Parasite Immunology最新文献

Fasciola hepatica is a trematode parasite of significant veterinary and public health importance, causing economic losses in livestock due to liver damage, weight loss and reduced milk production. Although triclabendazole (TCZ) is available for treatment, it does not prevent the disease or reinfection. Infected animals exhibit strong immunoregulation, increasing susceptibility to secondary infections and altering vaccine-induced antibody responses. This study investigates the humoral immune response in cattle infected with F. hepatica at different stages of infection and evaluates the effect of TCZ treatment on this response. It also examines how fasciolosis affects the antibody response induced by bacterial vaccines during early and chronic infection stages. Experimental infections in steers were conducted, with faecal and plasma samples collected at various intervals. The results showed a decrease in parasite-specific antibody avidity during infection. However, F. hepatica infection did not substantially modify antibody response to bacterial vaccines. This study underscores the need for further research on the impact of fasciolosis and its treatment on livestock vaccination efficacy.

For decades, parasitic worms such as Trichuris muris have been maintained in laboratory animals, providing insights into host-parasite interactions and host immune responses. The most used T. muris isolate is the E isolate, established in the laboratory in 1954. However, one concern with these model systems is the potential for laboratory-induced selection and therefore changes in host-parasite interactions. To address these concerns, we compare the E isolate with a recently isolated T. muris isolate (M isolate), established from wild house mice (Mus musculus domesticus, Isle of May, UK), in their capacity to infect laboratory mice. High dose infection of C57BL/6 mice revealed that significantly more parasites of the M isolate survived to the adult stage compared to the E isolate. Worm persistence was associated with heightened TNF-α and IL-10 secretion upon parasite-specific re-stimulation, and higher serum IgG1 and IgG2c levels, concomitant with an increase in T-bet⁺ and ICOS⁺ CD4⁺ T effector-memory cells. Differences in host response to the isolates were not as pronounced during low dose infection. Our study highlights the need for regular evaluation of lab-maintained parasite isolates against freshly isolated parasites to understand whether the established lab strains remain relevant model systems for our understanding of parasitic infections.

Toxoplasma gondii infection has been associated with psychoneurological disease in humans and behavioural changes in rodents. However, the mechanisms accounting for this have not been fully described and in some cases could be argued to reflect the severe neuropathology that some mice suffer during infection. Herein we employ a multi-omics approach to extensively examine BALB/c mice that are resistant to toxoplasmic encephalitis. Using a combination of LCMS (liquid chromatography-mass spectrometry) and RNAseq we demonstrate that infection alters the neurochemistry and the transcriptome of the brains of BALB/c mice. Notable changes to tryptophan, purine, arginine, nicotinamide and carnitine metabolism were observed in infected mice and this was accompanied with changes to the levels of a number of transcripts associated with enzymes these metabolic pathways. In addition, changes were seen in transcripts of many immunologically important genes known to contribute to immunity to T. gondii. Changes in the levels of additional transcripts during infection have previously been associated with psychoneurological diseases. The results demonstrate that the BALB/c mouse, with its relatively mild neurological disease, is a useful model for characterising the effects of T. gondii infection on murine neurochemistry. The results also implicate specific biochemical pathways in mediating these changes and should inform further mechanistic studies and suggest therapeutic targets.

Fasciolosis is a parasitosis of great importance for livestock, as well as for public health, as it is considered by the WHO as a neglected disease. Disease control is complex and reinfections make the use of therapeutic products an unsustainable method from an economic, environmental and health point of view. The aim of this study was to evaluate a new vaccine formulation for dairy cattle, containing soluble Fasciola hepatica antigens associated with Montanide 763 AVG and saponin adjuvants (FhSAMS). The vaccine was tested with two protocols, a single dose and a booster dose 6 months after the first dose. The FhSAMS vaccine proved to be safe, with no side effects. Furthermore, it was able to generate a more robust humoral immune response when a six-month booster dose was used, in addition to stimulating greater production of IFN-ʏ, indicating a Th1 profile immune stimulus.

Trypanosome parasites of the genus Trypanosoma cause African animal trypanosomosis, a devastating livestock disease plaguing sub-Saharan Africa. Unlike many protozoan parasites, these extracellular blood-borne pathogens directly engage the host's immune system. While the mouse model has provided valuable insights, a comprehensive understanding of the bovine immune response to trypanosomes remains elusive. Addressing the immune response in cattle, the most relevant host species, and how it takes part in mitigating the negative impact of the disease could contribute to setting up sustainable control strategies. This review summarises the current knowledge of the immune response in cattle during trypanosomosis. Following a brief overview of infection processes and bovine trypanotolerance, we present advances in the regulation of host innate, inflammatory and adaptive responses and delve into the key immunological players involved in immunoactivities and immunosuppression. We discuss how these mechanisms contribute to tolerance or susceptibility to infection, highlighting critical gaps in knowledge that require further investigation.

