Host Immune Response Research Articles

Novel insights into antioxidant status, gene expression, and immunohistochemistry in an animal model infected with camel-derived Trypanosoma evansi and Theileria annulata

Abstract Background Hemoprotozoan diseases, especially trypanosomosis and theileriosis, adversely affect the productivity, growth, and performance of camels. Regular sampling and investigation of camels are challenging due to several factors. Consequently, there is a lack of knowledge on camel parasite genotyping, cytokine production, and oxidative stress parameters during infection. Methods The present study investigated two critical blood protozoa infecting camels in Egypt, Trypanosoma evansi and Theileria annulata, using molecular methods, specifically 18S rRNA gene analysis. Following molecular confirmation, experimental infections were induced in Swiss albino mice to assess the expression of immune response genes and oxidative stress parameters. The study further explored the correlation between histopathological alterations and inflammatory reactions in the kidney, spleen, and liver of infected mice, alongside the immunohistochemical expression of caspase-3, proliferating cell nuclear antigen (PCNA), and tumor necrosis factor (TNF). Results Trypanosoma evansi and T. annulata isolated from naturally infected camels were molecularly identified and deposited in GenBank under accession numbers OR116429 and OR103130, respectively. Infection with T. evansi and T. annulata caused significant adverse effects on the immune condition of infected mice, increasing the pathogenicity of the infection. This was evidenced by a significant increase in oxidative stress parameter levels in both naturally infected camels and experimentally infected mice compared to healthy controls. Furthermore, the expression of immune response genes was significantly elevated in infected mice. Immunohistochemistry analysis showed a pronounced upregulation of caspase-3, PCNA, and TNF in the infected groups relative to the control group. These findings are the first to be reported in Egypt. Conclusions This study successfully identified and genotyped two economically important blood protozoa, T. evansi and T. annulata, from camels in Egypt. Additionally, the experimental animal model provided valuable insights into the immune response, oxidative stress, and histopathological changes induced by these parasites, demonstrating comparable results to naturally infected camels. These findings highlight the potential of this model to study parasite–host interactions and immune responses, contributing to a better understanding of the pathogenic mechanisms of T. evansi and T. annulata infections. This model may be useful for future studies focused on disease control and therapeutic interventions. Graphical Abstract

Abstract C013: Single cell analysis reveals tumor size-driven immune changes in primary breast tumors and corresponding lymph nodes

Abstract Introduction A sentinel lymph node is the primary node draining the tumor and is likely affected early in the metastatic process. The sentinel node holds a key position in the immune response against tumor in breast and represents a unique connection between the tumor and the host immune response. Detection of lymph node metastasis is important for staging a patient’s disease and is closely associated with prognosis. Although the clinical significance is debated, isolated tumor cells (<0.2 mm) appear to have no impact on survival while macro-metastasis (>2 mm) are linked to a poorer prognosis. Alterations in the immune response in lymph nodes with large versus small metastases have been observed, but little is known about the relationship between the immune response in the primary tumor and the metastatic status of the corresponding lymph nodes. Methods We analyzed single-cell suspensions from primary tumors and lymph nodes of 38 patients with early, operable breast cancer enrolled in the OSLO2 clinical observational trial using mass cytometry with a 47- antibody immune panel (including PanKeratin and EpCAM). In total 3.7 million single cells were analyzed and clustered into 40 metaclusters using FlowSOM. A second set of 22 metastatic lymph nodes from the OSLO2 cohort was used to validate results form the metastatic tumor cells. Additionally, immunofluorescence with E-cadherin and PanKeratin was applied, and intensity measured in 4 metastatic lymph nodes and imaging mass-cytometry was applied on one metastatic lymph node Results We found that the immune microenvironment in primary tumor was dominated by CD4 and CD8 T cells, particularly of exhausted and memory phenotype and with a higher frequency of activated regulatory T cells (Treg). In contrast, the immune composition in lymph nodes was predominantly composed of naturally occurring naive B and T cells. Notably, in line with previous publications we observed a skewing towards memory and exhausted phenotype in T cells, along with increased abundance of activated Treg in lymph nodes with larger metastasis to those with smaller or no metastasis. Furthermore, there were no correlation between the immune profile in the primary tumor and corresponding lymph node. The immune profile in the primary tumor was influenced by tumor size, with larger tumors showing a higher frequency of activated Tregs and exhausted CD8 T cells. Furthermore, In situ analysis revealed that the microenvironment in smaller metastase had an mesenchymal phenotype, while larger tumor deposits exhibited a more epithelial-like phenotype. ConclusionThe immune profile of the primary tumor did not predict the immune profile or metastatic status of the corresponding lymph node. Tumor size in both primary tumors and metastatic lymph nodes is the main drivers of changes in immune cell composition. Tumor cells from smaller metastases exhibited an mesenchymal phenotype, while larger metastasis displayed an epithelial phenotype. Citation Format: Inga Hansine H. Rye, Marit Otterlei Fjørtoft, Inger Riise Bergheim, Karin Teien Lande, Kanutte H. Huse, June Helen H. Myklebust, Ole Christian H. Lingjærde, Øystein. Garred, Jon H. Lømo, Hege H. Russnes. Single cell analysis reveals tumor size-driven immune changes in primary breast tumors and corresponding lymph nodes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C013.

