Parasite Immunology最新文献

Haemonchus contortus poses a major threat to small ruminant production in subtropical regions worldwide. Unfortunately, there is growing anthelmintic resistance, and the only licensed vaccine has limitations. This paper aimsto review the use of RNA-sequencing in understanding the immune responses of small ruminants to H. contortus infection, focusing on identifying differentially expressed genes and elucidating key immune pathways associated with resistance and susceptibility. This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement guidelines and Population, Intervention, Control, and Outcome framework covering publications from January 2015 to December 2023. RNA-seq identified the activation of key immune pathways, such as Th1/Th2, NK cell, B cell receptor signalling, MAPK, CAMs, and TNF signalling. There was upregulation of a range of PRRs, including TLRs and CLECs, in the resistant sheep, suggesting a crucial role for trained innate immune cells in resistance. However, there are no direct comparisons of TLR and CLEC expression between resistant and susceptible goats. This shows that there is a gap in understanding of the immune response mechanisms in goats. Addressing these knowledge gaps will lead to the development of more effective and sustainable control strategies.

Schistosomiasis japonica is a parasitic disease that seriously endangers human health. Patients with advanced Schistosoma japonicum infection often suffer from cirrhosis and portal hypertension. Splenectomy has been widely used in the treatment of these patients. Previous studies have confirmed that S. japonicum infection is closely related to the gut microbiota, but the impact of splenectomy on the gut microbiota of patients with advanced S. japonicum infection remains unclear. This study used 16sRNA sequencing technology to compare the differences in intestinal flora between patients with advanced S. japonicum infection who underwent splenectomy and non-surgical patients. We focused on the changes in the species composition, diversity and functions of the intestinal flora. Our study shows that dysbiosis of the gut microbiome occurred in patients with advanced S. japonicum infection, including changes in abundance and diversity and the disorder of biological function. The intestinal flora structure, diversity and function of patients who underwent splenectomy were significantly changed compared with those who did not undergo surgery.

The disease named tropical theileriosis is caused by the protozoan pathogen Theileria annulata (T. annulata) transmitted through Hyalomma species ticks. The current study has been designed to determine the haematological, inflammatory and oxidative stress status in cattle naturally infected with T. annulata. The study consisted of two groups: a control group (10 cattle) and a theileriosis group (10 cattle). Compared to the control group, the animals in the theileriosis group exhibited a significant decrease in erythrocyte count, haemoglobin count, haematocrit levels and mean corpuscular haemoglobin concentration, while a notable increase in mean corpuscular volume was observed (p < 0.001; p < 0.01; p < 0.01; p < 0.05; p < 0.05, respectively). However, no significant differences were found between the groups for the other haematological indices (p > 0.05). In terms of oxidative stress markers, the theileriosis group exhibited higher malondialdehyde (MDA) (p < 0.001) and significantly lower superoxide dismutase (SOD) (p < 0.001) levels compared to the control group. No significant difference was observed between the groups in terms of catalase (CAT) levels. Compared to the control group, haptoglobin (Hp) (p < 0.001) and procalcitonin (PCT) (p < 0.001) levels were significantly higher in the theileriosis group, while no significant difference was observed in neopterin levels between the two groups (p > 0.05). In conclusion, significant differences were identified in haematological indices, acute phase response, inflammatory marker levels, and oxidative stress marker levels in theileriosis. Additionally, Hp and PCT levels may be crucial in determining the inflammatory status.

Canine visceral leishmaniasis (CVL) is a zoonotic disease of great worldwide importance and can be prevented by vaccinating seronegative dogs. The objective of the present systematic review and meta-analysis is to verify the efficacy rate of vaccines tested in dogs against CVL or L. infantum infection. We used PRISMA guidelines for this review and Pubmed, Web of Science, Scopus, Cochrane, Scielo and CABI to find studies about vaccines against CVL in dogs. Articles were analysed and grouped according to the antigens used. The risk of bias analysis was performed using SYRCLE's RoB tool and meta-analysis using R Statistical language. The final analysis was conducted using 22 studies that assessed DNA, excreted/secreted proteins and subunit vaccines, involving a total of 92 animals, 96 animals and 78 animals, respectively. Regarding DNA vaccines, the analyses revealed non-significant results in terms of preventing parasite presence in the organs or the onset of clinical signs. However, subunit vaccines demonstrated statistically significant results concerning parasite presence in the organs, but not when it comes to clinical signs. Additionally, there was no statistically significant difference observed in parasite burden in the organs or clinical signs for the excreted/secreted vaccines. The meta-analysis indicated that subunit and excreted/secreted protein vaccines were significantly more effective in preventing parasites in vaccinated animals compared to both DNA-based vaccines and control groups. Heterogeneity among studies is a limitation, emphasising the need for standardised protocols for reliable comparisons.

