Mouse Splenocytes Research Articles

Significance of CD10 for Mucosal Immunomodulation by β-Casomorphin-7 in Exacerbation of Ulcerative Colitis.

β-Casomorphin-7 (BCM), a breakdown product of milk β-casein, exhibits opioid activity. Opioids are known to affect the immune system, but the effects of BCM on ulcerative colitis (UC) are not clear. We examined the effects of BCM on mucosal immunity using a mouse dextran sulfate sodium-induced colitis model and an in vitro CD8+ T cell activation model. Human UC patients were examined to reveal the relationship between CD10 and mucosal immunity. Combined treatment of the colitis model with thiorphan (TOP) inhibited BCM degradation by suppressing CD10 in the intestinal mucosa, activating mouse mucosal CD8, and suppressing CD4 and Treg. In the CD8+ T cell in vitro activation assay using mouse splenocytes, BCM inhibited the oxidative phosphorylation (OXPHOS) of CD8+ T cells and induced the glycolytic pathway, promoting their activation. Conversely, in a culture system, BCM suppressed OXPHOS and decreased defensin α production in IEC6 mouse intestinal epithelial cells. In the mouse model, BCM reduced defensin α and butyrate levels in the colonic mucosa. During the active phase of human ulcerative colitis, the downward regulation of ileal CD10 expression by CpG methylation of the gene promoter was observed, resulting in increased CD8 activation and decreased defensin α and butyrate levels. BCM is a potential aggravating factor for UC and should be considered in the design of dietary therapy. In addition, decreased CD10 expression may serve as an indicator of UC activity and recurrence, but further clinical studies are needed.

An antibody to IL-1 receptor 7 protects mice from LPS-induced tissue and systemic inflammation.

Interleukin-18 (IL-18), a pro-inflammatory cytokine belonging to the IL-1 Family, is a key mediator ofautoinflammatory diseases associated with the development of macrophage activation syndrome (MAS).High levels of IL-18 correlate with MAS and COVID-19 severity and mortality, particularly in COVID-19patients with MAS. As an inflammation inducer, IL-18 binds its receptor IL-1 Receptor 5 (IL-1R5), leadingto the recruitment of the co-receptor, IL-1 Receptor 7 (IL-1R7). This heterotrimeric complex subsequentlyinitiates downstream signaling, resulting in local and systemic inflammation. We reported earlier the development of a novel humanized monoclonal anti-human IL-1R7 antibody whichspecifically blocks the activity of human IL-18 and its inflammatory signaling in human cell and wholeblood cultures. In the current study, we further explored the strategy of blocking IL-1R7 inhyperinflammation in vivo using animal models. We first identified an anti-mouse IL-1R7 antibody that significantly suppressed mouse IL-18 andlipopolysaccharide (LPS)-induced IFNg production in mouse splenocyte and peritoneal cell cultures. Whenapplied in vivo, the antibody reduced Propionibacterium acnes and LPS-induced liver injury and protectedmice from tissue and systemic hyperinflammation. Importantly, anti-IL-1R7 significantly inhibited plasma,liver cell and spleen cell IFNg production. Also, anti-IL-1R7 downregulated plasma TNFa, IL-6, IL-1b,MIP-2 production and the production of the liver enzyme ALT. In parallel, anti-IL-1R7 suppressed LPSinducedinflammatory cell infiltration in lungs and inhibited the subsequent IFNg production andinflammation in mice when assessed using an acute lung injury model. Altogether, our data suggest that blocking IL-1R7 represents a potential therapeutic strategy to specificallymodulate IL-18-mediated hyperinflammation, warranting further investigation of its clinical application intreating IL-18-mediated diseases, including MAS and COVID-19.

Immunogenicity of PvCyRPA, PvCelTOS and Pvs25 chimeric recombinant protein of Plasmodium vivax in murine model.

In the Americas, P. vivax is the predominant causative species of malaria, a debilitating and economically significant disease. Due to the complexity of the malaria parasite life cycle, a vaccine formulation with multiple antigens expressed in various parasite stages may represent an effective approach. Based on this, we previously designed and constructed a chimeric recombinant protein, PvRMC-1, composed by PvCyRPA, PvCelTOS, and Pvs25 epitopes. This chimeric protein was strongly recognized by naturally acquired antibodies from exposed population in the Brazilian Amazon. However, there was no investigation about the induced immune response of PvRMC-1. Therefore, in this work, we evaluated the immunogenicity of this chimeric antigen formulated in three distinct adjuvants: Stimune, AddaVax or Aluminum hydroxide (Al(OH)3) in BALB/c mice. Our results suggested that the chimeric protein PvRMC-1 were capable to generate humoral and cellular responses across all three formulations. Antibodies recognized full-length PvRMC-1 and linear B-cell epitopes from PvCyRPA, PvCelTOS, and Pvs25 individually. Moreover, mice's splenocytes were activated, producing IFN-γ in response to PvCelTOS and PvCyRPA peptide epitopes, affirming T-cell epitopes in the antigen. While aluminum hydroxide showed notable cellular response, Stimune and Addavax induced a more comprehensive immune response, encompassing both cellular and humoral components. Thus, our findings indicate that PvRMC-1 would be a promising multistage vaccine candidate that could advance to further preclinical studies.