Abstract C003: Outer membrane vesicles from Bacteroides fragilis contain coding and non-coding small RNA species that modulate inflammatory signaling in intestinal epithelial cells

Abstract Alterations to the community structure and function of the microbiome are associated with changes to host physiology, including immune responses. However, the contribution of microbial-derived RNAs carried by outer membrane vesicles (OMVs) to host immune responses remains unclear. This paper investigates the role of OMVs and OMV-associated small RNA (sRNA) species from pathogenic and commensal Bacteroides fragilis (ETBF and NTBF respectively) in eliciting different immune responses in intestinal epithelial cells. To distinguish the differences in the sRNA profiles of both strains and their OMVs, small RNA-seq was conducted, and identified enrichment of discrete sRNA species in OMVs that were also differentially expressed between the two strains. To understand the effects of OMVs on pattern recognition receptors, Toll-like receptor (TLR) reporter cells were treated with OMVs, and activation of TLRs 2, 3, 4, and 7 were observed. Treatment of Caco-2 and HT29-MTX cells with OMVs demonstrated increased expression of IL-8. Surprisingly, we discovered that degradation of RNase-accessible RNAs within ETBF OMVs, but not NTBF OMVs, resulted in vesicles with enhanced capacity to stimulate IL-8 expression, indicating that these extravesicular RNAs exert an immunosuppressive effect. This suggests a dual role for OMV-associated RNAs in modulating host immune responses, with implications for both bacterial pathogenesis and therapeutic applications. Citation Format: Aadil Sheikh, Colin Scano, Julia Xu, Tolulope Ojo, Jessica M. Conforti, Kayla L. Haberman, Bryan King, James Lotter, Alysia Martinez, Harry Ojeas, Michelle Pujol, Juli Watkins, Emily Lin, Bernd Zechmann, Amanda Sevcik, Christie Sayes, Elyssia S Gallagher, Joshua Mell, Garth Ehrlich, Joseph H Taube, K. Leigh Greathouse. Outer membrane vesicles from Bacteroides fragilis contain coding and non-coding small RNA species that modulate inflammatory signaling in intestinal epithelial cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C003.

Role of inflammasomes in Toxoplasma and Plasmodium infections.

