Disseminated acanthamoebiasis is a rare but severe opportunistic infection that can involve multiple organs, including the liver, causing fatal outcomes. This study provides new insights into hepatic pathogenesis and possible relationship with angiogenesis activity and the therapeutic role of quercetin conjugated silver nanoparticles (Q-AgNPs). Sixty BALB/c mice were divided into four groups: uninfected control, uninfected treated with Q-AgNPs, infected group and infected treated with Q-AgNPs. The Q-AgNPs were synthesised and characterised by spectrophotometry, electron microscope, zeta potential and dynamic light scattering. Hepatic tissues were examined histopathologically for granulomas (classified as caseating/non-caseating and immature/mature) and vascular changes. Hypoglycaemia and expression of angiogenic markers (CD31, CD34 and MMP9) were assessed. Acanthamoeba polyphaga infection induced significant hepatic granulomatous inflammation, hypoglycaemia, vascular remodelling and upregulation of CD31, CD34 and MMP9, indicating active angiogenesis. Granulomas exhibited necrotic cores in some cases and progressed from immature to mature stages. Q-AgNPs treatment markedly attenuated granuloma numbers, suppressing angiogenic marker expression, mitigating inflammation, capillary permeability and liver lesions. This study provides novel evidence linking Acanthamoeba infection to hepatic granuloma formation and angiogenesis-driven pathology which may serve as useful biomarkers for extracerebral acanthamoebiasis. Further studies are needed to evaluate long-term outcomes and host-parasite interaction.
Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) peptide accumulation and tau protein-mediated neurodegeneration, and neuroinflammation is increasingly recognized as a major process associated with tau pathology. Chronic Toxoplasma gondii infection reduces amyloid accumulation in AD models through immune modulation, but its stage-specific associations with tau-related pathology remain unclear. Here, we investigated how chronic T. gondii infection is associated with tau-related molecular and neuropathological changes in the 5XFAD AD mouse model. At 40 weeks post-infection, we profiled transcriptomic changes and evaluated Aβ-associated (21 genes), Aβ/tau-shared (22 genes), and tau-associated (21 genes) pathological programs together with p-tau immunoreactivity in brain sections. Chronic infection was associated with selective modulation of molecular networks linked to neuroimmune signalling and tau-related pathways rather than broad suppression of AD-related gene expression. Among tau-related pathological stages, the neuroinflammation-related amplification module linking Aβ and tau exhibited the most prominent transcriptomic change in T. gondii-infected AD mice, whereas upstream kinase-related initiation pathways and downstream toxin conversion or accumulation-related processes changed relatively minimally. These transcriptomic changes were accompanied by a marked reduction in phosphorylated tau load at the tissue level. Collectively, these findings suggest that chronic T. gondii infection is associated with selective modulation of tau-related pathogenic programs and reduced p-tau burden in the 5XFAD brain.
Human babesiosis is an emerging disease in North America caused by the red blood cell (RBC)-infecting parasite Babesia microti. Despite a rise in clinical cases in recent years, the pathogenesis and host immune response to B. microti infection remain unclear. CD47 is a 'marker of self' transmembrane glycoprotein expressed on cell membranes that inhibits phagocytosis through interactions with macrophage signal-regulatory protein alpha (SIRPα). We posit that disruption of CD47-SIRPα signalling will induce macrophage uptake of Babesia-infected RBCs and reduce parasitaemia in susceptible hosts. To evaluate this, we compared the in vivo clearance of B. microti in CD47 knockout (CD47-/-) mice and wild-type C57BL/6J mice. Our results showed pronounced differences in infection kinetics between the two mouse strains. C57BL/6J mice showed steadily increasing parasitaemia that peaked at an average of 12%, whereas CD47-/- mice exhibited parasitaemia that never exceeded 1.5% throughout infection. Parasitaemia became undetectable by Day 21 in C57BL/6J and by Day 16 in CD47-/- mice, indicating resolution of infection. These results imply that, in the absence of CD47, growth of B. microti is diminished due to more efficient phagocytosis of infected RBCs by macrophages. We propose that CD47-SIRPα signalling plays a key role in the innate response to Babesia and suggest CD47 modulation as a new therapeutic target for the treatment of babesiosis.