Protective Efficacy of a Novel DNA Vaccine with a CL264 Molecular Adjuvant against Toxoplasma gondii in a Murine Model.

Toxoplasmosis is a significant global zoonosis with devastating impacts, and an effective vaccine against toxoplasmosis for humans has not yet been developed. In this study, we designed and formulated a novel DNA vaccine encoding the inhibitor of STAT1 transcriptional activity (IST) of T. gondii utilizing the eukaryotic expression vector pEGFP-N1 for the first time, with CL264 being a molecular adjuvant. Following intramuscular injection of the vaccine into mice, the levels of antibodies and cytokines were assessed to evaluate the immune response. Additionally, mice were challenged with highly virulent RH-strain tachyzoites of T. gondii, and their survival time was observed. The results show that the levels of IgG in serum, the ratio of IgG2a/IgG1 and the levels of IFN-γ in splenocytes of mice were significantly higher in the pEGFP-TgIST group and the pEGFP-TgIST + CL264 group than in the control group. In addition, the proportion of CD4+/CD8+ T cells was higher in mice immunized with either the pEGFP-TgIST group (p < 0.001) or the pEGFP-TgIST + CL264 group (p < 0.05) compared to the three control groups. Notably, TgIST-immunized mice exhibited prolonged survival times after T. gondii RH strain infection (p < 0.05). Our findings collectively demonstrate that the TgIST DNA vaccine elicits a significant humoral and cellular immune response and offers partial protection against acute T. gondii infection in the immunized mice, which suggests that TgIST holds potential as a candidate for further development as a DNA vaccine.

Heat-killed Akkermansia muciniphila ameliorates allergic airway inflammation in mice.

Allergic asthma (AA) is a common inflammatory airway disease characterized by increased airway hyper-responsiveness (AHR), inflammation, and remodeling. Akkermansia muciniphila is a strictly anaerobic bacterium residing in the gut and is a promising next-generation probiotic to improve metabolic inflammatory syndrome. A recent study suggested the beneficial effect of live A. muciniphila on allergic airway inflammation (AAI) in mice. However, whether the heat-killed form can improve AAI requires further investigation. Mice sensitized and challenged with house dust mites (HDM) develop AA hallmarks including inflammatory cell infiltration, goblet cell hyperplasia, and subepithelial collagen deposition in the lungs. These phenomena were reversed by oral administration of the heat-killed A. muciniphila strain EB-AMDK19 (AMDK19-HK) isolated from the feces of healthy Koreans. Furthermore, AMDK19-HK diminished the HDM-induced AHR to inhaled methacholine, lung mast cell accumulation, and serum HDM-specific IgE levels. It also led to the overall suppression of IL-4, IL-13, and eotaxin production in bronchoalveolar lavage fluids, and Il4, Il5, Il13, and Ccl17 gene expression in lung tissues. Moreover, AMDK19-HK suppressed Th2-associated cytokine production in the splenocytes of HDM-sensitized mice in vitro. Additionally, a combination of 16S rRNA gene sequencing and short-chain fatty acid (SCFA) analysis in cecal samples revealed that AMDK19-HK modulated the relative abundance of circulating SCFA-associated gut genera, including a positive correlation with Lachnospiraceae_ NK4A136_group and a negative correlation with Lachnoclostridium and significantly increased cecal SCFA concentrations. Finally, AMDK19-HK improved intestinal mucosal barrier function. These results suggest that the oral administration of AMDK19-HK ameliorates HDM-induced AAI in mice by suppressing Th2-mediated immune responses and could have a protective effect against AA development.

StarBright Dyes — Simplifying Flow Cytometry with 8-color No Compensation Panels

Abstract Flow cytometry is a powerful technique, allowing a vast amount of information to be obtained from a single sample. A well-designed panel is vital for good quality data. One aspect of panel design is to use fluorophore combinations that avoid close or overlapping spectra. If not, the panel will risk having high spillover, spreading, and reduced population resolution. We have designed 8-color, no compensation panels for conventional flow cytometry where the fluorophores used have distinct spectra, therefore they have minimal signal into detection filters other than their own. This removes the need for post-acquisition compensation, saving time, as well as ensuring high resolution of cells due to the lack of spread. We show 8-color immunophenotyping panels, acquired on a 5-laser ZE5 Cell Analyzer, for human peripheral blood and mouse splenocytes which require no compensation. B cell, cytotoxic and memory T cell, natural killer cell, and monocyte populations were easily identified. These panels can also be used as a backbone for building larger panels by adding additional markers to detect other cells of interest. Many antibodies incorporated into these panels, have been conjugated to StarBrightTM Dyes which have narrow excitation and emission profiles, making them ideal for inclusion in no compensation panels. StarBright Dyes also simplify panel design as they work with all buffers and most fixatives making them suitable for use in a wide range of protocols.

