.

Sjögren's syndrome (SS) is an autoimmune disease caused by inflammation of the exocrine gland. The pathological hallmark of SS is the infiltration of lymphocytes into the salivary glands. Increased infiltration of T and B cells into salivary glands exacerbates symptoms of SS. Several recent studies have identified the role of gut microbiota in SS. Butyrate, one of the metabolites of the gut microbiota, regulates T cells; however, its effects on B cells and SS remain unknown. This study determined the therapeutic effect of butyrate on regulating B cells in SS. Various concentrations of butyrate were intraperitoneally injected three times per week in NOD/ShiLtJ (NOD) mice, the prototype animal model for SS, and observed for more than 10 weeks. Whole salivary flow rate and the histopathology of salivary glands were investigated. Human submandibular gland (HSG) cells and B cells in mouse spleen were used to confirm the anti-inflammatory and immunomodulatory effects of butyrate. Butyrate increased salivary flow rate in NOD mice and reduced inflammation of salivary gland tissues. It also regulated cell death and the expression of circadian-clock-related genes in HSG cells. Butyrate induced B cell regulation by increasing IL-10-producing B (B10) cells and decreasing IL-17-producing B cells, through the circadian clock genes RAR-related orphan receptor alpha and nuclear receptor subfamily 1 group D member 1. The findings of this study imply that butyrate may ameliorate SS via reciprocal regulation of IL-10- and IL-17-producing B cells.

The role of regulatory B cells in Echinococcus granulosus-infected mice.

To investigate the phenotypic changes of the expression level of regulatory B cells and related molecules during the continuous infection of Echinococcus granulosus (E. granulosus) in mice and its relationship with E. granulosus infection and its immune effect. Experimental group mice were inoculated with protoscoleces suspension via intraperitoneally injection to prepare a mouse model of E. granulosus infection. Flow cytometry was used to detect the expression of regulatory B cells CD1dhiCD5+CD19hi cells and CD1dhiCD5+CD19hi IL-10+ cells in spleen and peripheral blood of mice. The expressions of IL-10 and TGF-β1 in mouse serum were detected via ELISA. The liver pathological changes in mice were observed by H&E staining; Moreover, the expressions and distribution of IL-10 and TGF-β1 in mice liver were measured through immunohistochemistry. The ELISA test results showed no significant changes in serum IL-10 and TGF-β1 levels in early infected mice. However, at the middle and late stages of infection, the levels of IL-10 and TGF-β1 in the serum of mice increased significantly (P < 0.05). The proportion of CD1dhiCD5+CD19hiBreg cells and the proportion of CD1dhiCD5+CD19hiIL-10+Breg cells in the spleen of mice infected with E. granulosus were increased at 90days after infection, which indicating that Breg cells proliferated in the late stage of infection. CD1dhiCD5+CD19hi regulatory B cells may be one of the causes of immunosuppression of E. granulosus infection. It is speculated that Bregs inhibitory effect may play a role by regulating the expression of cytokines and inducing the secretion of inhibitory cytokines IL-10 and TGF-β1.

Characterization of glycoprotein IIb/IIIa-specific alloantibodies induced by cross-strain platelet immunization in mice.

We previously described a mouse model in which platelet immunization between selected strains leads to production of alloantibodies and severe autoimmune thrombocytopenia and mimics the human condition posttransfusion purpura (PTP). This report describes studies defining epitopes recognized by these alloantibodies. Hybridomas were produced from spleen cells of immunized mice. Glycoprotein (GP) targets of resulting monoclonal antibodies were characterized by immunoprecipitation using platelets from the immunizing strains. Antigens defined by single amino acid (AA) polymorphisms recognized by monoclonal antibodies were identified by mutagenizing target glycoproteins expressed in Chinese hamster ovary cells and observing the effects on antibody binding. Three monoclonal antibodies (417.1, 417.3, 425.1) were produced that recognized GPIIb on immunizing platelets. Monoclonal antibodies 417.1 and 417.3 both required G111 and 425.1 required V37, located on the beta propeller domain of GPIIb, for binding to platelets from the immunizing strains C57 and PWK, respectively. Injection of 417.3 and 425.1 into mice caused platelet destruction only in mice with GPIIb containing the targeted AAs. Findings made provide evidence that alloantibodies produced by mice experiencing thrombocytopenia in a mouse model of PTP are specific for single AA polymorphisms that differ in GPIIb/IIIa integrin of the immunizing and immunized strains and therefore closely resemble the potent alloantibodies found in patients with PTP. The observations show that naturally occurring single AA differences in GPIIb/IIIa integrin of various mouse strains are highly immunogenic in the mouse strains studied and readily induce antibodies comparable to human platelet antigen-specific antibodies found in transfused and pregnant humans.

Characterization of Treponema pallidum Dissemination in C57BL/6 Mice.