ABSTRACT The blood‐stage merozoite surface protein 1 ( Pv MSP 19 ) of Plasmodium vivax is a key target of naturally acquired antibodies. Effective humoral responses depend on T‐cell co‐stimulation, notably via the inducible co‐stimulator (ICOS) molecule. Polymorphisms in the ICOS gene may influence antibody production, yet this relationship remains unexplored in naturally infected populations. We analysed 91 individuals with uncomplicated P. vivax infection in Venezuela. Total IgG antibodies against recombinant Pv MSP 19 were measured by ELISA. A two‐step cluster analysis based on antibody reactivity indices (RI) was employed to categorize participants as low, medium, or high responders. Genotyping of ICOS polymorphisms (rs4404254, rs4675379 and rs10183087) was performed using PCR‐based methods. Haplotype frequencies (inferred via the Expectation–Maximization algorithm), linkage disequilibrium (LD) and associations under various genetic inheritance models were assessed using Haplo.stats (R environment) and SNPStats. Pv MSP 19 ‐specific IgG was detected in 70.3% of participants. The optimal three‐cluster solution (silhouette coefficient = 0.7) revealed significant differences in median RI across low (0.408), medium (0.862) and high responders (1.267; p < 0.001). ICOS genotypes and haplotypes showed no significant associations with antibody levels across any inheritance models, although strong LD was observed among the three loci ( p < 0.05). Notably, antibody responses positively correlated with the number of prior malarial episodes ( r = 0.803, p < 0.0001). Our results indicate that the studied ICOS polymorphisms do not significantly affect IgG responses against Pv MSP 19 in this population, suggesting that variability in other costimulatory molecules may more strongly influence humoral immunity to P. vivax . These findings highlight the complexity of T‐cell‐mediated regulation of antibody responses and provide insights for optimizing vaccine strategies targeting blood‐stage malaria antigens.
Infection with the intracellular apicomplexan parasite Toxoplasma gondii causes severe and often fatal clinical outcomes worldwide, especially in patients with immunodeficiency, diabetes and in pregnant women and infants. Despite approximately one-third of the global population being infected with T. gondii, there is currently no effective vaccine available for humans. The objective was to develop a potential vaccine candidate for T. gondii, which would incorporate the B- and T-lymphocyte epitopes derived from three immunogenic antigens of the parasite. Initially, the immunodominant epitopes present in the SAG1, GRA6 and GRA7 proteins of T. gondii were identified. Following this, a multi-epitope vaccine was developed by integrating B-cell epitopes, CTL epitopes and HTL epitopes, with the addition of the 50S ribosomal protein L7/L12 serving as an adjuvant to enhance the immunogenic properties of the vaccine. All identified epitopes demonstrated characteristics of being antigenic, nonallergenic, nontoxic and lacking human homologues. Furthermore, the candidate vaccine exhibited immunogenicity, non-allergenicity and stability. Molecular docking studies indicated robust interactions between the vaccine construct and the TLR-4 immune receptor. Additionally, the stability of the formulated vaccine was confirmed through molecular dynamic simulations. In silico analyses suggested that the vaccine construct could effectively initiate primary immune responses; however, further laboratory evaluations are required to verify its efficacy and safety.
Schistosomiasis, or bilharzia, is a highly prevalent water-borne helminth infection that accounts for an estimated 1.5-1.7 billion disability-adjusted life years lost annually. Pathology driven by adult worms and eggs is accompanied by robust immunomodulation in the human host. Protective responses may promote worm elimination, limit bystander tissue injury caused by parasite migration and contain eggs within granulomatous lesions. However, evidence also suggests that schistosomes can actively or indirectly influence haematopoiesis, thereby reshaping downstream mature immune cell responses. This perspective reviews current literature on schistosome-dependent and host-derived regulation of haematopoiesis, the importance of preclinical modelling and the emerging relevance of controlled human challenge models. It also discusses bone marrow organoid models and their utility for recapitulating complex infection dynamics, with the aim of informing clinically relevant studies and therapeutic strategies.
