OMIP-079: Cell cycle of CD4+ and CD8+ naïve/memory T cell subsets, and of Treg cells from mouse spleen

A 30-color spectral flow cytometry panel for comprehensive analysis of immune cell composition and macrophage subsets in mouse metabolic organs

Obesity-induced chronic low-grade inflammation, also known as metaflammation, results from alterations of the immune response in metabolic organs and contributes to the development of fatty liver diseases and type 2 diabetes. The diversity of tissue-resident leukocytes involved in these metabolic dysfunctions warrants an in-depth immunophenotyping in order to elucidate disease etiology. Here, we present a 30-color, full spectrum flow cytometry panel, designed to (i) identify the major innate and adaptive immune cell subsets in murine liver and white adipose tissues and (ii) discriminate various tissue-specific myeloid subsets known to contribute to the development of metabolic dysfunctions. This panel notably allows for distinguishing embryonically-derived liver-resident Kupffer cells from newly recruited monocyte-derived macrophages and KCs. Furthermore, several adipose tissue macrophage (ATM) subsets, including perivascular macrophages, lipid-associated macrophages, and pro-inflammatory CD11c+ ATMs, can also be identified. Finally, the panel includes cell-surface markers that have been associated with metabolic activation of different macrophage and dendritic cell subsets. Altogether, our spectral flow cytometry panel allows for an extensive immunophenotyping of murine metabolic tissues, with a particular focus on metabolically-relevant myeloid cell subsets, and can easily be adjusted to include various new markers if needed.

Intranasal delivery of a self-adjuvanted nanovaccine composed of the curli filaments and the highly conserved M2e epitope confers protection against influenza a virus in mice

Intranasal administration of vaccines is an attractive delivery route to fight viral respiratory infections. However, there are only a few intranasal vaccines used in human, emphasizing the critical need to identify novel safe mucosal adjuvants and antigen delivery systems to expand their usage. We recently revealed an immunostimulating nanoparticle based on a fragment (R4R5) of the Curli-specific gene A (CsgA) protein that confers protection against influenza A virus (IAV) when conjugated to three repeats of the highly conserved M2e epitope and administrated intramuscularly. Herein, the efficacy of this 3M2e-R4R5 nanovaccine was investigated upon administration by intranasal instillation. By triggering robust M2e-specific humoral and cellular responses, both systemic and locally in the respiratory tract, and by priming alveolar macrophages, the intranasal vaccine protected mice against a lethal IAV challenge without the use of additional adjuvant. Thus, CsgA-based nanostructures could serve as a safe and self-adjuvanted antigen delivery system for mucosal immunization.

Lung injuries induced by ozone exposure in female mice: Potential roles of the gut and lung microbes

Ozone (O3) is one of the most harmful pollutants affecting health. However, the potential effects of O3 exposure on microbes in the gut-lung axis related to lung injuries remain elusive. In this study, female mice were exposed to 0-, 0.5- and 1-ppm O3 for 28 days, followed by routine blood tests, lung function tests and histopathological examination of the colon, nasal cavity and lung. Mouse faeces and lungs were collected for 16s rRNA sequencing to assess the overall microbiological profile and screen for key differential enriched microbes (DEMs). The key DEMs in faecal samples were Butyricimonas, Rikenellaceae RC9 and Escherichia-Shigella, whereas those in lung samples were DNF00809, Fluviicola, Bryobacter, Family XII AD3011 group, Sharpea, MND1 and unclassified Phycisphaeraceae. After a search in microbe-disease databases, these key DEMs were found to be associated with lung diseases such as lung neoplasms, cystic fibrosis, pneumonia, chronic obstructive pulmonary disease, respiratory distress syndrome and bronchiectasis. Subsequently, we used transcriptomic data from Gene Expression Omnibus (GEO) with exposure conditions similar to those in this study to cross-reference with Comparative Toxicogenomic Database (CTD). Il-6 and Ccl2 were identified as the key causative genes and were validated. The findings of this study suggest that exposure to O3 leads to significant changes in the microbial composition of the gut and lungs. These changes are associated with increased levels of inflammatory factors in the lungs and impaired lung function, resulting in an increased risk of lung disease. Altogether, this study provides novel insights into the role of microbes present in the gut-lung axis in O3 exposure-induced lung injury.