The detection of pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) by multimeric protein complexes, known as inflammasomes, triggers an inflammatory response, which is a critical component of the innate immune system. This inflammatory response plays a pivotal role in host resistance against parasitic infections, presenting a significant global health challenge. We systematically searched for relevant articles from the Pubmed and the Web of Science database to summarize current insights into how inflammasomes function in preventing infections caused by the apicomplexan parasites Toxoplasma and Plasmodium. In vivo and in vitro studies have extensively explored inflammasomes such as the absent in melanoma 2 (AIM2), NLR family pyrin-containing protein 1 (NLRP1), NLRP3, and NLRP12 inflammasomes, alongside noncanonical inflammasomes, with particular emphasis on the NLRP1 and the NLRP3 inflammasome during Toxoplasma gondii infection or the AIM2 and the NLRP3 inflammasome at various stages of Plasmodium infection. Toxoplasma gondii interacts with inflammasomes to activate or inhibit immune responses. Inflammasomes control parasite burden and parasite-induced cell death, contribute to immune recognition and inflammatory responses and thus influence apicomplexan parasite-associated pathogenesis and the severity of clinical outcomes. Hence, inflammasomes play crucial roles in the progression and outcomes of toxoplasmosis and malaria. A comprehensive understanding of how parasitic infections modulate inflammasome activity enhances insight into host immune responses against parasites.

Giant cerebellar neurocysticercosis masquerading a primary central nervous system neoplasm – A case report with review of literature

Background: Neurocysticercosis (NCC) is one of the leading parasitic infections of the brain. Giant NCC is rare, with only two cases of cerebellar involvement reported till now. In the presence of a host immune response, these giant NCCs can mimic primary central nervous system neoplasms. The objective of this article is to report a rare case of giant cerebellar NCC and its management strategy with a literature review. Case Description: A young male presented with a giant cerebellar ring-enhancing mass with features of raised intracranial pressure, and surgical excision was done. The patient made an uneventful recovery. Conclusion: Surgical excision is safe for NCC, especially in the presence of a diagnostic dilemma.

Therapeutic effect of recombinant Echinococcus granulosus antigen B subunit 2 protein on sepsis in a mouse model.

Sepsis is a potentially fatal systemic inflammatory response syndrome (SIRS) that threatens millions of lives worldwide. Echinococcus granulosus antigen B (EgAgB) is a protein released by the larvae of the tapeworm. This protein has been shown to play an important role in modulating host immune response. In this study we expressed EgAgB as soluble recombinant protein in E.coli (rEgAgB) and explored its protective effect on sepsis. The sepsis model was established by cecal ligation and puncture (CLP) procedure in BALB/c mice. The therapeutic effect of rEgAgB on sepsis was performed by interperitoneally injecting 5µg rEgAgB in mice with CLP-induced sepsis and observing the 72h survival rate after onset of sepsis. The proinflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-6] and regulatory cytokines [IL-10, transforming growth factor beta(TGF-β)] were measured in sera, and the histopathological change was observed in livers, kidneys, and lungs of septic mice treated with rEgAgB compared with untreated mice. The effect of rEgAgB on the macrophage polarization was performed in vitro by incubating rEgAgB with peritoneal macrophages. The levels of TLR2 and MyD88 were measured in these tissues to determine the involvement of TLR-2/MyD88 in the sepsis-induced inflammatory signaling pathway. In vivo, we observed that treatment with rEgAgB significantly increased the survival rate of mice with CLP-induced sepsis up to 72h while all mice without treatment died within the same period. The increased survival was associated with reduced pathological damage in key organs such as liver, lung, and kidneys. It was supported by the reduced proinflammatory cytokine levels and increased regulatory cytokine expression in peripheral blood and key organ tissues. Further study identified that treatment with rEgAgB promoted macrophage polarization from classically activated macrophage (M1) to regulatory M2-like macrophage via inhibiting TLR2/MyD88 signal pathway. The therapeutic effects of rEgAgB on mice with sepsis was observed in a mice model that was associated with reduced inflammatory responses and increased regulatory responses, possibly through inducing polarization of macrophages from proinflammatory M1 to regulatory M2 phenotype through inhibiting TLR2/MyD88 inflammatory pathway.

B2M or CIITA knockdown decreased the alloimmune response of dental pulp stem cells: an in vitro study.