γδT cells are a subset of innate lymphocytes that play an essential role in anti-infection immunity. However, the functional role of CD8αβ+ γδT cells, a distinct subset of γδT cells, remains poorly characterized during malaria infection. Female C57BL/6 mice were intraperitoneally injected with 1 × 106 Plasmodium yoelii-infected red blood cells (iRBCs). At 12 days post-infection (12 dpi, the peak of parasitemia), spleens were harvested and lymphocytes were isolated. Fluorescence-activated cell sorting (FACS) was performed to determine the frequency, phenotypic features and functional properties of CD8αβ+ γδT cells. Meanwhile, CD45+ lymphocytes were sorted for single-cell RNA sequencing (scRNA-seq) to compare differentially expressed genes between CD8αβ+ γδT and CD8αα+ γδT cell subsets. FACS analysis revealed a significant increase in CD8αβ+ γδT cells following P. yoelii infection. These cells exhibited elevated expression of activation-related molecules, enhanced effector functions, preferential polarization towards an IFN-γ-producing (γδT1) phenotype, and reduced expression of exhaustion markers. scRNA-seq further demonstrated that CD8αβ+ γδT cells upregulated genes involved in DNA replication and repair. Our findings indicate that CD8αβ+ γδT cells upregulate molecules associated with activation and function during P. yoelii infection, suggesting that they may play a more prominent role in host defence against malaria.
Visceral leishmaniasis (VL) is a chronic systemic disease that, without proper treatment, can be fatal. Extracellular vesicles released by Leishmania species (Leish-EVs) perform various functions, including modulation of the host's immune system and inflammatory responses. This study investigated whether Leish-EVs produced by circulating strains of Leishmania (Leishmania) infantum exhibited the same pattern of cytokine stimulation and modulation of inflammatory and pro-inflammatory responses as those produced by a standard strain maintained for many years in different laboratories. The assays were performed using Leish-EVs released by promastigotes of the two L. (L.) infantum strains. The Standard strain was L. (L.) infantum (MHOM/BR/1972/LD), maintained under laboratory conditions, while the Natural strain was L. (L.) infantum recently isolated from a dog living in an endemic region of São Paulo State, Brazil. Both strains were cultivated in 199 medium and, during the logarithmic growth phase, promastigotes were prepared for excretion of Leish-EVs according to previously established protocols. The Natural strain, when compared with the Standard strain, produced a higher concentration of Leish-EVs, which stimulated THP-1 cells to release large amounts of THP-1-EVs (EVs produced by THP-1 cells). In addition, stimulation of THP-1 cells with Leish-EVs induced high expression of miR-21-5p and miR-146a-5p, as well as cytokines IL-10, IL-12, and particularly TGF-β. These findings suggest that Leish-EVs released by strains living in nature have greater immunomodulatory potential than those produced by strains maintained in laboratories, impacting both miRNA regulation and cytokine expression.
This study aimed to investigate the role of interleukin (IL)-25 in the pathogenesis of angiostrongylosis. We used ICR mice as non-permissive hosts, divided them into groups and experimentally infected them with infective larvae of the Angiostrongylus cantonensis. Two groups of infected mice were injected intraperitoneally with either mouse IL-25 or an anti-IL-25 monoclonal antibody (mAb) at 3 days post-infection (dpi), followed by booster injections at the same dose every 5 days. Serum samples and brain tissues were collected weekly from each group for immunological and pathological examinations. The IL-25-treated group exhibited significant increases in eosinophil percentages and levels of immunoglobulin E (IgE), as well as in the levels of IL-5 and IL-13. The severity of eosinophilic meningitis was exacerbated in the IL-25-treated group 21 dpi. These results suggest that IL-25 may enhance eosinophil-associated inflammation in mice infected with A. cantonensis.
Gastrointestinal parasitic infections are considered a significant public health concern with widespread global prevalence. The pathological processes arising from these infections contribute to numerous public health challenges, particularly in tropical and subtropical regions. Prevention and management primarily rely on the administration of anthelmintic and antiprotozoal drugs; however, the growing prevalence of drug resistance poses a major obstacle to the complete eradication of parasitic infections in both humans and livestock. This highlights the need for exploring alternative strategies. The use of beneficial microorganisms, particularly probiotics and their metabolites (known as postbiotics), has gained significant interest due to their potential prophylactic benefits against various diseases, including parasitic infections. Recent research on the interactions between postbiotics, parasites, and host immune cells through both animal models and in vitro culture systems has seen substantial growth. Postbiotics exert antiparasitic effects through multiple mechanisms, including disruption of parasite membrane integrity, inhibition of key metabolic enzymes, induction of oxidative stress, interference with attachment and invasion, modulation of host immune responses, and alteration of the intestinal microenvironment to hinder parasite survival. This review will focus on the effects of postbiotics and their mechanisms of action against helminths and protozoan parasites, both of which are relevant to gastrointestinal health.