Neuropeptide Y affects B-cell activation functions

Introduction: Sympathetic nerves secrete neurotransmitters in response to pathogenic organisms in various immunological contexts. Most studies have focused on norepinephrine (NE) which has shown numerous immunomodulatory effects involving pro- and anti-inflammatory responses. However, sympathetic neurons contain also varicosities where neuropeptides, mainly neuropeptide Y (NPY), are stored. NPY play roles in various physiological processes, including regulating metabolism, vascular function, and immune function but little is known on its action during bacterial respiratory infection. The regulation of its secretion and its impact on the immune system during infection remains unclear. We investigated the role of NPY in B-cell responses during bacterial infection. Methods: Naïve B-cells isolated from mice splenocytes (2M/2F) were stimulated with IL-4 and LPS, along with NE or NPY. After 96 hours, cells were stained and analyzed by flow cytometry and transcripts were isolated for quantitative real-time PCR. Media was collected until immunoglobulin analysis. To investigate NPY role during infection, we used a mice model of bacterial lung infection. Mice were intranasally exposed twice with streptococcus pneumoniae (serotype 19F on day 0: 104 CFU and on day 9: 108 CFU); experiments took place 16 hours later. Control animals were infused with vehicle only. Results: Apart from beta2-adrenergic receptor, isolated B-cells were found to express alpha2- and beta1-adrenergic receptor transcripts. In vitro stimulation of B-cell with IL-4 and LPS (T-cell independent activation) downregulated beta-adrenergic and upregulated alpha2-adrenergic, as well as NPY receptors (Npy1r, Npy2r, Npy4r, Npy5r). Unlike NE, NPY has shown to affect B-cell proliferation and drastically increases IgG positive-cells during stimulation. However, neither NE nor NPY seem to regulate IgG release in this condition. In vivo experiments indicate that NPY level increased in the lung in response to streptococcal challenge, contrasting with the unchanged levels of NE. Conclusion: Our findings contribute to our understanding of how sympathetic neurotransmitters regulates B-cell expansion, memory, and antibody production during infection. Furthermore, our research gives new insights into the function(s) and antimicrobial capacity of neuropeptide Y. These findings allow for the development of new and more effective therapeutic strategies for invasive bacterial infections. 1R21AI159221, UCOP TRDRP T32KT4708. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Lactobacillus plantarum isolated from kimchi regulates inflammation by increasing interleukin-10 secretion by antigen-presenting cells, leading to diminishing of STAT5 phosphorylation in Th2 cells.

The relationship between allergic inflammation and gut microbiota has been elucidated, and the effect of probiotics on immune disorders has been studied as well. Identifying the role of probiotics in individual diseases and immune responses and selecting and applying specific microorganisms based on these findings can be an effective strategy for using probiotics. Herein, lactobacilli isolated from kimchi were investigated in depth, focusing on their immune regulatory effects and the mechanisms involved. Lactic acid bacteria (LAB) effectively diminished the increased secretion of T helper 2 cytokines, such as IL-4, IL-5, and IL-13, from ovalbumin (OVA)-sensitized mouse splenocytes. The gene expression of GATA3, IL-4, IL-5, IL-9, and IL-13 was confirmed to be regulated by LAB. LAB also suppressed IL-2 production and STAT5 phosphorylation. An IL-10-neutralizing antibody attenuated these effects, indicating that LAB-induced upregulation of IL-10 in antigen-presenting cells was responsible at least partially for the increased IL-2 production and STAT5 phosphorylation in CD4+ T cells. In conclusion, the current study identified one immunomodulatory mechanism that allows LAB to regulate allergic immune reactions and the potential of LAB from kimchi to modulate various immune reactions.

A novel sORF gene mutant strain of Yersinia pestis vaccine EV76 offers enhanced safety and improved protection against plague.