Dental pulp stem cells (DPSCs) have acquired noteworthy attention for their application in treating ischemic diseases and facilitating tissue regeneration. However, the host's immune response following allogenic DPSC transplantation often handicaps the long-term survival of transplanted cells, thereby limiting the application of DPSCs in cell therapy. This study aims to investigate whether genetic modification can alleviate the immunogenicity of DPSCs. Beta 2-microglobulin (B2M) and the class II histocompatibility complex transactivator (CIITA) were individually knocked down in DPSCs by lentiviral particles encoding short hairpin (sh) RNAs. The self-renewal capacity and pluripotency of DPSCs-shB2M (B2M silenced DPSCs) and DPSCs-shCIITA (CIITA silenced DPSCs) were evaluated by CCK8 and differentiation assays including osteogenesis, adipogenesis, and neurogenesis. The expression of HLA-I and HLA-II in DPSCs-shB2M and DPSCs-shCIITA after IFN-γ treatment were analyzed by western blotting, immunofluorescence, and flow cytometry. The function of genetically modified cells was assessed by leukocyte-mediated cytotoxicity and T-cell proliferation assays. Western blotting, immunofluorescence, and flow cytometry revealed that DPSCs-shB2M and DPSCs-shCIITA exhibited impaired IFN-γ inducible HLA-I and HLA-II expression. There were no significant differences in the self-renewal capacity and pluripotency among DPSCs-shB2M, DPSCs-shCIITA, and control groups (p > 0.05). Lower leukocyte-mediated cytotoxicity and higher cell survival rates were found in DPSCs-shB2M and DPSCs-shCIITA groups compared to the control (p < 0.05). T cell proliferation was significantly inhibited in both DPSCs-shB2M and DPSCs-shCIITA groups (p < 0.05). Genetic knockdown of B2M or CIITA in DPSCs substantially reduced their immunogenicity without compromising their stemness, thereby broadening the clinical application of DPSCs in cell therapy and tissue regeneration.

Synthesis, Characterization and Antibacterial Activity Evaluation of CuO NPs and B-CuO NPs Obtained from Livistona Chinensis Leaf Extract.

Nanoparticles (NPs) exhibit fascinating size-dependent chemical and physical characteristics that make them useful for a variety of applications. The present paper reports the green synthesis of CuO NPs and B-doped CuO NPs (B-CuO NPs) from Livistona chinensis leaf extract. Not much work has been reported on the use of the plant extract for the fabrication of NPs, particularly those of Cu and its doped counterparts. Various spectroscopic techniques were used to characterize the synthesized NPs. In the FT-IR spectra, peaks obtained at 504 cm-1 to 600 cm-1 were due to Cu-O vibrations. The energy dispersive X-ray analysis (EDX) spectra confirmed the CuO NPs' composition and B's presence inside the NPs. The peak pattern in the X-ray diffraction (XRD) spectrum confirmed the crystalline and monoclinic phases of the NPs. The average crystalline size of CuO NPs and B-CuO NPs was 19.56 nm and 17.30 nm respectively. The CuO and B-CuO NPs were tested against three Gram-positive bacterial strains namely Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus and three Gram-negative Escherichia coli, Salmonella abony, and Pseudomonas aeruginosa through Agar well diffusion method and it was found that CuO NPs showed higher activity than B-CuO NPs. Gentamicin was used as the positive control. The antibacterial activity may be due to the cell wall disruption by induction of innate and adaptive host immune response, generating toxic reactive oxygen species (ROS), and stimulating intracellular effects.

Inhibiting lipid droplet biogenesis enhances host protection against hypervirulent Klebsiella pneumoniae infections.

Hypervirulent Klebsiella pneumoniae (hvKp), an emerging Kp subtype, has become a serious global pathogen. However, the information regarding host interactions and innate immune responses during hvKp infection is limited. Here, we found that hvKp clinical strains increased triacylglycerol synthesis, resulting in lipid droplets (LDs) formation via the mammalian target of rapamycin signaling pathway in RAW264.7 cells. Treatment with rapamycin, an inhibitor of this pathway, affected LDs formation and antimicrobial responses against clinical hvKp infections. In accordance with the role of LDs in modulating inflammation, the pharmacological inhibition of lipogenesis reduced proinflammatory cytokine expression during hvKp infections. In addition, inhibition of LDs formation using pharmacological inhibitors and knockdown of lipogenesis regulators decreased the intracellular survival of hvKp in macrophages. Moreover, inhibiting LDs biogenesis reduced mortality, weight loss, and bacterial loads in hvKp-infected mice. Collectively, these data suggest that LDs biogenesis is crucial in linking host immune responses to clinical hvKp infections.