The blood-stage merozoite surface protein 1 (PvMSP19) of Plasmodium vivax is a key target of naturally acquired antibodies. Effective humoral responses depend on T-cell co-stimulation, notably via the inducible co-stimulator (ICOS) molecule. Polymorphisms in the ICOS gene may influence antibody production, yet this relationship remains unexplored in naturally infected populations. We analysed 91 individuals with uncomplicated P. vivax infection in Venezuela. Total IgG antibodies against recombinant PvMSP19 were measured by ELISA. A two-step cluster analysis based on antibody reactivity indices (RI) was employed to categorize participants as low, medium, or high responders. Genotyping of ICOS polymorphisms (rs4404254, rs4675379 and rs10183087) was performed using PCR-based methods. Haplotype frequencies (inferred via the Expectation-Maximization algorithm), linkage disequilibrium (LD) and associations under various genetic inheritance models were assessed using Haplo.stats (R environment) and SNPStats. PvMSP19-specific IgG was detected in 70.3% of participants. The optimal three-cluster solution (silhouette coefficient = 0.7) revealed significant differences in median RI across low (0.408), medium (0.862) and high responders (1.267; p < 0.001). ICOS genotypes and haplotypes showed no significant associations with antibody levels across any inheritance models, although strong LD was observed among the three loci (p < 0.05). Notably, antibody responses positively correlated with the number of prior malarial episodes (r = 0.803, p < 0.0001). Our results indicate that the studied ICOS polymorphisms do not significantly affect IgG responses against PvMSP19 in this population, suggesting that variability in other costimulatory molecules may more strongly influence humoral immunity to P. vivax. These findings highlight the complexity of T-cell-mediated regulation of antibody responses and provide insights for optimizing vaccine strategies targeting blood-stage malaria antigens.
Trypanosoma cruzi infection, which causes Chagas' disease, induces an immune response in the host whose efficiency is important for the infection to persist or be eliminated. Alcohol consumption produces a great impact on the immune system, inducing alterations in the determination of T lymphocyte effector function, directing the profile of these cells to tolerance or inflammation. Our study aimed to evaluate, in C57BL/6 mice, the cytokine production in splenic leukocytes from T. cruzi infected and treated (EtOH) for 15 days and controls. Twenty-four mice were randomised into four groups, with 12 animals each: (1) Non-Infected Control (NI), (2) Control Infected (CI), (3) Experimental Non-Infected (EtOH-NI), and (4) Experimental Infected (EtOH-I). Ethanol-pre-exposed infected mice exhibited elevated parasitaemia during the patent period compared to controls. Adaptive immunity was characterised by increased IL-4, IL-10 and IFN-γ production by CD8+ T lymphocytes, while innate immunity showed reduced cytokine production, particularly in NK cells and macrophages. Ethanol amplified IL-10 and IFN-γ responses in macrophages yet suppressed TNF-α production in dendritic cells and macrophages during infection. These findings suggest ethanol modulates the immune response by enhancing adaptive immunity while impairing innate mechanisms, contributing to altered host-pathogen dynamics in T. cruzi infection.
HIV-associated Immune Reconstitution Inflammatory Syndrome (IRIS) may significantly alter the immunopathological presentation of American Tegumentary Leishmaniasis (ATL), occasionally causing paradoxical clinical exacerbations. We report the long-term follow-up of a 39-year-old female coinfected with HIV and disseminated mucocutaneous leishmaniasis caused by Leishmania (Viannia) sp., who experienced severe lesion exacerbation four months after initiating High-Activity Antiretroviral Therapy (HAART). Despite successful viral suppression and CD4+ T-cell recovery, she developed aggressive mucocutaneous plaques with nasal septum destruction. Immunohistochemical analysis of a skin biopsy revealed a profile distinct from HIV-negative ATL controls: classic pro-inflammatory markers (CD68, iNOS, IL-6, and IL-17) were markedly suppressed, while CD163, IL-10, TGF-β and IL-18 were elevated, signalling M2 macrophage activation and paradoxical Th2 polarisation. CD8+ T cells were the most preserved lymphocyte subset, which is consistent with their reported cytotoxic, tissue-damaging role in mucosal leishmaniasis caused by L. (Viannia) braziliensis. Standard pentavalent antimonial combined with sustained HAART led to complete resolution without recurrence over 16 years. This case illustrates how IRIS may be associated with atypical Th2-polarised pathology and CD8-mediated tissue injury in ATL, highlighting the need for awareness of this presentation in coinfected patients from endemic areas.