The spirochetal pathogen Treponema pallidum causes 5 million new cases of venereal syphilis worldwide each year. One major obstacle to syphilis prevention and treatment is the lack of suitable experimental animal models to study its pathogenesis. Accordingly, in this study, we further evaluated the responses of mice to Treponema pallidum. Quantitative polymerase chain reaction showed that Treponema pallidum could colonize the heart, liver, spleen, kidneys, and testicles of C57BL/6 mice, and the organism may be able to rapidly penetrate the blood-brain barrier in mice by 24 h after infection. In subsequent rabbit infectivity tests, we observed evident signs of the microorganism in the mouse lymph node suspension. After infection, bacterial loads were higher in the tissues than in the blood of C57BL/6 mice. Moreover, a significant Th1 immune response was recorded by cytokine assays. Flow cytometric analysis suggested an obvious increase in the proportion of CD3+ T and CD4+ T cells in the spleen cells in the infected mice. Thus, improving our understanding of the response of C57BL/6 mice for Treponema pallidum will help to comprehensive elucidate the pathogenic mechanisms of this bacterium and lay the foundation for the development of a new research model of Treponema pallidum.

ILT4 inhibition prevents TAM- and dysfunctional T cell-mediated immunosuppression and enhances the efficacy of anti-PD-L1 therapy in NSCLC with EGFR activation.

Rationale: Immune checkpoint inhibitors (ICIs) against the PD-1/PD-L1 pathway showed limited success in non-small cell lung cancer (NSCLC) patients, especially in those with activating epidermal growth factor receptor (EGFR) mutations. Elucidation of the mechanisms underlying EGFR-mediated tumor immune escape and the development of effective immune therapeutics are urgently needed. Immunoglobulin-like transcript (ILT) 4, a crucial immunosuppressive molecule initially identified in myeloid cells, is enriched in solid tumor cells and promotes the malignant behavior of NSCLC. However, the upstream regulation of ILT4 overexpression and its function in tumor immunity of NSCLC with EGFR activation remains unclear.Methods: ILT4 expression and EGFR phosphorylation in human NSCLC tissues and cell lines were analyzed using immunohistochemistry (IHC), real-time PCR, Western blotting, immunofluorescence, and flow cytometry. The molecular signaling for EGFR-regulated ILT4 expression was investigated using mRNA microarray and The Cancer Genome Atlas (TCGA) database analyses and then confirmed by Western blotting. The regulation of tumor cell proliferation and apoptosis by ILT4 was examined by CCK8 proliferation and apoptosis assays. The impact of ILT4 and PD-L1 on tumor-associated macrophage (TAM) recruitment and polarization was evaluated using Transwell migration assay, flow cytometry, enzyme linked immunosorbent assay (ELISA) and real-time PCR, while their impact on T cell survival and cytotoxicity was analyzed by CFSE proliferation assay, apoptotic assay, flow cytometry, ELISA and cytolytic assay. Tumor immunotherapy models targeting at paired Ig-like receptor B (PIR-B, an ortholog of ILT4 in mouse)/ILT4 and/or PD-L1 were established in C57BL/6 mice inoculated with stable EGFR- overexpressing Lewis lung carcinoma (LLC) cells and in humanized NSG mice inoculated with EGFR mutant, gefitinib-resistant PC9 (PC9-GR) or EGFR-overexpressing wild type H1299 cells. PIR-B and ILT4 inhibition was implemented by infection of specific knockdown lentivirus and PD-L1 was blocked using human/mouse neutralizing antibodies. The tumor growth model was established in NSG mice injected with PIR-B-downregulated LLC cells to evaluate the effect of PIR-B on tumor proliferation. The frequencies and phenotypes of macrophages and T cells in mouse spleens and blood were detected by flow cytometry while those in tumor tissues were determined by IHC and immunofluorescence.Results: We found that ILT4 expression in tumor cells was positively correlated with EGFR phosphorylation in human NSCLC tissues. Using NSCLC cell lines, we demonstrated that ILT4 was upregulated by both tyrosine kinase mutation-induced and epidermal growth factor (EGF)-dependent EGFR activation and subsequent AKT/ERK1/2 phosphorylation. Overexpressed ILT4 in EGFR-activated tumor cells induced TAM recruitment and M2-like polarization, which impaired T cell function. ILT4 also directly inhibited T cell proliferation, cytotoxicity, and IFN-γ expression and secretion. In EGFR-activated cell lines in vitro and in wild-type EGFR-activated C57BL/6 and humanized NSG immunotherapy models in vivo, either ILT4 (PIR-B) or PD-L1 inhibition enhanced anti-tumor immunity and suppressed tumor progression by counteracting TAM- and dysfunctional T cell- induced immuno-suppressive TME; the combined inhibition of both molecules showed the most dramatic tumor retraction. Surprisingly, in EGFR mutant, TKI resistant humanized NSG immunotherapy model, ILT4 inhibition alone rather than in combination with a PD-L1 inhibitor suppressed tumor growth and immune evasion.Conclusions: ILT4 was induced by activation of EGFR-AKT and ERK1/2 signaling in NSCLC cells. Overexpressed ILT4 suppressed tumor immunity by recruiting M2-like TAMs and impairing T cell response, while ILT4 inhibition prevented immunosuppression and tumor promotion. Furthermore, ILT4 inhibition enhanced the efficacy of PD-L1 inhibitor in EGFR wild-type but not in EGFR mutant NSCLC. Our study identified novel mechanisms for EGFR-mediated tumor immune escape, and provided promising immunotherapeutic strategies for patients with EGFR-activated NSCLC.