OMIP-099: 31-color spectral flow cytometry panel to investigate the steady-state phenotype of human T cells

We have developed a 31-color panel to define the steady-state phenotype of T cells in human peripheral blood (Table 1). The panel presented here was optimized using cryopreserved peripheral blood mononuclear cells (PBMC). The markers included in this panel were chosen in order to characterize the steady-state phenotype of T cells and includes markers (CD45RA, CD45RO, CCR7, CD95) to distinguish the main subsets (e.g., naïve, TEM , TCM , TEMRA , TSCM etc.) of CD4, CD8, and γδ T cells. This panel also includes markers for the identification of differentiation status (CD27, CD28), activation/antigen experience status (CD11a, CD49d, CD38, HLA-DR, CD56, and CD39), co-inhibitory marker expression (PD-1, TIM-3), and CD4 T helper subsets (CXCR3, CXCR5, CCR4, CCR6, Foxp3, CD25, and CD127). This optimized panel provides a broad assessment of the steady-state phenotype of human T cells.

Enhancement of Microglia Functions by Developed Nano-Immuno-Synergist to Ameliorate Immunodeficiency for Malignant Glioma Treatment

Resident microglia are key factors in mediating immunity against brain tumors, but the microglia in malignant glioma are functionally impaired. Little immunotherapy is explored to restore microglial function against glioma. Herein, oleanolic acid (OA) (microglia "restorer") and D PPA-1 peptide (immune checkpoint blockade) are integrated on a nano-immuno-synergist (D PAM@OA) to work coordinately. The self-assembled OA core is coated with macrophage membrane for efficient blood-brain barrier penetration and microglia targeting, on which D PPA-1 peptide is attached via acid-sensitive bonds for specific release in tumor microenvironment. With the enhanced accumulation of the dual drugs in their respective action sites, D PAM@OA effectively promotes the recruitment and activation of effector T cells by inhibiting aberrant activation of Signal transducer and activator of transcription (STAT-3) pathway in microglia, and assists activated effector T cells in killing tumor cells by blocking elevated immune checkpoint proteins in malignant glioma. Eventually, as adjuvant therapy, the rationally designed nano-immuno-synergist hinders malignant glioma progression and recurrence with or without temozolomide. The work demonstrates the feasibility of a nano-formulation for microglia-based immunotherapy, which may provide a new direction for the treatment of brain tumors.

OMIP-095: 40-Color spectral flow cytometry delineates all major leukocyte populations in murine lymphoid tissues

High-dimensional immunoprofiling is essential for studying host response to immunotherapy, infection, and disease in murine model systems. However, the difficulty of multiparameter panel design combined with a lack of existing murine tools has prevented the comprehensive study of all major leukocyte phenotypes in a single assay. Herein, we present a 40-color flow cytometry panel for deep immunophenotyping of murine lymphoid tissues, including the spleen, blood, Peyer's patches, inguinal lymph nodes, bone marrow, and thymus. This panel uses a robust set of surface markers capable of differentiating leukocyte subsets without the use of intracellular staining, thus allowing for the use of cells in downstream functional experiments or multiomic analyses. Our panel classifies T cells, B cells, natural killer cells, innate lymphoid cells, monocytes, macrophages, dendritic cells, basophils, neutrophils, eosinophils, progenitors, and their functional subsets by using a series of co-stimulatory, checkpoint, activation, migration, and maturation markers. This tool has a multitude of systems immunology applications ranging from serial monitoring of circulating blood signatures to complex endpoint analysis, especially in pre-clinical settings where treatments can modulate leukocyte abundance and/or function. Ultimately, this 40-color panel resolves a diverse array of immune cells on the axes of time, tissue, and treatment, filling the niche for a modern tool dedicated to murine immunophenotyping.

Identification of potential therapeutic drugs targeting core genes for systemic lupus erythematosus (SLE) and coexisting COVID-19: Insights from bioinformatic analyses

OBJECTIVE

Systemic lupus erythematosus (SLE) patients are at risk during the COVID-19 pandemic, yet the underlying molecular mechanisms remain incompletely understood. This study sought to analyze the potential molecular connections between COVID-19 and SLE, employing a bioinformatics approach to identify effective drugs for both conditions.

METHODS

The data sets GSE100163 and GSE183071 were utilized to determine share differentially expressed genes (DEGs). These DEGs were later analyzed by various bioinformatic methods, including functional enrichment, protein-protein interaction (PPI) network analysis, regulatory network construction, and gene-drug interaction construction.