The thymus is a vital organ for T-cell development that undergoes significant changes during malaria infection, including atrophy and disrupted structure, which weaken immune responses. This study examines the mechanisms behind thymic atrophy during Plasmodium chabaudi AS infection, focusing on cellular and molecular changes across different parasitemia stages. Our results show that thymic atrophy is marked by a substantial decrease in thymus weight and cellularity, especially at 20%-30% parasitemia levels. A significant loss of DP and SP thymocytes mainly causes this atrophy. Histological analysis revealed notable cortical shrinkage and DNA fragmentation in thymic cells, indicating increased apoptosis. Elevated serum cytokines and chemokines, including IFN-γ, TNF-α, IL-6 and CXCL9, were observed throughout the infection, with higher levels correlating with the degree of thymic atrophy. Also, early release of thymocytes into peripheral tissues, especially the spleen, worsened the decrease in thymic cellularity. However, after parasitemia resolved, the thymus recovered, restoring its structure and thymocyte populations. These results highlight the complex interaction between parasite-induced inflammation and immune cell behaviour, suggesting that even though P. c. chabaudi AS infection is not lethal, a prolonged parasitic burden can cause severe thymic dysfunction, possibly impairing immune system function.
Toxocara canis is the most prevalent intestinal roundworm of dogs and other canids, with significant zoonotic potential for humans. In the present study, two recombinant antigens, rTc-CTL-1 and rTES-120, were developed from the larvae of T. canis excretory-secretory (TES) antigens by amplifying, cloning and expressing the respective genes in Escherichia coli. The native TES antigen was prepared from in vitro cultivation of larvae. A total of 170 serum samples were collected from dogs above 6 months of age (n = 90) and below 6 months of age (n = 80) in the Chennai region, Tamil Nadu. The serodiagnostic potential of the recombinant rTc-CTL-1 and rTES-120 antigens was compared with that of the native TES antigen using ELISA for the detection of anti-Toxocara IgG antibodies. The rTc-CTL-1 antigen-based ELISA showed that 40% of dogs above 6 months and 28.8% of dogs below 6 months were positive, whereas the rTES-120 antigen detected 35.6% and 22.5% positivity in the respective age groups. In comparison, the native TES antigen-based ELISA detected 58.9% positivity in dogs above 6 months and 38.8% in dogs below 6 months of age. Among the three antigens, the highest percentage of seropositivity as well as the highest antibody titre was detected with the native TES antigen, followed by the recombinant rTc-CTL-1 antigen and the lowest with the TES-120 antigen. Statistical analysis showed a highly significant difference in seropositivity between the recombinant and native TES antigens (χ2 = 15.52, p < 0.01), while no significant difference was observed between the recombinant antigens (χ2 = 1.09, p > 0.05). However, a highly significant difference was observed between the age groups of dogs when using the native TES antigen (χ2 = 6.87, p < 0.01). Detection of T. canis eggs in faecal samples revealed that only 12.2% of adult dogs were positive, whereas 60% of pups were positive. In contrast, the IgG ELISA test detected more positive cases in adult dogs compared to faecal examination. It was concluded that the IgG-based ELISA using either recombinant or native TES antigens is a reliable tool for detecting migratory larval infection in adult dogs, with a fairly high degree of sensitivity.