We recently identified two virulence-associated small open reading frames (sORF) of Yersinia pestis, named yp1 and yp2, and null mutants of each individual genes were highly attenuated in virulence. Plague vaccine strain EV76 is known for strong reactogenicity, making it not suitable for use in humans. To improve the immune safety of EV76, three mutant strains of EV76, Δyp1, Δyp2, and Δyp1&yp2 were constructed and their virulence attenuation, immunogenicity, and protective efficacy in mice were evaluated. All mutant strains were attenuated by the subcutaneous (s.c.) route and exhibited more rapid clearance in tissues than the parental strain EV76. Under iron overload conditions, only the mice infected with EV76Δyp1 survived, accompanied by less draining lymph nodes damage than those infected by EV76. Analysis of cytokines secreted by splenocytes of immunized mice found that EV76Δyp2 induced higher secretion of multiple cytokines including TNF-α, IL-2, and IL-12p70 than EV76. On day 42, EV76Δyp2 or EV76Δyp1&yp2 immunized mice exhibited similar protective efficacy as EV76 when exposed to Y. pestis 201, both via s.c. or intranasal (i.n.) routes of administration. Moreover, when exposed to 200-400 LD50 Y. pestis strain 201Δcaf1 (non-encapsulated Y. pestis), EV76Δyp2 or EV76Δyp1&yp2 are able to afford about 50% protection to i.n. challenges, significantly better than the protection afforded by EV76. On 120 day, mice immunized with EV76Δyp2 or EV76Δyp1&yp2 cleared the i.n. challenge of Y. pestis 201-lux as quickly as those immunized with EV76, demonstrating 90-100% protection. Our results demonstrated that deletion of the yp2 gene is an effective strategy to attenuate virulence of Y. pestis EV76 while improving immunogenicity. Furthermore, EV76Δyp2 is a promising candidate for conferring protection against the pneumonic and bubonic forms of plague.

Expanding a peptide-covalent probe hybrid for PET imaging of S. aureus driven focal infections

BackgroundThe urgent demand for innovative theranostic strategies to combat bacterial resistance to antibiotics is evident, with substantial implications for global health. Rapid diagnosis of life-threatening infections can expedite treatment, improving patient outcomes. Leveraging diagnostic modalities i.e., positron emission tomography (PET) and single photon emission computed tomography (SPECT) for detecting focal infections has yielded promising results. Augmenting the sensitivity of current PET and SPECT tracers could enable effective imaging of pathogenic bacteria, including drug-resistant strains.UBI (29–41), an antimicrobial peptide (AMP) fragment recognizes the S. aureus membrane through electrostatic binding. Radiolabeled UBI (29–41) is a promising SPECT and PET-based tracer for detecting focal infections. 2-APBA (2-acetyl-phenyl-boronic acid), a non-natural amino acid, specifically targets lysyl-phosphatidyl-glycerol (lysyl-PG) on the S. aureus membranes, particularly in AMP-resistant strains. We propose that combining UBI with 2-APBA could enhance the diagnostic potential of radiolabeled UBI.ResultsPresent work aimed to compare the diagnostic potential of two radiolabeled peptides, namely UBI (29–41) and 2-APBA modified UBI (29–41), referred to as UBI and UBI-APBA. APBA modification imparted antibacterial activity to the initially non-bactericidal UBI against S. aureus by inducing a loss of membrane potential. The antibacterial activity demonstrated by UBI-APBA can be ascribed to the synergistic interaction of both UBI and UBI-APBA on the bacterial membrane. To enable PET imaging, we attached the chelator 1,4,7-triazacyclononane 1-glutaric acid 4,7-acetic acid (NODAGA) to the peptides for complexation with the positron emitter Gallium-68 (68Ga). Both NODAGA conjugates were radiolabeled with 68Ga with high radiochemical purity. The resultant 68Ga complexes were stable in phosphate-buffered saline and human serum. Uptake of these complexes was observed in S. aureus but not in mice splenocytes, indicating the selective nature of their interaction. Additionally, the APBA conjugate exhibited superior uptake in S. aureus while preserving the selectivity of the parent peptide. Furthermore, [68Ga]Ga-UBI-APBA demonstrated accumulation at the site of infection in rats, with an improved target-to-non-target ratio, as evidenced by ex-vivo biodistribution and PET imaging.ConclusionsOur findings suggest that linking UBI, as well as AMPs in general, with APBA shows promise as a strategy to augment the theranostic potential of these molecules.

Abstract 2809: Bifidobacterium species BB_003 identified through metatranscriptomic analysis with experimentally validated antitumor actions