Host Innate and Adaptive Immunity Against African Swine Fever Virus Infection

Africa swine fever virus (ASFV) is the causative agent of African swine fever (ASF), a highly contagious hemorrhagic disease that can result in up to 100% lethality in both wild and domestic swine, regardless of breed or age. The ongoing ASF pandemic poses significant threats to the pork industry and food security, with serious implications for the sanitary and socioeconomic system. Due to the limited understanding of ASFV pathogenesis and immune protection mechanisms, there are currently no safe and effective vaccines or specific treatments available, complicating efforts for prevention and control. This review summarizes the current understanding of the intricate interplay between ASFV and the host immune system, encompassing both innate and adaptive immune responses to ASFV infection, as well as insights into ASFV pathogenesis and immunosuppression. We aim to provide comprehensive information to support fundamental research on ASFV, highlighting existing gaps and suggesting future research directions. This work may serve as a theoretical foundation for the rational design of protective vaccines against this devastating viral disease.

Abstract A038: Investigating PD-L1 status in circulating tumor cells isolated from blood samples of lung cancer patients

Abstract Background: This research study aimed to assess the performance of a research use only (RUO) immunofluorescence (IF) assay targeting programmed death-ligand 1 (PD-L1) evolution in epithelial and/or mesenchymal circulating tumor cells (CTCs) isolated from blood using Parsortix® microfluidic technology. Upregulation of PD-L1 enables cancer cells to evade the host immune response. Assessment of PD-L1 status in the tumor, as determined by traditional tissue biopsy, can indicate if immunotherapy has the potential to be an effective treatment. However, PD-L1 expression in tumor biopsies may not reflect metastatic sites in their entirety and can become outdated during tumor evolution, as the process cannot be repeated due its invasive nature. Liquid biopsy offers a minimally invasive option for dynamic testing of PD-L1 in CTCs as patients undergo treatment. Methods: Analytical linearity, and specificity and sensitivity were assessed by spiking HCC1954 and Hs 578T cancer cell lines into the blood samples of 34 healthy volunteers. The assay was then evaluated in samples from 47 metastatic lung cancer patients, among which 32 had a known PD-L1 tissue status (19 positive, 13 negative). Up to six successive draws were taken for each patient, collected into Streck Cell-Free DNA blood collection tubes. ANGLE’s Parsortix® instruments were used to isolate spiked cancer cells or CTCs from blood samples based on their size and deformability. The CTC- enriched harvests were processed onto ANGLE’s CellKeepTM slides and IF stained with ANGLE’s Portrait® PD-L1 RUO assay for PD-L1 identification on CTCs. Slides were imaged on a BioView automated imaging system. Results: Analytical specificity of PD-L1 was 98% and analytical sensitivity was 81%. Analytical linearity (R2=0.91) was shown over a 0–500 cells range. In metastatic lung cancer patients, ≥1 CTC was identified in at least one draw for 91% of donors, with 55% of those donors exhibiting ≥1 PD-L1 positive CTC. A majority (81%) of donors exhibited a positive correlation between PD-L1 tissue status and CTC expression. However, the remaining 19% of donors exhibited discordance with a PD-L1 negative tissue status but PD-L1 positivity identified in ≥1 CTC. Of the PD-L1 positive CTCs identified, 98% expressed mesenchymal markers. Dynamic change was shown in all but one donor, with PD-L1 status of the CTCs changing over time. Conclusions: This study demonstrated the ability to determine PD-L1 status in CTCs from the blood of metastatic lung cancer patients and, subject to further study, the future potential to develop dynamic PD-L1 testing for advancement of more personalized cancer treatments. Patients with a PD-L1 negative tissue status exhibited PD-L1 positive CTCs, demonstrating the feasibility of a more repeatable and accurate assessment of PD-L1 status than can be achieved through a traditional tissue biopsy. Citation Format: Morgan Spode, Chloe Goodwin, Aarabhi Varatharajah, Aaron Cottingham, Elisha Duhig, Laura Kaja, David Greaves, Mariacristina Ciccioli, Anne-Sophie Pailhes-Jimenez. Investigating PD-L1 status in circulating tumor cells isolated from blood samples of lung cancer patients [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A038.