Recognition of acrolein-specific epitopes by B cell receptors triggers an innate immune response

Natural antibodies, predominantly immunoglobulin M (IgM), play an important role in the defense against pathogens and in maintaining homeostasis against oxidized molecules known as oxidation-specific epitopes, such as those contained in oxidized low-density lipoproteins. However, owing to the complexity of the oxidized products, very few individual epitopes have been characterized in detail. In the present study, to identify endogenous sources of oxidation-specific epitopes, we stimulated mouse spleen and peritoneal cavity (PerC) cells in vitro with bovine serum albumin modified with a variety of lipid peroxidation–related carbonyl compounds and identified the acrolein-modified bovine serum albumin as the most efficient trigger studied for the production of IgM in PerC cells. The acrolein-specific epitopes accelerated the differentiation of B-1a cells, a fetal-derived B cell lineage, to plasma cells. In addition, acrolein-modified bovine serum albumin was specifically bound to B-1a cells, suggesting the presence of an acrolein-specific IgM–B cell receptor (BCR). A hybridoma, RE-G25, producing an acrolein-specific IgM, was established from the PerC cells and was indeed identified as a population of B cells expressing a specific IgM–BCR. In addition, we analyzed the BCR repertoire of acrolein-specific B cells and identified the most frequent IgM heavy chain gene segments of the B cells. These data established the presence of innate B cells expressing the acrolein-specific BCR and suggested that in addition to our understanding of acrolein as a toxic aldehyde, it may play a role as a trigger of the innate immune response.

Stimulatory effect of Holy basil and Thai basil on mouse spleen cell proliferation

ABSTRACT Study was conducted on mouse spleen cells, cultured and incubated in-vitro with Holy basil and Thai basil, to observe their effect on proliferation. Four dilutions, namely 1:1, 1:5, 1:25, and 1:125, for both Holy basil and Thai Basil were used separately, in presence and absence of mitogen, Concanavalin A (Con A) to stimulate the T cells. Cell proliferation was monitored by 3 H- thymidine radioisotope incorporation. Spleen cells (macrophages, B and T cells) showed significantly more proliferation at 1:1 dilution than control (cells with no factor), incubated with Holy basil (in assay without Con A). Spleen T cells, however, did not show any significance in proliferation at same dilution, 1:1, with Holy basil with Con A. All other dilutions (with or without Con A), for either Holy basil or Thai basil, did not show any significant changes in proliferation when compared to control.

Chlorogenic acid induces apoptosis, inhibits metastasis and improves antitumor immunity in breast cancer via the NF‑κB signaling pathway.

Breast cancer which is the most common type of diagnosed cancer among women worldwide possesses metastatic potential, multi-drug resistance, and high mortality. The NF-κB signaling pathway has been revealed to be abnormally activated in breast cancer cells and closely associated with high metastasis and poor prognosis. In the present study, it was reported that chlorogenic acid (CGA), a potent NF-κB inhibitor derived from coffee, exerted antitumor activity in breast cancer. MTT and colony formation assays were conducted and it was revealed that CGA inhibited viability and proliferation in breast cancer cells. Additionally, CGA significantly induced apoptosis and suppressed migration and invasion in breast cancer cells. Notably, immunofluorescence analysis confirmed that CGA could efficiently suppress nuclear transcription of NF-κB p65. In addition, results of western blotting demonstrated that CGA markedly impaired the NF-κB and EMT signaling pathways. The antitumor effect of CGA was evaluated in a subcutaneous tumor mouse model of 4T1 cells, and the results revealed that CGA markedly retarded tumor growth and prolonged the survival rate of tumor-bearing mice. Notably, CGA inhibited pulmonary metastasis of 4T1 cells by enhancing the proportion of CD4+ and CD8+ T cells in spleens of mice, which indicated an improvement of antitumor immunity. In conclusion, the present present study demonstrated that CGA improved antitumor immunity, exerting antitumor and anti-metastatic effects by impairing the NF-κB/EMT signaling pathway, suggesting that CGA may serve as a potential candidate for therapy of breast cancer.