Abstract Introduction &amp; Objectives: A host's microbiome influences both gene expression and phenotype. Whole transcriptome sequencing (WTS) provides information about the microbiome in addition to gene expression. This research probes the correlation between microbial abundance, host gene transcription, and therapeutic efficacy, pinpointing a beneficial microbial strain and its mechanism of action. Materials &amp; Methods: Bladder tissue biopsies from NMIBC patients underwent WTS and subsequent bioinformatic analysis. After in silico evaluation, in vitro assays including WST, quantitative PCR, and immune cell profiling were performed on mouse splenocytes. These assays were followed by in vivo assessment in both subcutaneous and orthotopic murine tumor models. Results: Among 59 biopsies, non-recurrence correlated with heightened presence of Lactococcus species LC_001 and Bifidobacterium species BB_003. Notably, BB_003 was associated with an extended recurrence-free survival (RFS). Gene set enrichment analysis (GSEA) implicated BB_003 in mediating a pro-inflammatory cascade, accentuating macrophages and interferons. In vitro WST assays showed the antitumor potential of BB_003_β, characterized by upregulated pro-inflammatory gene transcription. This strain increased effector CD8 T cells and M2 macrophages. In vivo, direct live BB_003_β introduction into subcutaneous tumors curtailed tumor proliferation. An increase in effector CD8 T cell populations within tumors and elevated cDC1 and M1 macrophage counts in tumor-draining lymph nodes were observed. Intravesical administration of live bacteria markedly decreased bladder weight, amplifying interferon alpha and beta gene expressions compared to controls. Conclusions: According to this study, BB_003_β inhibits tumor growth and is involved in immune response. Our study confirmed the antitumor properties of BB_003_β and suggested that cytokine and immune cell stimulation play a key role in its mechanism of action. Augmented insights warrant further exploration, particularly in synergy with intravesical BCG treatment. Citation Format: Xuan-Mei Piao, Kyungchan Min, Young Joon Byun, Chuang-Ming Zheng, Seon-Kyu Kim, Seong-Hwan Park, Sungmin Moon, Kyeong Kim, Ho Won Kang, Won Tae Kim, Seok Joong Yun, Hansoo Park. Bifidobacterium species BB_003 identified through metatranscriptomic analysis with experimentally validated antitumor actions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2809.

Abstract 2675: A new dual-targeting anti-immune checkpoint therapeutic approach for the treatment of “hot” and “cold” tumors

Abstract Anti-Immune Checkpoint (ICP) antibody approaches provided a major breakthrough in the field of cancer therapy. However, their efficiency is mainly restricted to patients with “hot” tumors characteristics, which limits the breadth of their use. To tackle this limit, we developed a new strategy aimed at amplifying anti-ICP antibody ability to activate immune cells. This approach is based on antibodies engineered to make them able to target both an ICP receptor and a co-receptor often involved in receptor-mediated activation, namely Heparan Sulfate Proteoglycan. The dually-targeting engineered anti-ICP antibodies were produced in eukaryotic cells. They were purified to homogeneity using two chromatographic steps and remain stable for months in frozen conditions. A first engineered antibody-derived construct was assessed for its ability to impact immune cell activation and tumor-growth. It is able to stimulate subsets of immune cells from mouse splenocytes as well as from human peripheral mononuclear cells, in vitro. In addition, its injection in healthy mice triggers activation of T-cells. Last, in mice previously implanted with different types of cancer cells it impacts growth of “hot” as well as “cold” tumors. Immune profiling in a “cold” cancer model shows that the treatment decreases the proportion of MDSCs and increase that of CD8+ T-cells and NK-cells in tumor microenvironment making it close of that found in “hot” tumors. Altogether, our data indicate that our first engineered antibody-derived construct presents an attractive immunotherapeutic potential for a large variety of cancers paving the way for its evaluation in clinical phases. Citation Format: Moutuaata M. Moutuou, Nora DeLuce, Elodie Creton, Honorine Lucchi, Julien Accolas, Alexandra Savatier, Michel Léonetti. A new dual-targeting anti-immune checkpoint therapeutic approach for the treatment of “hot” and “cold” tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2675.

Abstract 335: BD®OMICS-Guard Sample Preservation Buffer preserves mRNA and cell surface epitopes for single-cell sequencing applications

Abstract Multiomics has emerged as a powerful tool to derive insights on the transcriptomic and proteomic data of human cancer samples and preclinical models of blood and tumor malignancies. Due to the sensitivity of sequencing techniques, sample quality and stability can potentially interfere with results. BD® OMICS-Guard Sample Preservation Buffer (SPB), a novel preservation solution, allows cells and bulk tissues to be stored for up to 72h at 4 °C, while reliably capturing the true biology of cells. This reagent gently preserves mRNA and protein integrity without the traditional cross-linking and harsh fixatives, increasing flexibility and expanding options for study designs. Here, we showcase the preservation properties ofthis reagent for multiomic readouts in human cells and mouse tissue across three different timepoints.BD® OMICS-Guard SPB’s preservation of mRNA from human PBMC and bulk mouse spleen tissues wasevidenced by WTA for differentially expressed genes in samples preserved for 24, 48 and 72h comparedto fresh/unpreserved controls. Protein epitope preservation was demonstrated via CITE-Seq assay withthe BD® AbSeq Human Immune Discovery Panel (human PBMC) or a 30-plex panel of anti-mouse BD®AbSeq Antibody-Conjugated Oligonucleotides (mouse splenocytes) and confirmed with multicolor flowcytometry. For both sample types, high correlation R2 values (&amp;gt;0.87) were calculated for the preservation time points versus fresh controls. Concomitant flow cytometry analysis of major cell types and surface protein expression was consistent with sequencing data for all samples. Specificity and sensitivity of major cell type markers and cell surface proteins across cell types and time is visualized in the BD®AbSeq Antibody-generated heatmap for each sample. Additionally, BD® OMICS-Guard SPB maintains mRNA integrity in targeted gene assays and VDJ full-length assays, suggesting robust preservation of select transcripts readily interrogated in single-cell profiling. Batch effect across time and technical replicates for both sample types was limited with the BD Rhapsody™ HT Xpress System and delineated by donor/sample specific tSNEs across time. We demonstrate that the BD® OMICS-Guard Sample Preservation Buffer effectively preserves both mRNA and surface proteins for single-cell experiments. BD® OMICS-Guard SPB allows the convenient preservation of samples such as tumor biopsies to be collected and stored for up to 72h at 4 °C while maintaining mRNA and protein integrity, allowing the flexibility for precious samples to be potentially shipped to a central sequencing site to ensure standardized sequencing workflows. For Research Use Only. Not for use in diagnostic or therapeutic procedures.BD and BD Rhapsody are trademarks of Becton, Dickinson and Company or its affiliates. © 2023 BD. All rights reserved. Citation Format: Samuel X. Shi, Cynthia Sakofsky, Zhiqi Zhang, Samatha Vadrevu, Xiaoshan Shi, Hye-Won Song, Aruna Ayer. BD®OMICS-Guard Sample Preservation Buffer preserves mRNA and cell surface epitopes for single-cell sequencing applications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 335.