Unveiling the hidden arsenal: new insights into Proteus mirabilis virulence in UTIs

Proteus mirabilis is a Gram-negative bacterium commonly found in urinary tract infections (UTIs) and catheter-associated urinary tract infections (CAUTIs). The pathogenic mechanisms of Proteus mirabilis are complex and diverse, involving various virulence factors, including fimbriae, flagella, urease, polyphosphate kinase, lipopolysaccharides, cyclic AMP receptor protein, Sigma factor RpoE, and RNA chaperone protein Hfq. These factors play crucial roles in bacterial colonization, invasion, evasion of host immune responses, biofilm formation, and urinary stone formation. This paper is the first to comprehensively describe the hydrogenase system, autotransporter proteins, molybdate-binding protein ModA, and two-component systems as virulence factors in Proteus mirabilis, providing new insights into its pathogenic mechanisms in urinary tract infections. This review explores the mechanisms of biofilm formation by Proteus mirabilis and the various virulence factors involved in UTIs, revealing many newly discovered virulence factors from recent studies. These findings may offer new targets for clinical treatment of UTIs and vaccine development, highlighting the importance of understanding these virulence factors.

The role of AIM2 in inflammation and tumors

Absent in melanoma 2 (AIM2) serves as an intracellular nucleic acid sensor that predominantly detects double-stranded DNA (dsDNA) within the cells. This detection initiates the assembly of inflammasome and activates the inflammasome signaling cascade, resulting in the production of inflammatory mediators and the cleavage of Gasdermins. Consequently, these processes culminate in inflammatory responses and pyroptotic cell death. AIM2 plays a pivotal role in modulating inflammation and tumorigenesis, functioning through both inflammasome-dependent and independent mechanisms. Its influence on the host immune response is dual-faceted, exhibiting both promotive and inhibitory effects in the contexts of inflammation and tumors. These effects are predominantly contingent upon the specific cell type expressing AIM2 and the nature of the host’s disease. This article seeks to review the latest advancements in understanding the cell-specific functions of AIM2 in inflammation and tumorigenesis, with the objective of offering insights for further research on AIM2 and informing the development of targeted therapeutic strategies for clinical application.

Assessment of Babesia ovis pathogenicity in goats: implications for transmission dynamics and host resistant

Babesia ovis, commonly associated with ovine babesiosis, poses a significant threat to sheep health, often resulting in severe clinical manifestations and high mortality rates. However, the impact of B. ovis on goats has remained uncertain, prompting us to investigate its pathogenicity in caprine hosts. Experimental infections using B. ovis-infected blood inoculation and infected tick infestation, were conducted on spleen-intact (n=5) and splenectomized (n=5) goats. The experimental infection was performed using fresh blood obtained from a B. ovis-infected splenectomized sheep. One spleen-intact sheep served as a control for the experimental infection with B. ovis-infected Rhipicephalus bursa ticks. While all experimentally infected sheep (#501, #575) displayed severe clinical symptoms and high parasitemia, goats exhibited resistance, showing no significant clinical manifestations or sustained parasitemia. Notably, B. ovis was detected in two spleen-intact goats via nested PCR, prompting further investigation into their role as reservoirs for tick-borne transmission. These goats were then infested with Babesia spp.-free R. bursa larvae (0.1 gr) and adults (50 females and 50 males) for transstadial and transovarial transmission experiments respectively. Results indicated that chronically B. ovis-infected spleen-intact goats are not significant sources for maintaining the tick-borne transmission cycle of the parasite. These findings highlight the differential susceptibility of goats to B. ovis infection compared to sheep and their limited role as reservoirs for parasite transmission. Understanding the role of goats in B. ovis transmission and their resistance mechanisms can inform effective control measures and reduce economic losses in affected regions. Further research into caprine babesiosis and host immunological responses is essential to fully elucidate their possible role as reservoirs of the parasite, and underlying mechanisms of host susceptibility and parasite pathogenesis.