Antitumor effects and mechanisms of CpG ODN combined with attenuated Salmonella-delivered siRNAs against PD-1

Numerous studies have focused on the treatment of melanoma, but the current therapies for melanoma have limited therapeutic effects. To find a more effective therapy for melanoma, we combined artificially designed CpG ODN (cytosine-phosphate-guanine oligodeoxynucleotides) and siRNAs (small-interfering ribonucleic acids) targeting PD-1 (programmed cell death protein 1), which were delivered by attenuated Salmonella to treat melanoma in mice, and explored the underlying antitumor mechanisms. We found that mice receiving the combination therapy had the smallest tumor size and the longest survival time. The possible mechanisms underlying this phenomenon include pathways mediated by cyclin D1, p-STAT3 (phosphorylated signal transducers and activators of transcription protein 3), MMP2 (matrix metallopeptidase 2) and cleaved caspase 3, since after treatment, the expression of cyclin D1, p-STAT3, and MMP2 decreased but that of cleaved caspase 3 increased; additional mechanisms include increases in the recruitment of immune cells to tumor sites and in the number of immune cells in mouse spleens and the upregulation of TNF-α (tumor necrosis factor) and IL-6 (interleukin 6). We demonstrated that the combination therapy composed of CpG ODN and PD-1-siRNA delivered by attenuated Salmonella exhibited a strong ability to inhibit melanoma and improve the antitumor immune responses of tumor-bearing mice.

Antivirus activity of Xiyanping Injection against Dengue virus serotype 2 in vitro and in vivo

Objective To evaluate the antivirus activity of Xiyanping Injection against Dengue virus serotype 2 (DENV2) in vitro and in vivo. Methods A human hepatoma cell line HepG2 was treated with Xiyanping Injection through different ways, including the direct inactivation of virus, the inhibition of virus entry, administration after virus exposure and combination of pre- and post-exposure administration. The supernatant and cells were harvested in different time point. Then the virus antigen positive cells were detected by indirect immunofluorescence assay (IFA), and the viral RNA was measured by quantitative real-time PCR (qPCR). Moreover, antiviral activity of Xiyanping Injection was further detected with the HepG2 transplanted SCID mice. The mice were intraperitoneally injected with different doses (1,2,4 mg/mouse) of Xiyanping Injection for 4 days following the challenge of DENV2. The organs and sera in different groups were sampled on the sixth day post infection. Then, the numbers of virus antigen positive cells in spleen, liver and sera of mice were detected by IFA, and the survival rate of each group was monitored for 14 days. Results Xiyanping Injection can inactivate DENV2 and inhibit the entry of DENV2 into cells. The replication of DENV2 was significantly inhibited by Xiyanping Injection with the aforementioned medication in a dose-dependent manner. Especially, the antivirus activity of Xiyanping Injection is superior to ribavirin injection in the early and late stage of virus infection. Attractively, Xiyanping can reduce the viral load in organs and sera, and improve the survival rate of experimental mice. Conclusion Xiyanping Injection, as a traditional Chinese herba. displayed obviously antivirus activity and wide safety range in vitro and in vivo . Our results indicate Xiyanping Injection might be a new candidate of antiviral drug for DENV infection. 摘要：目的 分别通过体外和体内实验研究喜炎平注射液对H型登革病毒( Dengue virus serotype 2, DENV2)的抗病 毒作用。 方法 体外实验以利巴韦林注射液作为阳性对照药物, 分别以灭活、抑制进人、治疗性给药以及预防联合维 持治疗的方式处理人肝癌细胞株HepG2细胞, 在不同时相点收获上清和细胞, 分别利用间接免疫荧光(indirect immunofluorescence assay, IFA)和实时荧光定量PCR(quantitative real-time PCR, qPCR)检测DENV2的病毒载量, 从而评价喜炎 平注射液的体外抗DENV2作用。体内实验以SCID小鼠为实验鼠, 腹腔注射HepG2细胞, 建立模型小鼠, 腹腔注射感染 DENV2,次日给予不同剂量(1、2、4mg/只）的喜炎平注射液, 连续给药4d,部分小鼠于感染第6日取材, 利用IFA检测实 验鼠脾、肝及血清中病毒载量, 并观察实验鼠的生存率。 结果 体外实验显示, 喜炎平注射液能够灭活DENV2,并抑制 DENV2进入细胞, 同时无论是治疗还是治疗联合预防给药, 均可对DENV2的复制具有良好的抑制作用, 即在病毒感染 早期及晚期, 喜炎平均可发挥抗病毒作用, 且优于利巴韦林。进一步在体内实验中同样显示喜炎平具有较好的抗病毒 作用, 可以降低实验鼠脾、肝及血清中病毒载量, 并可提高实验鼠的生存率。 结论 喜炎平注射液具有明显的抗 DENV2病毒的作用 , 可为DENV感染的治疗提供新的候选药物

A Murine Immunocompetent Acute Myeloid Leukemia (AML) Model for Testing Immunotherapies