RESULTS

A total of 50 common DEGs were found between COVID-19 and SLE. Gene ontology (GO) functional annotation revealed that "immune response," "innate immune response," "plasma membrane," and "protein binding" were most enriched in. Additionally, the pathways that were enriched include "Th1 and Th2 cell differentiation." The study identified 48 genes/nodes enriched with 292 edges in the PPI network, of which the top 10 hub genes were CD4, IL7R, CD3E, CD5, CD247, KLRB1, CD40LG, CD7, CR2, and GZMK. Furthermore, the study found 48 transcription factors and 8 microRNAs regulating these hub genes. Finally, four drugs namely ibalizumab (targeted to CD4), blinatumomab (targeted to CD3E), muromonab-CD3 (targeted to CD3E), and catumaxomab (targeted to CD3E) were found in gene-drug interaction.

CONCLUSION

Four possible drugs that targeted two specific genes, which may be beneficial for COVID-19 patients with SLE.

Elicitation of T-cell-derived IFN-γ-dependent immunity by highly conserved Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII)

BACKGROUND

Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease has been underestimated. Plasmodium ovale curtisi Duffy binding protein domain region II (PocDBP-RII) is an essential ligand for reticulocyte recognition and host cell invasion by P. ovale curtisi. However, the genomic variation, antigenicity and immunogenicity of PocDBP-RII remain major knowledge gaps.

METHODS

A total of 93 P. ovale curtisi samples were collected from migrant workers who returned to China from 17 countries in Africa between 2012 and 2016. The genetic polymorphism, natural selection and copy number variation (CNV) were investigated by sequencing and real-time PCR. The antigenicity and immunogenicity of the recombinant PocDBP-RII (rPocDBP-RII) protein were further examined, and the humoral and cellular responses of immunized mice were assessed using protein microarrays and flow cytometry.

RESULTS

Efficiently expressed and purified rPocDBP-RII (39 kDa) was successfully used as an antigen for immunization in mice. The haplotype diversity (Hd) of PocDBP-RII gene was 0.105, and the nucleotide diversity index (π) was 0.00011. No increased copy number was found among the collected isolates of P. ovale curtisi. Furthermore, rPocDBP-RII induced persistent antigen-specific antibody production with a serum IgG antibody titer of 1: 16,000. IFN-γ-producing T cells, rather than IL-10-producing cells, were activated in response to the stimulation of rPocDBP-RII. Compared to PBS-immunized mice (negative control), there was a higher percentage of CD4+CD44highCD62L- T cells (effector memory T cells) and CD8+CD44highCD62L+ T cells (central memory T cells) in rPocDBP-RII‑immunized mice.

CONCLUSIONS

PocDBP-RII sequences were highly conserved in clinical isolates of P. ovale curtisi. rPocDBP-RII protein could mediate protective blood-stage immunity through IFN-γ-producing CD4+ and CD8+ T cells and memory T cells, in addition to inducing specific antibodies. Our results suggested that rPocDBP-RII protein has potential as a vaccine candidate to provide assessment and guidance for malaria control and elimination activities.

OMIP-93: A 41-color high parameter panel to characterize various co-inhibitory molecules and their ligands in the lymphoid and myeloid compartment in mice

This 41-color panel has been designed to characterize both the lymphoid and the myeloid compartments in mice. The number of immune cells isolated from organs is often low, whilst an increasing number of factors need to be analyzed to gain a deeper understanding of the complexity of an immune response. With a focus on T cells, their activation and differentiation status, as well as their expression of several co-inhibitory and effector molecules, this panel also allows the analysis of ligands to these co-inhibitory molecules on antigen-presenting cells. This panel enables deep phenotypic characterization of CD4+ and CD8+ T cells, regulatory T cells, γδ T cells, NK T cells, B cells, NK cells, monocytes, macrophages, dendritic cells, and neutrophils. Whilst previous panels have focused on these topics individually, this is the first panel to enable simultaneous analysis of these compartments, thus enabling a comprehensive analysis with a limited number of immune cells/sample size. This panel is designed to analyze and compare the immune response in different mouse models of infectious diseases, but can also be extended to other disease models, for example tumors or autoimmune diseases. Here, we apply this panel to C57BL/6 mice infected with Plasmodium berghei ANKA, a mouse model of cerebral malaria.

Characterization of murine lymphocyte activation and exhaustion markers by a 14-color flow cytometry panel

Previously designed flow cytometry panels have provided a framework to analyze T-cell activation; however, few provide an extensive view of lymphocyte populations, and none are optimized for murine models. This article describes a panel designed specifically to assess the expression of activation and exhaustion markers in expanding lymphocyte populations in tumor-bearing mice across two distinct genetic backgrounds: BALB/c and C57BL/6. This comprehensive panel enables the assessment of multiple functional states and immune checkpoint markers across cytotoxic CD8⁺ T cells, helper and regulatory CD4⁺ T cells and NK cells in murine whole blood, lymph nodes and tumor.