Robust T helper 1 (Th1) cell responses, which activate macrophages to kill intracellular parasites, are required to control Leishmania infection. Yet, visceral leishmaniasis (VL) patients do not control the infection despite the expansion of CD4+ T cells and increased IFN-γ expression in the spleen. Chemokines and/or chemokine receptors are involved in cellular migration and are critical in the inflammatory response. In a recent study that defined a transcriptional signature for CD4+ T cells from active VL patients, we found several differentially expressed chemokine receptor genes in CD4+ T cells compared to healthy endemic controls (EC). Since CD4+ T cells play crucial roles in parasite clearance, a better understanding of the role of altered chemokine receptor expression on CD4+ T cells and their different subsets during VL could inform future treatment strategies. In this study, we examined the gene expression and surface protein expression of differentially expressed chemokine receptors found in human VL subjects, relative to endemic controls (EC) by real-time qPCR and multicolor flow cytometry, respectively. We measured chemokine levels in plasma by enzyme-linked immunosorbent assay (ELISA) and performed transwell migration assays and flow cytometry to measure the migratory potential of CD4+ T cell subsets. We found elevated mRNA and surface protein expression of CCR5, while reduced CCR4 and CCR6 expression in CD4+ T cells from VL patients compared to EC. The frequency of CCR5 expressing Th1 cells was increased in peripheral blood, indicating the expansion of CCR5+ Th1 cells that may be responsible for Th1 cells trafficking towards infected tissues. Lower CCR4 expression was found on regulatory T (Treg) cells and central memory T (Tcm) cells, possibly explaining the reduced frequencies of these cells in peripheral blood during VL. The frequency of CCR6 expressing CD4+ T cells was also found to be lower in VL patients. Our results show that VL patients possess unique chemokine receptor expression patterns on the cell surface of CD4+ T cells, compared to EC. We also found increased levels of CCL3, CCL5 and CCL20 in VL plasma compared to EC. However, no changes were observed for CCL17 levels in VL plasma compared to EC, but their levels increased following treatment. We also observed reduced migration of VL CD4+ T cells, relative to other lymphocytes and mononuclear cells, irrespective of exogenous CCL5 presence. However, the frequency of CD4+ T cells migrating in response to CCL5 in EC individuals was similar. Additionally, we noted the frequency of CCR5+ Th1 cells was increased in VL patients compared to EC. However, no enhancement was seen in the migratory capacity of CCR5+ CD4+ T cells in the presence of recombinant CCL5. This suggests that the CCR5 receptor signalling pathway is less responsive towards exogenous CCL5, potentially due to high levels of CCL3 and CCL5 present in VL plasma, which may saturate surface CCR5. The upregulation of CCR5 expression and downregulation of CCR4 and CCR6 by CD4+ T cells distinguished VL patients from healthy individuals. These findings provide new insights into VL pathogenesis and could direct the development of new and improved disease diagnostics and therapeutics for treatment of VL.
Zoonotic visceral leishmaniasis is caused by Leishmania (Leishmania) infantum. Dogs are considered the most critical urban reservoirs of L. (L.) infantum due to their high infection rate and direct transmission to humans. The parasite has developed mechanisms to evade the host's defence system by inhibiting macrophage activation, thereby allowing it to replicate and survive. Pathogens such as viruses and bacteria can modify the host's epigenome, thereby facilitating their survival. Cellular reprogramming leads to epigenetic alterations that modulate chromatin, modify histones and DNA methylation, disrupt normal progression and compromise the continuity of cell differentiation. Histone deacetylases (HDACs) remove lysine acetyl groups from histones, resulting in chromatin alteration and gene silencing. Histone acetyltransferases regulate their function. In this study, we analysed the involvement of HDAC-1 in the defen mechanisms of DH82 macrophages infected with L. infantum. We observed that L. infantum infection increases HDAC1 levels and expression. Silencing HDAC1 with siRNA and the pharmacological inhibitor NaB decreased parasite load and increased iNOS expression, associated with increased histone acetylation at the iNOS promoter. The pharmacological inhibitor NaB also decreased IL-6, IL-10 and TNF-α levels in the culture supernatant of DH82 macrophages infected with L. infantum. Together, these findings indicate that L. infantum-induced HDAC1 upregulation modulates the expression of key innate immune response genes, contributing to the establishment of infection in canine macrophages.