Background With the emergence of immunotherapies as a promising cancer treatment, there is now a pressing need for pre-clinical animal models to test immunotherapy strategies for acute myeloid leukemia (AML). While murine xenotransplant models generated by transplanting human AML cells are frequently used to model AML, they require immune-deficient mice. Syngeneic murine bone marrow transplant leukemia models (MBMTLM), which are established in immune competent mice, usually require radiation of the recipient mouse before leukemic cells are transplanted. This radiation suppresses the immune system and makes it difficult to study how the immune system responds to leukemia cells. Aim Our aim was to establish immunocompetent MBMTLMs to understand how the immune system responds to leukemia cells expressing a highly immunogenic antigen. Method We first established MBMTLMs models driven by the CALM/AF10 or MLL/AF9 fusion genes. Then leukemia cells were transduced with a SIINFEKL expressing retrovirus (MSCV-DsRed-SIINFEKL). SIINFEKL is a highly immunogenic eight amino acid peptide from ovalbumin. Results The transduction efficiency of MSCV-DsRed-SIINFEKL was about 12.9% on leukemic cells of MLL/AF9 and 13% on CALM/AF10 cells. All primary MLL/AF9-SIINFEKL (n=3) developed leukemia with a latency of 22 days. SIINFEKL expression was detected on 75.5±3% of the spleen cells of these mice. These spleen cells were transplanted into irradiated (n=6) and non-irradiated (n=8) mice to establish secondary MLL/AF9-SIINFEKL leukemias (Table 1). In the irradiated recipients, five out of six mice developed leukemia within 22-29 days. In non-irradiated recipients, four out of eight developed leukemia with a latency of 29-45 days. Flow cytometry showed that SIINFEKL was expressed on 82.28±6% of the spleen cells in irradiated recipients. In contrast, fewer than 1% of the spleen cells in non-irradiated mice with secondary MLL/AF9-SIINFEKL leukemia expressed SIINFEKL. Similar experiments were performed with the CALM/AF10 model. All primary CALM/AF10-SIINFEKL transplanted mice (n=2) developed leukemia with a latency of 32 and 42 days and showed SIINFEKL positivity on 99% of the leukemia cells. Secondary CALM/AF10-SIINFEKL leukemias were generated by transplanting these AML cells into irradiated (n=6) and non-irradiated (n=8) mice. All six irradiated recipients developed leukemia within 21-40 days. However, only five of the eight non-irradiated recipients developed leukemia with a latency of 35-42 days. Strikingly, about 99% of the AML cells in the irradiated mice were SIINFEKL positive but fewer than 1% of the AML cells in the five non-irradiated mice who developed leukemia were SIINFEKL positive. Discussion We find that for both MLL/AF9 and CALM/AF10 AML an intact immune system (non-irradiated recipients) is able to largely eliminate AML cells which express the SIINFEKL antigen, even when challenged with a large number of AML cells. In the non-irradiated recipients only 50 to 60% developed leukemia, and the leukemias that did develop had hardly any SIINFEKL-positive cells. In contrast, nearly all irradiated mice (11 of 12) developed leukemia with a high percentage of SIINFEKL expressing AML cells. SIINFEKL was presented on the surface of leukemic cells by the murine MHC class I H-2Kb molecule. Our results differ slightly from research reported by Hasegawa et al. 2015, who showed that MLL/AF9 AML cells expressing ovalbumin caused leukemia after transplantation into non-irradiated mice. However, they did not investigate whether ovalbumin was still being expressed on the leukemia cells. Conclusion We have established syngeneic murine AML models in immunocompetent mice and have evidence that an intact immune system has the ability to suppress or even eliminate rapidly proliferating AML cells if they express a strong antigen. These models should be useful for developing immunotherapy strategies for AML. Disclosures Desai: University of Auckland: Current Employment. Kakadia:University of Auckland: Current Employment. Browett:University of Auckland: Current Employment; BeiGene: Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Shire: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bohlander:University of Auckland: Current Employment; Family of Marijana Kumerich: Research Funding; Leukaemia and Blood Cancer New Zealand: Research Funding.

Evaluation of Immune Function of Mycelium Fermentation of Hirsutella sinensisin In Vitro and In Vivo

In order to confirm whether HSFL (the fermented liquor of mycelia of Hirsutella sinensis) still contains cordycepin, Cordyceps polysaccharide and other functional components, and has the functions of anti-oxidation, tumor inhibition and immunity enhancement, the biological activity of HSFL In Vivo and in vitro was studied in this study. The transformation ability of mouse spleen lymphocytes induced by ConA, the activity of NK cells in mouse spleen, the delayed allergic reaction induced by DNFB and the phagocytosis of chicken red cells by mouse peritoneal macrophages were studied. The results showed that when the concentration of HSFL was 0.5972 mg/kg and 1.1944 mg/kg, the transformation of lymphocytes induced by ConA and the activity of NK cells were significantly increased. HSFL also can significantly improve DNFB induced anaphylaxis in mice and phagocytosis of chicken erythrocytes by peritoneal macrophages in mice when the dose of HSFL is 50 mg/kg and 75 mg/kg, indicating that HSFL has the biological activity of enhancing immunity in vitro and In Vivo.