Abstract 6653: Oncolytic virotherapy induces a long-term immune antitumoral response leading to glioma eradication

Abstract Oncolytic herpes simplex viruses (oHSVs) have shown promise as effective treatments against various cancers. Our study evaluated the efficacy of R-115, an oHSV retargeted to human Her2 (hHer2), fully virulent in its target cells and expressing murine interleukin 12 (mIL12), in a high-grade, immunocompetent murine glioma model. This model is based on orthotopically transplant of cells derived from PDGFB-induced primary gliomas in syngeneic mice, engineered to express hHer2. Our experimental design compared the impact of R-115 on gliomas where all cells expressed hHer2 against a setup where only about 50% of cells expressed hHer2. The latter aimed to replicate the heterogeneity of patient’s high-grade gliomas, where not all cells express the target molecule. Strikingly, results in terms of overall survival and tumor eradication were similar in both setups, with about a quarter of animals showing complete glioma eradication. This suggests that mIL12-armed oHSV's impact is less about direct viral-induced cell death and more about the immune response elicited by the mIL12-expressing virus. This response effectively targets cells lacking the viral-targeted protein but likely sharing other neoantigens with hHer2-positive cells. Mice cured in both experimental setups were rechallenged with purely hHer2-negative cells. Almost all did not develop gliomas, indicating a strong immune response capable of rejecting the tumor. Plasma analysis revealed that R-115-treated mice from both setups were more immunoreactive against both hHer2-positive and negative cells compared to untreated mice. Further, co-culturing long-surviving mice's splenocytes with glioma cells showed increased cell division in CD8, CD4 and CD19 populations, and elevated IFN-γ, granzyme B, and TNF-α production. These findings underscore R-115's profound anti-cancer potential, especially its capacity to elicit an immune response effective against glioma cells, irrespective of their expression of the target molecule. This outcome, coupled with the results of the rechallenge experiments, is pivotal. It suggests that in a clinical context, an interleukin-12-expressing oHSV could effectively target not only residual cells post-surgical resection but also infiltrating cells that are distant from the site of virus administration. Encouraged by these promising findings, we are currently advancing our research with a novel oHSV that expresses mIL12 and targets EGFRvIII, a mutation found exclusively in tumor cells. This is aimed at enhancing the safety and translatability of this therapeutic approach. Citation Format: Francesca Piaggio, Francesco Alessandrini, Chiara Riviera, Irene Appolloni, Davide Ceresa, Daniela Marubbi, Tatiana Gianni, Gabriella Campadelli-Fiume, Paolo Malatesta. Oncolytic virotherapy induces a long-term immune antitumoral response leading to glioma eradication [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6653.

Heterologous DNA Prime/Protein Boost Immunization Targeting Nef-Tat Fusion Antigen Induces Potent T-cell Activity and in vitro Anti-SCR HIV-1 Effects.