The IL-33/ST2 pathway is important as part of the type 2 immune response against helminth infections. Mast cells express the highest levels of the IL-33 receptor subunit ST2 of any immune cell, and mast cells can mediate type 2 immune inflammation; however, the role of IL-33-driven mast cell responses in helminth infection is poorly understood. We sought to determine the role of mast cell ST2 expression during Heligmosomoides polygyrus bakeri (Hpb) infection by generating mast cell conditional ST2 knockout (MCPT5Cre × ST2f/f, cKO) mice. These mice have normal frequencies of mast cells at steady state but show specific and strong (albeit incomplete) knockdown of ST2 expression on mast cells. On Hpb infection, faecal egg and adult worm burden were similar between cKO and littermate controls, as were mast cell degranulation markers, serum IgE and goblet cell hyperplasia. Therefore, we conclude that mast cell ST2 does not play a dominant role in Hpb infection. To further investigate the immune response to infection in cKO and littermate controls, transcriptomic and proteomic changes were assessed in duodenal tissues in infected versus naïve mice in cKO and control mice. Minimal transcriptomic and proteomic changes were seen between genotypes, whereas substantial changes were seen between naïve and infected mice, regardless of genotype. Hpb infection induced local increases at the transcript and protein level for mast cell proteases (MCPT1 and MCPT2), resistin-like molecules (RELMα and RELMβ) and markers such as the phospholipase PLA2G4C and the pore-forming protein gasdermin C. Bulk proteomic analysis was also searched against the Hpb genome to identify Hpb proteins present in the duodenal tissues. A list of 60 Hpb proteins of interest was identified in infected duodenal samples, of which 18 contain a signal peptide and are present in the excretory/secretory products of Hpb (HES) (likely secretory products including immunomodulatory proteins); 28 proteins are present in HES but do not contain a signal peptide (likely excretory products); and 14 proteins are not present in HES (likely proteins present in the remnants of Hpb within the duodenum). This work thus provides datasets for changes in the mouse intestine due to Hpb infection, at both the transcript and protein level, as well as a dataset of Hpb proteins detectable in the mouse duodenum at day 14 of infection.
Tick saliva is known to cause immunosuppression and help pathogen transmission. Amblyomma sculptum is a public health concern as a vector of Rickettsia rickettsii. Another close-related species is Amblyomma cajennense sensu stricto (s.s.). The impact of saliva from these species on murine macrophages remains unclear. This study evaluated saliva from A. cajennense s.s. and A. sculptum in murine peritoneal macrophages, assessing cell viability, adhesion, morphology, reactive oxygen species (ROS) production, phagocytosis and cytokine secretion. Additionally, a proteomic analysis was conducted and the proteins that were secreted in salivas were estimated. Neither A. sculptum nor A. cajennense s.s. saliva did it affect viability, adhesion or morphology, but increased ROS production and phagocytic activity. A. sculptum saliva decreased IL-1β and increased TNF-α, whereas A. cajennense s.s. saliva increased IL-6 and IL-10. Proteomic analysis revealed 221 and 303 secreted proteins in A. cajennense s.s. and A. sculptum, respectively and the more abundant were vitellogenins, microplusins, serpins, cystatins, actin, beta actin and calponins. These findings suggest that saliva from each species modulates macrophage activity in distinct ways, eliciting pro- and anti-inflammatory responses. This is the first comparative evaluation of salivas from two species of the A. cajennense sensu lato complex, providing new insights into their interaction with innate immune cells.
Studies pertaining to Visceral leishmaniasis (VL) and its dermal sequel, Post Kala-azar Dermal Leishmaniasis (PKDL) are usually restricted to their immunopathogenesis, but the role, if any, regarding metabolic dysfunction of lymphocytes remains unanswered, and was the focus of this study. To delineate and correlate the functional and bioenergetic status of lymphocytes in patients with VL and PKDL. In Peripheral blood of patients with VL (n = 11) or PKDL (n = 18), along with healthy controls (n = 10), the T lymphocyte subsets (CD4+ and CD8+), their activation (CD69) and exhaustion (CD279) status were determined by flow cytometry. Oxidative phosphorylation (OXPHOS) and glycolysis were measured concomitantly in an extracellular flux analyser, whilst the status of mitochondrial respiration and glycolysis related genes was measured by qPCR. In comparison to healthy controls, the activation status remained unchanged in VL and PKDL cases but the frequency of exhausted T cells was significantly raised. These exhausted T cells showed an increased expression of OXPHOS in terms of signalling markers (SMAD3 and CPT1A) and oxygen consumption rate (OCR), along with an increased expression of mitochondrial respiration genes, which correlated positively with CD279+ T cells, whereas glycolysis remained unchanged. Patients with VL and PKDL demonstrated increased expression of CD279/Programmed cell death protein 1 (PD-1). This PD-1 signalling possibly activated SMAD3 and mitochondrial CPT1A, which led to increased mitochondrial respiration. This metabolic adaptation possibly facilitated sustenance of the exhausted T cell phenotype and contributed to disease progression. Targeting immunometabolism could well be a therapeutic approach worthy of future pharmacological consideration.