Immune Function and Mechanism of Costimulating Molecules PD-1 and OX40 in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a T lymphocyte-mediated autoimmune disease, although its immune mechanism has not been fully studied. In this study, healthy controls (HC), osteoarthritis patients (OA), and RA patients were enrolled, and mice were evenly divided into control, collagen-induced arthritis (CIA), PD-1 Fc/CIA (PD-1 Fc membrane fusion protein administered to CIA mice), OX40 Fc/CIA (OX40 Fc membrane fusion protein administered to CIA mice), and PD-1 Fc + OX40 Fc/CIA groups. The expressions of programmed death-1 (PD-1) and OX40 in CD4+ T lymphocytes and the levels of sPD-1, immunoglobulin, and proinflammatory factors in patients and mice were measured. The results showed that the expression levels of PD-1 and OX40 in CD4+ T lymphocytes separated from the peripheral blood and synovial fluid of RA patients and the spleen of CIA mice were observably elevated. The levels of soluble PD-1, interleukin (IL)-2, IL-4, IL-5, IL-17, and interferon-γ (IFN-γ) in RA patients obviously increased. In animal experiments, PD-1 Fc not only increased the serum levels of immunoglobulin G (IgG), IgG1, and IgG2a in CIA mice, but also increased the levels of IL-4, IL-2, IL-5, IL-17, and IFN-γ in mouse spleen cells and joint tissues, which, however, were reversed by OX40 Fc. In conclusion, OX40 inhibition could reverse the progression of RA caused by PD-1 blocking, and PD-1 might be a potential target for RA. Clinical Trials.gov ID: HGH2018012203.

Gu-Ben-Fang-Xiao attenuates allergic airway inflammation by inhibiting BAFF-mediated B cell activation

Allergic airway inflammation is one of the major pathological events involved in the development of asthma. The B cell-activating factor (BAFF)-mediated abnormal activation of B cells plays a key role in developing allergic airway inflammation. Here, we investigated the effects of Gu-Ben-Fang-Xiao decoction (GBFXD), a TCM decoction used in the prevention and treatment of allergic asthma, on allergic airway inflammation and BAFF-mediated B cell activation. A mouse model of OVA-Severe respiratory syncytial virus (RSV) induced asthma in the remission stage was administrated with GBFXD by gavage for four weeks, after which, the pulmonary function was evaluated. Pathological changes of the lung were observed by hematoxylin and eosin (HE) staining, and serum levels of IgE, BAFF, and inflammatory factors were detected by ELISA. The expression of BAFF, APRIL, and their related receptors in the lung and spleen was detected by Western blotting and RT-qPCR. Flow cytometry detected B cell subsets in the spleen, PBC, and monocyte subsets in bronchoalveolar lavage fluid (BALF). The results showed that GBFXD improved the lung function, alleviated the inflammatory changes of the lung tissue in OVA-RSV sensitized mice, and reduced levels of IL-6, TNF-α, IL1-β, INOS, IL13 as well as IL-15, IgE, BAFF in the serum of OVA-RAV mice. Additionally, GBFXD significantly reduced the proportion of CD19+CD27+ B cell subpopulation and IgE + B cell subpopulation in the PBC and spleen cells of mice. Furthermore, the expression of BAFF, APRIL, BAFFR, TACI, and AID decreased in the lung and spleen of GBFXD-treated mice, as well as the proportion of CD11b + BAFF + cell subsets in BALF. In conclusion, GBFXD has an inhibitory effect on the secretion of BAFF by pulmonary macrophages and the expression of BAFF-related receptors, thereby reducing B cell activation and the release of IgE. This proposed mechanism contributes to the improvement of allergic airway inflammation and respiratory function in an asthmatic mouse model.

Co-delivery of homoharringtonine and doxorubicin boosts therapeutic efficacy of refractory acute myeloid leukemia

Refractory acute myeloid leukemia (AML) remains a challenging hematological malignancy to treat, due to the development of drug resistance, severe complications, and relapse in chemotherapies. Free-drugs combination has demonstrated enhanced therapeutic efficacy in AML, while it requires complicated administration regimens and brings added toxicity. To tackle this complex disease, in this work two clinically applied therapeutics, doxorubicin and homoharringtonine, were assembled into one polymeric micelle to form a co-delivery system (DHM) to facilitate a novel and simple administration regimen. The DHM was systematically investigated in the drug-resistant AML cell line HL60/A as well as in the AML1-ETO+-c-kit+ mouse featuring as a refractory and relapsed AML model following comprehensive characterizations. Compared with the free-drugs combination, DHM significantly enhanced the cellular uptake of the therapeutics, inhibited the cell division and induced a higher rate of cells apoptosis in vitro. More importantly, the intraperitoneal injection of DHM remarkably eradicated leukemia cells in the peripheral blood, bone marrow, spleen and liver of the AML mice and significantly prolonged the survival of the mice without additional systematic toxicity compared with that of the free-drugs combination. In conclusion, the DHM boosted the therapeutic effect of clinically applied chemodrugs as well as provided a novel platform for multi-drugs co-delivery against refractory and relapsed AML, therefore holding promising potential for translational medicine.