Analysis of the serum proteome profile of wild stump-tailed macaques (Macaca arctoides) seropositive for Zika virus antibodies in Thailand

Zika virus (ZIKV) is a member of the Flaviviridae virus family and poses a significant global health concern. ZIKV is transmitted by Aedes mosquitoes, and it has been implicated in various neurological conditions associated with fetal brain development. ZIKV has two transmission cycles: a sylvatic cycle in which nonhuman primates are infected via arboreal mosquito bites, and an interhuman (urban) cycle in which the virus is transmitted among primates by Aedes mosquitoes. ZIKV was first discovered in wild macaques, and the danger posed by the virus is increased due to the close proximity between humans and wild animals in modern society. However, data regarding the extent and role of infection in nonhuman primates are limited. Thus, there is an urgent need for improved surveillance, diagnostic methods, and public health interventions to effectively combat ZIKV transmission and its associated health impacts in Southeast Asia. In this study, we used a proteomics and bioinformatics approach to profile serum proteins in wild stump-tailed macaques seropositive for neutralizing antibodies against ZIKV. A total of 9,532 total proteins were identified, and 338 differentially expressed proteins were identified between naïve and seropositive animals. A total of 52 important proteins were used to construct a serum proteomic profile. These 52 important proteins were associated with immune and inflammatory responses (36.54%), neurological damage (23.08%), viral activities (21.15%), the apoptosis signaling pathway (9.61%), and other pathways (9.61%). Our proteomic profile identified proteins that inhibit the apoptosis pathway, intracellular resource competition with the virus, and neurological damage due to ZIKV and the host immune and defense responses.

'Re-Wilding' an Animal Model With Microbiota Shifts Immunity and Stress Gene Expression During Infection.

The frequency of emerging disease is growing with ongoing human activity facilitating new host-pathogen interactions. Novel infection outcomes can also be shaped by the host microbiota. Caenorhabditis elegans nematodes experimentally colonised by a wild microbiota community and infected by the widespread animal pathogen, Staphylococcus aureus, have been shown to suffer higher mortality than those infected by the pathogen alone. Understanding the host responses to such microbiota-pathogen ecological interactions is key to pinpointing the mechanism underlying severe infection outcomes. We conducted transcriptomic analyses of C. elegans colonised by its native microbiota, S. aureus and both in combination. Correlations between altered collagen gene expression and heightened mortality in co-colonised hosts suggest the microbiota modified host resistance to infection. Furthermore, microbiota colonised hosts showed increased expression of immunity genes and variable expression of stress response genes during infection. Changes in host immunity and stress response could encompass both causes and effects of severe infection outcomes. 'Re-wilding' this model nematode host with its native microbiota indicated that typically commensal microbes can mediate molecular changes in the host that are costly when challenged by a novel emerging pathogen.

ApoEVs Transfer Mitochondrial Component to Modulate Macrophages in Periodontal Regeneration.

Macrophages are key players in the host immune response to periodontal pathogens and tissue repair. The aim of this study was to explore the potential of apoptotic cell-derived extracellular vesicles (ApoEVs) in modulating the mitochondrial function of macrophages as a mean to enhance periodontal tissue regeneration. ApoEVs were extracted from periodontal ligament stem cells (PDLSCs) and characterized to observe their effects on macrophage function. Invivo experiments, ApoEVs were mixed with hyaluronic acid and injected into the periodontal pockets of rats with periodontitis to observe their impact on periodontal tissue regeneration and the immune microenvironment. Functional assays were conducted to confirm whether ApoEVs contained mitochondrial components and which specific components were transferred to regulate macrophage function. The experimental findings showed that treatment of ApoEVs efficiently restored the homeostasis of macrophage and improved tissue regeneration in a periodontitis rat model. Mechanism investigation demonstrated that the efferocytosis of ApoEVs resulted in the transfer of mitochondrial components from PDLSCs to macrophage. The increased mitochondrial components within macrophages improved mitochondrial function and polarization of macrophages towards the anti-inflammatory M2 phenotype, resulting in the improvement of inflammatory environment in periodontal tissues. ApoEVs can transfer mtDNA to enhance mitochondrial function in macrophages, fostering their transition to an anti-inflammatory phenotype. Ultimately, this process improves the immune microenvironment in periodontitis and promotes periodontal tissue regeneration.