Heterologous combinations in vaccine design are an effective approach to promote T cell activity and antiviral effects. The goal of this study was to compare the homologous and heterologous regimens targeting the Nef-Tat fusion antigen to develop a human immunodeficiency virus-1 (HIV-1) therapeutic vaccine candidate. At first, the DNA and protein constructs harboring HIV-1 Nef and the first exon of Tat as linked form (pcDNA-nef-tat and Nef-Tat protein) were prepared in large scale and high purity. The generation of the Nef-Tat protein was performed in the E. coli expression system using an IPTG inducer. Then, we evaluated and compared immune responses of homologous DNA prime/ DNA boost, homologous protein prime/ protein boost, and heterologous DNA prime/protein boost regimens in BALB/c mice. Finally, the ability of mice splenocytes to secret cytokines after exposure to single-cycle replicable (SCR) HIV-1 was compared between immunized and control groups in vitro. The nef-tat gene was successfully subcloned in eukaryotic pcDNA3.1 (-) and prokaryotic pET-24a (+) expression vectors. The recombinant Nef-Tat protein was generated in the E. coli Rosetta strain under optimized conditions as a clear band of ~ 35 kDa detected on SDS-PAGE. Moreover, transfection of pcDNA-nef-tat into HEK-293T cells was successfully performed using Lipofectamine 2000, as confirmed by western blotting. The immunization studies showed that heterologous DNA prime/protein boost regimen could significantly elicit the highest levels of Ig- G2a, IFN-γ, and Granzyme B in mice as compared to homologous DNA/DNA and protein/protein regimens. Moreover, the secretion of IFN-γ was higher in DNA/protein regimens than in DNA/DNA and protein/protein regimens after exposure of mice splenocytes to SCR HIV-1 in vitro. The chimeric HIV-1 Nef-Tat antigen was highly immunogenic, especially when applied in a heterologous prime/ boost regimen. This regimen could direct immune response toward cellular immunity (Th1 and CTL activity) and increase IFN-γ secretion after virus exposure.

Anti-Inflammatory Effects and Immunomodulatory Efficacy of Unitein (Fermented Glycine max, Panax ginseng, and Chenpi Mixture) in RAW 264.7 Macrophages and Mice Splenocytes along with Component Analysis

Inflammation and the immune system are intricately linked, with the immune system serving as a vital defense mechanism in the human body. Consequently, there is great emphasis placed on the regulation of both the body’s inflammatory response and the immune system. This study investigated the anti-inflammatory properties and immunomodulatory effects of Unitein (fermented Glycine max, Panax ginseng, and chenpi mixture) in both RAW 264.7 macrophages and mice splenocytes while also comprehensively analyzing its components. To this end, the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay was employed to evaluate the cytotoxicity of the samples to RAW 264.7 cells. The Griess assay was utilized to determine nitrite concentrations, while the enzyme-linked immunosorbent assay (ELISA) was employed to assess the levels of inflammation-related cytokines in RAW 264.7 cells and isolated mouse splenocytes. Additionally, quantitative polymerase chain reaction was employed to quantify the mRNA expression of inflammation-related genes in the cells, while the lactate dehydrogenase assay was used to analyze natural killer (NK) cell activity. Our results revealed that Unitein exhibited no toxicity to RAW 264.7 cells at concentrations below 1.5 mg/mL. However, Unitein effectively suppressed the release of proinflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and interferon (IFN)-γ, as well as enzymes COX-2 and iNOS from RAW 264.7 cells, while concurrently promoting the release of anti-inflammatory cytokines IκB-α, IL-10, and IL-4. Furthermore, Unitein inhibited the increase in TNF-α, IL-1β, IFN-γ, IL-12, nuclear factor (NF)-κB p50, NF-κB p65, and iNOS induced by lipopolysaccharides (LPSs) in isolated mouse splenocytes. Notably, Unitein also exhibited the potential to stimulate NK cell activity. Metabolite analysis indicated that Unitein contained more active compounds with anti-inflammatory and immunity-enhancing properties than did unfermented Unitein. This study highlights the potential therapeutic role of Unitein in mitigating inflammation and enhancing immune responses, thereby deepening our understanding of its biological activities and underlying mechanisms. These findings underscore the significance of Unitein as a potential candidate for the development of novel anti-inflammatory and immunomodulatory interventions.

In vitro immunoregulatory role of recombinant Ancylostoma ceylanicum calreticulin.

Ancylostoma ceylanicum is a zoonotic soil-derived nematode that parasitizes the intestines of humans and animals (dogs and cats), leading to malnutrition and iron-deficiency anemia. Helminth parasites secrete calreticulin (CRT), which regulates or blocks the host's immune response. However, no data on A. ceylanicum calreticulin (Ace-CRT) are available. We investigated the biological function of recombinant Ace-CRT (rAce-CRT). rAce-CRT showed reliable antigenicity and stimulated the proliferation of mouse splenocytes and canine peripheral blood mononuclear cells. Quantitative reverse-transcription PCR assays revealed that rAce-CRT primarily promoted the expression of T helper 2 cytokines, particularly IL-13, in canine peripheral blood lymphocytes. rAce-CRT inhibited complement-mediated sheep erythrocyte hemolysis in vitro. Our findings indicate that Ace-CRT plays an immunomodulatory role and may be a promising candidate molecule for a hookworm vaccine.