Heterogeneity of CD4+CD25+Foxp3+Treg TCR β CDR3 Repertoire Based on the Differences of Symbiotic Microorganisms in the Gut of Mice

Gut microbes play a crucial role in the occurrence and development of autoimmune diseases. The diversity of intestinal microorganisms affected by the living environment, regulate the immune function of peripheral immune organs and local tissues. In the study, the diversity of intestinal microorganisms of Germ-free (GF), Specific Pathogen-free (SPF), and Clean (CL) BALB/c mice were conducted by 16S rDNA sequencing. High-throughput sequencing technology was used to analysis the composition and characterization of TCR β chain CDR3 repertoires in Regulatory T cells (Treg) in intestine and spleen of GF, SPF, and CL mice, so as to investigate the effects of differential composition of intestinal microorganisms on the CD4+CD25+Foxp3+Treg TCR β CDR3 repertoire of intestine and spleen. We observed that GF, SPF, and CL mice have different gut microorganism composition, and the abundance and quantity of microorganisms are positively correlated with the level of feeding environment. Interestingly, incomplete structure of spleen and small intestine in GF mice was found. Moreover, a significant difference in the usage of high frequency unique CDR3 amino acid sequences was detected in the intestinal Treg TCRβ CDR3 repertoire among GF, SPF and CL mice, and there were a greater heterogeneity in the usage frequency of TRBV, TRBJ, and TRBV-TRBJ combinations gene segments. However, the effect of different feeding environment on the mice Treg TCRβ CDR3 repertoire of spleen was weak, implying that the different composition of intestinal microbiota may primarily affect the diversity of the local Treg TCRβ CDR3 repertoire and does not alter the overall properties of the circulating immune system. These results provide basic data to further analyze the mechanism of gut microbes regulating the intestinal mucosal immune system.

MiR-374b-5p Regulates T Cell Differentiation and Is Associated with rEg.P29 Immunity

Cystic echinococcosis (CE) is a zoonotic disease caused by Echinococcus granulosus (Eg) infection. Our previous study confirmed that recombinant Eg.P29 (rEg.P29) could protect against echinococcus granulosus secondary infection in sheep and mice. The aim of the study was to investigate the association between immunoprotection of rEg.P29 vaccine and mmu-miR-374b-5p (miR-374b-5p) and study the immunity influence of miR-374b-5p on CD4+ T cells in mice spleen. MiR-374b-5p level was significantly increased after the second-week and the fourth week of vaccination with rEg.P29. Overexpression of miR-374b-5p increased IFN-γ, IL-2, IL-17A mRNA levels and decreased IL-10 mRNA levels in CD4+ T cells. Moreover, the inhibition of miR-374b-5p decreased IFN-γ and IL-17A and increased IL-10 mRNA levels in CD4+ T cells; this was further confirmed by the flow cytometry. The vaccination of rEg.P29 enhanced miR-374b-5p expression that was associated with a higher Th1 and Th17 immune response, a lower IL-10 mRNA production with miR-374b-5p overexpression, a lower Th1 immune response, and a higher IL-10 mRNA levels with miR-374b-5p inhibitions. To sum up, these data suggest that miR-374b-5p may participate in rEg.P29 immunity by regulating Th1 and Th17 differentiation.

Abstract 525: A novel anti-PD1-IL15 immunocytokine potentiates anti-tumor T cell activity of PD-1 checkpoint inhibition and IL-2R-beta-gamma agonism