Schistosomiasis causes severe hepatic fibrosis, making it a global health issue. Moringa oleifera seed oil extract, which had antiparasitic, anti-inflammatory and antioxidant effects, was investigated as an alternative treatment. The 50 mice were divided into control, infected, praziquantel-treated, M. oleifera seed oil extract-treated and combined treatment groups. These treatments were examined for their effects on egg granulomas, hepatic enzymes, total protein, albumin, antioxidant enzymes and pro-inflammatory cytokines. M. oleifera seed oil and/or PZQ significantly reduced egg numbers, granuloma size and liver histopathology. M. oleifera seed oil reduced hepatic enzyme activity, increased total protein and albumin, and increased antioxidant enzyme activity while decreasing malondialdehyde. M. oleifera seed oil reduced the levels of pro-inflammatory cytokines. M. oleifera seed oil may treat schistosomiasis instead of PZQ due to its antifibrotic, immunomodulatory and schistosomicidal properties.

Leishmaniasis is considered one of the most critical health concerns in the world. Unfortunately, no protective vaccines exist and conventional treatments are relatively ineffective. Therefore, new strategies are necessary against leishmaniasis. In recent years, exosomes have shown promising therapeutic outcomes in various diseases, including infectious diseases. In this regard, we aimed to explore the effect of the exosome, pyrimethamine and their combination on the anti-parasitic function of RAW264.7 cells against Leishmania major. Exosomes were isolated from the C57BL/6 peritoneal macrophages. L. major infected and non-infected RAW264.7 cells treated with exosomes, pyrimethamine (PM), and exosomes along with PM. The effect of the treatments was analysed on phagocytosis, efferocytosis, the intracellular parasite count, arginase activity, nitric oxide (NO) and reactive oxygen species (ROS) production. Exosomes could significantly elevate the phagocytosis, efferocytosis, NO and ROS in both infected and non-infected groups (Pv < 0.05). The exosomes reduced the arginase activity in both groups (Pv < 0.05). The intracellular parasite count was significantly lower after treatment with exosomes (Pv < 0.05). These results demonstrate that MQ-derived exosomes can enhance in vitro anti-parasitic responses against L. major. This provides a potential pathway for more effective treatments and underscores the importance of further research in this area.

Leishmaniasis is a parasitic disease spread by the bite of an infected sandfly and caused by protozoan parasites of the genus Leishmania. Currently, there is no vaccine available for leishmaniasis in humans, and the existing chemotherapy methods face various clinical challenges. The majority of drugs are limited to a few toxic compounds, with some parasite strains developing resistance. Therefore, the discovery and development of a new anti-leishmanial compound is crucial. One promising strategy involves the use of nanoparticle delivery systems to accelerate the effectiveness of existing treatments. In this study, Amphotericin B (AmB) was incorporated into functionalized carbon nanotube (f-CNT) and evaluated for its efficacy against Leishmania major in vitro and in a BALB/c mice model. The increase in footpad thickness was measured, and real-time PCR was used to quantify the parasite load post-infection. Levels of nitric oxide and cytokines IL-4 and IFN-γ were also determined. We found that f-CNT-AmB significantly reduced the levels of promastigotes and amastigotes of the Leishmania parasite. The nanoparticle showed strong anti-leishmanial activity with an IC₅₀ of 0.00494 ± 0.00095 mg/mL for promastigotes and EC₅₀ of 0.00294 ± 0.00065 mg/mL for amastigotes at 72 h post-infection, without causing harm to mice macrophages. Treatment of infected BALB/c mice with f-CNT-AmB resulted in a significant decrease in cutaneous leishmania (CL) lesion size in the foot pad, as well as reduced Leishmania burden in both lymph nodes and spleen. The levels of nitric oxide and IFN-γ significantly increased in the f-CNT-AmB treated groups. Also, our results showed that the level of IL-4 significantly decreased after f-CNT-AmB treatment in comparison to other groups. In conclusion, our results demonstrate that AmB loaded into f-CNT is significantly more effective than AmB alone in inhibiting parasite propagation and promoting a shift towards a Th1 response.

Interleukin 27 (IL-27) is a cytokine that regulates susceptibility to Leishmania infantum infection in humans and experimental models. This cytokine has not yet been described in canine leishmaniasis (CanL). Therefore, we investigated whether IL-27 has a regulatory role in CanL. The EBI3 and p28 subunits of IL-27 were measured in splenic leukocytes culture supernatant from dogs with CanL and compared to control dogs. We also correlated EBI3 and p28 levels with IL-21, anti-L. infantum antibodies and parasite loads. We performed functional assays followed by IL-27 blockade and measured parasite loads, production of cytokines in splenic leukocytes culture supernatant, and the expression of PD-1, CTLA-4, phospho-Stat-1/3, T-bet, GATA3 and nitric oxide production (NO). Both IL-27 subunits increased in the supernatant of dogs with CanL compared to control dogs. EBI3 and p28 levels showed a moderate positive correlation with IL-21 (r = 0.67, p < 0.0001 and r = 0.45, p < 0.012, respectively), and the EBI3 subunit was positively associated with anti-L. infantum IgG antibodies (r = 0.38, p < 0.040) and parasite load (r = 0.47, p < 0.009). IL-27 and IL-21 participate of immune responses in CanL. IL-27 may be associated with the failure of immunity to control parasite replication via upregulation of the expression of PD-1, CTLA-4, T-bet and NO in splenic leukocytes from dogs with CanL. These findings suggest that the pathways regulated by IL-27 are involved in CanL pathogenesis in the host, and may be targets for new therapies.