Molecular characterization of Ebola virus, immune response, and therapeutic challenges: a narrative review

AbstractThe Ebola virus (EBOV) remains a major public health challenge due to its complex structure and the lack of appropriate and effective vaccines and therapies. This review characterizes the Ebola virus, its immune response, and its therapeutic challenges. Structural EBOV proteins include the envelope glycoprotein, nucleoprotein, RNA polymerase L, and viral proteins VP30, VP24, VP35, and VP40. The proteins play a role in the virus’s pathogenesis by evading the host's immune response. The immune system evasion mechanisms of EBOV are critical in its pathogenesis. Some vaccines, such as the recombinant vesicular stomatitis virus-Zaire Ebola virus (RVSV-ZEBOV), have proven to be very effective and have been approved by the Food and Drug Administration (FDA) additionally, four other vaccines have been approved including Gam Evac-Combi (licensed in Russia), ad5-EBOV (approved in China), Zabdeno and Mvabea (approved in Europe). However, some challenges remain in developing effective vaccines, such as the selection of immunogens, cross-protecting immunity, long-term protection, mechanism of protection, and rapid response vaccination. Despite the progress made, there is still a need for an effective vaccine that offers durable and broad protection against multiple strains of the Ebola virus. This will be achieved through the collaboration of various organizations and government and Non-Governmental Organization (NGO) agencies.

Advances in research on the role of high carbohydrate diet in the process of inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is a chronic, systemic gastrointestinal disorder characterized by episodic inflammation that requires life-long management. Although the etiology of IBD is not fully understood, it is hypothesized to involve a multifaceted interplay among genetic susceptibility, the host immune response, and environmental factors. Previous studies have largely concluded that IBD is associated with this complex interplay; however, more recent evidence underscores the significant role of dietary habits as risk factors for the development of IBD. In this review, we review the molecular mechanisms of high-sugar and high-fat diets in the progression of IBD and specifically address the impacts of these diets on the gut microbiome, immune system regulation, and integrity of the intestinal barrier, thereby highlighting their roles in the pathogenesis and exacerbation of IBD.

Distinct neutrophil effector functions in response to different isolates of Leishmania aethiopica.

In Ethiopia, cutaneous leishmaniasis is mainly caused by Leishmania (L.) aethiopica parasites and presents in three main clinical forms. It is still not clear if the host immune response plays a role in the development of these different presentations. Since neutrophils are likely to be one of the first immune cells present at the site of the sand fly bite, we set up an in vitro model of infection of neutrophils with L. aethiopica and assessed some of the main neutrophil effector functions: association with and internalisation of parasites, apoptosis and ROS production. We used three freshly isolated clinical isolates and one isolate that has been kept in culture for decades. Our results showed by flow cytometry that all four L. aethiopica isolates had the ability to associate with neutrophils. The three clinical isolates of L. aethiopica associated more efficiently with neutrophils than the long-term cultured L. aethiopica. At 18h, two distinct populations of neutrophils were identified that associated with L. aethiopica, CD15high and CD15low neutrophils. Confocal microscopy demonstrated that all isolates can be internalised. Our results also showed that all parasites induced apoptosis in L. aethiopica-associated neutrophils. Moreover, our results showed that after 2h, L. aethiopica-associated neutrophils upregulated their production of ROS, but to a greater extent with the long-term cultured L. aethiopica. After 18h of incubation, CD15lowparasite+ showed an impaired ability to produce ROS compared to CD15highparasite+. Using this in vitro model, our results show that different L. aethiopica parasite isolates, most notably long-term cultured parasites, had differential effects on neutrophil effector functions.