Abstract Therapeutic antibodies targeting immune checkpoint inhibitors (ICI) such as PD-1/PD-L1 effectively expand and reactivate T cells in patients, leading to long-lasting response in multiple tumor types. However, only a fraction of patients responded to approved ICIs, majority are either resistant or quickly become refractory. Other immunotherapy modalities including immunostimulatory cytokines IL-2, IL-12 and IL-15 demonstrated clinical benefits as monotherapy or in combination with ICIs. Cytokines exhibit in general a short half-life and systemic toxicities that limit their use as the optimal doses in treating cancer. An antibody-based immunocytokine fusion such as Kadmon lead candidate KD033 (anti-PDL1/IL15) and Roche anti-PD1/CEA/FAP-IL2v can extend the half-life of cytokine and reduce systemic toxicities. In this study, a fully human single-chain variable fragment (scFv) antibody against mouse PD1 (mPD1) have been isolated from the phage display library. The variable domains of these antibodies were fused to either human IgG1a or mouse IgG2a constant domain first, and then fused to either human IL15 receptor alpha sushi domain-hIL15 complex (hSD15) or mouse IL15 receptor alpha sushi domain-mIL15 complex (mSD15). These variations of fusion have been tested in in vitro binding and functional assays, and in vivo in PD1/PDL1 resistant mouse syngeneic model LL2 (Lewis Lung Carcinoma). We demonstrated that hSD15 fusion antibody can stimulate both IL2 dependent human and murine cells growth, surprisingly, mSD15 fusion antibody can only stimulate murine cell growth. Although mSD15 fusion antibody EC50 was 10 folds better than hSD15 fusion antibody in stimulating mouse spleen cell growth in vitro, it did not show a better efficacy than hSD15 fusion antibody in LL2 model. In vivo, mSD15 fusion antibody had higher maximum tolerate dose than hSD15 fusion antibody (up to 12mg/kg). In addition, anti-mPD1/mSD15 showed better efficacy than either the mIL15 and anti-mPD1 alone or the combination of anti-mPD1 plus mIL15 in vitro and in vivo. Together these preclinical data have confirmed that PD1-IL15 could be a promising next generation IL-15 fusion for cancer immunotherapy. Citation Format: Dan Lu, Zhanna Polonskaya, Tzi-Pei Chang, Stella Martomo, Xenia Luna, Zhikai Zhang, Faical Miyara, Jeedar Patel. A novel anti-PD1-IL15 immunocytokine potentiates anti-tumor T cell activity of PD-1 checkpoint inhibition and IL-2R-beta-gamma agonism [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 525.

Immunomodulatory and antitumour bioactive labdane diterpenoids from Leonurus japonicus.

Two labdane diterpenoids, leojapone B and heteronone B, were isolated from Leonurus japonicus Houtt., and their biological activity were evaluated in this study. Human and mouse cancer cells, human peripheral blood mononuclear cells (PBMCs) and mouse macrophages (RAW264.7 cells) were used to evaluate the activity of leojapone B and heteronone B, while the in vivo effects of leojapone B were further examined in Lewis Lung Cancer tumour-bearing mice. In vitro studies showed that leojapone B selectively inhibited the proliferation of lung cancer cells, and both leojapone B and heteronone B inhibited the production of pro-inflammatory cytokines in activated PBMCs. In tumour-bearing mice model, lung tumours were reduced in size in mice treated with intraperitoneal injections of leojapone B at 20 and 30mg/kg for 14days. The population ratio of CD4+ /CD8+ T cells in mouse spleens was found to be increased, while regulatory T cells were decreased after leojapone B treatment. The inhibitory effects of leojapone B in mouse lung tumours were demonstrated for the first time in this study. The immunomodulatory activity of heteronone B were also demonstrated. Our findings indicated that both leojapone B and heteronone B may act as active components in L.japonicus.

A Novel In Vitro Mouse Model to Study Mycobacterium tuberculosis Dissemination Across Brain Vessels: A Combination Granuloma and Blood‐Brain Barrier Mouse Model

In vitro culture models of the blood-brain barrier (BBB) provide a useful platform to test the mechanisms of cellular infiltration and pathogen dissemination into the central nervous system (CNS). We present an in vitro mouse model of the BBB to test Mycobacterium tuberculosis (Mtb) dissemination across brain endothelial cells. One-third of the global population is infected with Mtb, and in 1%-2% of cases bacteria invade the CNS through a largely unknown process. The "Trojan horse" theory supports the role of a cellular carrier that engulfs bacteria and carries them to the brain without being recognized. We present for the first time a protocol for an in vitro BBB-granuloma model that supports the Trojan horse mechanism of Mtb dissemination into the CNS. Handling of bacterial cultures, in vivo and in vitro infections, isolation of primary astroglial and endothelial cells, and assembly of the in vitro BBB model is presented. These techniques can be used to analyze the interaction of adaptive and innate immune system cells with brain endothelial cells, cellular transmigration, BBB morphological and functional changes, and methods of bacterial dissemination. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Isolation of primary mouse brain astrocytes and endothelial cells Basic Protocol 2: Isolation of primary mouse bone marrow-derived dendritic cells Support Protocol 1: Validation of dendritic cell purity by flow cytometry Basic Protocol 3: Isolation of primary mouse peripheral blood mononuclear cells Support Protocol 2: Isolation of primary mouse spleen cells Support Protocol 3: Purification and validation of CD4+ T cells from PBMCs and spleen cells Basic Protocol 4: Isolation of liver granuloma supernatant and determination of organ load Support Protocol 4: In vivo and in vitro infection with mycobacteria Basic Protocol 5: Assembly of the BBB co-culture model Basic Protocol 6: Assembly of the combined in vitro granuloma and BBB model.