A41 IDENTIFICATION OF MICROBIAL LYSOPHOSPHATIDYLCHOLINE (LPC) AND LYSOPHOSPHATIDIC ACID (LPA) PRODUCERS AND THEIR EFFECTS ON THE HOST

Abstract Background Gut microbiota plays a key role in shaping our immune system, producing a myriad of molecules with neuro- and immunomodulatory properties. Many of these bioactive molecules are generated by bacterial metabolism of common dietary components. We have recently found that fecal samples of patients with chronic abdominal pain contain high levels of inflammatory phospholipids, lysophosphatidylcholine (LPC) and its active metabolite lysophosphatidic acid (LPA). Both phospholipids have been previously linked to genesis and maintenance of chronic neuropathic pain. In addition, they appear to have pro-inflammatory properties. Aims To investigate whether gut bacteria can produce LPC and LPA from dietary precursor phosphatidylcholine (PC), and whether these phospholipids can induce inflammatory responses in the host. Methods Fecal samples from patients with chronic abdominal pain were analyzed for microbial profiles using 16S rRNA (Illumina) analysis, and abundance of individual bacteria was correlated with fecal LPC and LPA levels as measured by ELISA. To confirm ability to produce these lipids, identified bacteria were incubated with either phosphatidylcholine (PC) or LPC (the immediate precursors of LPC and LPA, respectively) and LPC and LPA levels measured using liquid chromatography-mass spectrometry. To investigate pro-inflammatory effect of LPC and LPA, mouse splenocytes were incubated with LPC and/or LPA in vitro, and tested for cytokine production. Results Higher abundance of several bacterial species was associated with higher fecal levels of LPC and LPA. Among them, a bacterium from family Oscillospiraceae was identified as the most likely producer of both LPA and LPC; its abundance also correlated with high pain scores. Culturing and incubating this bacterium with PC and LPC resulted in a significant production of LPC and LPA. Additionally, LPA, but not LPC, resulted in increased levels of IL-6 production by splenocytes in vitro compared to the PBS only control. Interestingly, LPA induced IL-6 secretion was inhibited in the presence of LPC. Conclusions We have identified several bacterial producers of LPC and LPA, among them a bacterium from family Oscillospiraceae, which was also associated with high abdominal pain scores. LPA, but not LPC, seems to induce proinflammatory responses in the host. Further experiments are needed to identify the specific mechanisms by which these bioactive phospholipids induce abdominal pain and immune responses in the host. Funding Agencies CIHRFarncombe Family Digestive Health Research Institute

NAD+ affects differentially expressed genes-MBOAT2-SLC25A21-SOX6 in experimental autoimmune encephalomyelitis model

Background Nicotinamide adenine dinucleotide (NAD+) plays a key role in neuroinflammation and neurodegeneration and provides anti-inflammatory and neuroprotective effects in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). Aim In this study, we aimed to investigate whether NAD+ affects differentially expressed genes (DEGs) in splenocytes of EAE mice to reveal candidate genes for the pathogenesis of MS. Methods The EAE model was used to perform an intervention on NAD+ to investigate its potential as a protective agent in inflammation and demyelination. Transcriptome analysis of nerve tissue was carried out to gain better insights into NAD+ function. Effects of NAD+ on DEGs in the splenocytes of EAE mice were investigated to determine its anti-inflammatory effect. Results NAD+ in EAE mice showed the clinical score was significantly improved (EAE 3.190 ± 0.473 vs. NAD+ 2.049 ± 0.715). DEGs (MBOAT2, SLC25A21, and SOX6) between the EAE and the EAE + NAD+ groups showed that SOX6 was significantly improved after NAD+ treatment compared with the EAE group, and other indicators were improved but did not reach statistical significance. NAD+ exhibited clinical scores in EAE mice, and key inflammation was ameliorated in EAE mice spleen after NAD+ intervention, while transcriptome analysis between EAE and EAE + NAD+ groups showed several DEGs in the underlying mechanism. Conclusion NAD+ on DEGs attenuates disease severity in EAE. Transcriptome analysis on nerve tissue reveals several protein targets in the underlying mechanisms. However, NAD+ does not significantly improve DEGs in the splenocytes of the EAE model.

Cell-free chromatin particles released from dying cancer cells activate immune checkpoints in human lymphocytes: implications for cancer therapy.

Immune checkpoint blockade is the exciting breakthrough in cancer, but how immune checkpoints are activated is unknown. We have earlier reported that cell-free chromatin particles (cfChPs) that circulate in blood of cancer patients, or those that are released locally from dying cancer cells, are readily internalized by healthy cells with biological consequences. Here we report that treatment of human lymphocytes with cfChPs isolated from sera of cancer patients led to marked activation of the immune checkpoints PD-1, CTLA-4, LAG-3, NKG2A, and TIM-3. This finding was corroborated in vivo in splenocytes of mice when cfChPs were injected intravenously. Significant upregulation of immune checkpoint was also observed when isolated lymphocytes were exposed to conditioned medium containing cfChPs released from hypoxia-induced dying HeLa cells. Immune checkpoint activation could be down-regulated by pre-treating the conditioned media with three different cfChPs deactivating agents. Down-regulation of immune checkpoints by cfChPs deactivating agents may herald a novel form of immunotherapy of cancer.