A potential platform of combining sialic acid derivative-modified paclitaxel cationic liposomes with antibody-drug conjugates inspires robust tumor-specific immunological memory in solid tumors

The recent approvals for antibody-drug conjugates (ADCs) in multiple malignancies in the past few years have fueled the ongoing development of this class of drug. However, the limitation of ADCs is selectivity toward cancer cells especially overexpressing the antigen of interest. To broaden the anti-cancer spectrum of ADCs, combinatorial strategies of ADCs with chemotherapy have become a central focus of the current preclinical and clinical research. Here, we used the microtubule stabilizer paclitaxel and enfortumab vedotin-ejfv (EV), an ADC carrying the microtubule inhibitor payload monomethyl auristatin E (MMAE), for co-administration under the consideration of their mechanism of action associated with microtubules. We designed a sialic acid-cholesterol (SA-CH) conjugate-modified cationic liposome platform loaded with PTX (PTX-SAL) for efficiently targeting tumor-associated immune cells. Compared with monotherapy, PTX-SAL-mediated combination therapy with ADCs significantly inhibited S180 tumor growth in mice, with complete tumor regression occurring. The formation of a durable tumor-specific immunological memory response in mice that experienced complete tumor regression was assessed by secondary tumor cell rechallenge, and the production of memory T cells in the spleen was detected as related to the increased CD4⁺T memory cells and the enhanced serum IFN-γ. All our preliminary results throw light on the tremendous application potential for the application of this combination therapy regimen capable of mounting a durable immune response and stimulating a robust T cell-mediated tumor-specific immunological memory.

Improved memory CD8 T cell response to delayed vaccine boost is associated with a distinct molecular signature

Effective secondary response to antigen is a hallmark of immunological memory. However, the extent of memory CD8 T cell response to secondary boost varies at different times after a primary response. Considering the central role of memory CD8 T cells in long-lived protection against viral infections and tumors, a better understanding of the molecular mechanisms underlying the changing responsiveness of these cells to antigenic challenge would be beneficial. We examined here primed CD8 T cell response to boost in a BALB/c mouse model of intramuscular vaccination by priming with HIV-1 gag-encoding Chimpanzee adenovector, and boosting with HIV-1 gag-encoding Modified Vaccinia virus Ankara. We found that boost was more effective at day(d)100 than at d30 post-prime, as evaluated at d45 post-boost by multi-lymphoid organ assessment of gag-specific CD8 T cell frequency, CD62L-expression (as a guide to memory status) and in vivo killing. RNA-sequencing of splenic gag-primed CD8 T cells at d100 revealed a quiescent, but highly responsive signature, that trended toward a central memory (CD62L⁺) phenotype. Interestingly, gag-specific CD8 T cell frequency selectively diminished in the blood at d100, relative to the spleen, lymph nodes and bone marrow. These results open the possibility to modify prime/boost intervals to achieve an improved memory CD8 T cell secondary response.

Biological Effects of Cyclin-Dependent Kinase Inhibitors Ribociclib, Palbociclib and Abemaciclib on Breast Cancer Bone Microenvironment

The CDK4/6 inhibitors (CDKi) palbociclib, ribociclib, and abemaciclib are currently approved in combination with anti-estrogen therapy for the treatment of advanced and/or metastatic hormone receptor-positive/HER2-neu-negative breast cancer patients. Given the high incidence of bone metastases in this population, we investigated and compared the potential effects of palbociclib, ribociclib, and abemaciclib on the breast cancer bone microenvironment. Primary osteoclasts (OCs) and osteoblasts (OBs) were obtained from human monocyte and mesenchymal stem cells, respectively. OC function was evaluated by tartrate-resistant acid phosphatase assay and real-time PCR; OB activity was assessed by an alizarin red assay. OB/breast cancer co-culture models were generated via the seeding of MCF-7 cells on a layer of OBs, and tumor cell proliferation was analyzed using flow cytometry. Here, we showed that ribociclib, palbociclib, and abemaciclib exerted similar inhibitory effects on the OC differentiation and expression of bone resorption markers without affecting OC viability. On the other hand, the three CDKi did not affect the ability of OB to produce bone matrix, even if the higher doses of palbociclib and abemaciclib reduced the OB viability. In OB/MCF-7 co-culture models, palbociclib demonstrated a lower anti-tumor effect than ribociclib and abemaciclib. Overall, our results revealed the direct effects of CDKi on the tumor bone microenvironment, highlighting differences potentially relevant for clinical practice.