Toxoplasma gondii, an obligate, intracellular, protozoan parasite, is known to infect a wide range of warm-blooded animals, including livestock, marine mammals and humans leading to the development of toxoplasmosis. The dense granule antigens (GRAs) have garnered crucial role in parasite survival, virulence and the formation of the parasitophorous vacuole. The study focusing on the GRA10 protein of T. gondii aims to elucidate its features further to support its potential inclusion in future vaccine formulations. The present study provided an exhaustive elucidation of the key characteristics of the GRA10 protein, encompassing its presence of a transmembrane domain, physico-chemical properties, subcellular localization, potential epitopes recognised by B-cells and T-cells, secondary and tertiary structures, as well as other significant attributes of this protein. The results indicated that the GRA10 protein possesses a total of 192 possible post-translational modification sites, with no transmembrane domains being detected within its structure. In terms of secondary structure, the GRA10 protein is composed of 27.74% alpha-helix, 13.53% extended strand and 58.72% random coil elements. Additionally, various potential B- and T-cell epitopes were pinpointed for the GRA10 protein, suggesting its immunogenic properties. The assessment of antigenicity and allergenicity further confirmed that GRA10 is immunogenic but non-allergenic, making it a promising candidate for further study. Furthermore, the induction of IFN-γ and IL-4 highlighted the ability of related MHC-II molecules to interact with GRA10, indicating its potential role in immune responses. These findings shed light on the multifaceted nature of the GRA10 protein and its significance in immunological processes. The study presented crucial fundamental and theoretical information regarding GRA10 in order to facilitate the creation of a potent vaccine against both acute and chronic toxoplasmosis, warranting additional in vivo examinations.

Evidence from multiple data sources indicates that toxocariasis might play a role in the allergic asthma in children. This case-control study investigated the connection between Toxocara seropositivity and allergic asthma. It also sought to identify the conventional risk factors associated with both asthma and Toxocara infection. In this case-control study, 200 allergic asthma children and 208 children with no history of allergic asthma were included as the healthy group. Sera samples were examined for specific anti-Toxocara IgG antibodies using a serological assay. The overall prevalence of toxocariasis was 6.9% among children. The seroprevalence of toxocariasis in asthmatic children and healthy children was 8% and 5.8%, respectively, with no significant difference (p-value = 0.373). In subgroup analyses based on sociodemographic, Toxocara infection seropositivity was significantly associated with two independent variables, including the father's occupation (p-value = 0.017) and soil contact in asthmatic children (p-value = 0.033). Our results showed a higher prevalence of Toxocara infection in asthmatic children compared to healthy controls, but this difference was not statistically significant. To gain a clearer understanding and comparison of Toxocara infection rates between asthmatic and healthy children, additional comprehensive studies with larger sample sizes and diverse detection methods using different antigenic sources are required.

Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania. The treatment of intracellular infections such as leishmaniasis is often challenging due to limited drug access to infected cells and the development of drug resistance. Therefore, the development of new antileishmanial compounds is essential. Paromomycin sulphate (PM) has shown promise as an antileishmanial drug, and one way to enhance its effectiveness is through appropriate delivery systems. Solid lipid nanoparticles (SLN) are being explored as a potential delivery system for PM, as they offer advantages over other colloidal carriers. In a recent study, PM was loaded into solid lipid nanoparticles (PM-SLN) and its oral effectiveness was evaluated in treating Leishmania (L.) major-infected mice. The study measured footpad swelling, quantified parasite load through real-time PCR and assessed levels of cytokines such as interleukin-4 (IL-4) and gamma interferon (IFN-c), nitric oxide (NO) and Arginase (ARG). Overall, the study demonstrated that oral administration of the PM-SLN formulation is safe and effective in treating leishmaniasis. The SLN in the PM-SLN compound improved the killing of parasites by PM and stimulated a Th1 immune response, indicating its potential as a treatment for leishmaniasis.

Tritrichomonas foetus is a protozoan parasite that causes bovine trichomonosis (also referred to as trichomoniasis) resulting in substantial economic loss in extensive grazing systems. The parasite colonises the reproductive tracts of both male and female cattle, being asymptomatic in males but causing early reproductive failure in infected females. This systematic review aimed to examine research manuscripts describing the development of T. foetus vaccines, the strategies employed, and the immune response associated with T. foetus infection. A systematic review was conducted using indexed sources on Scopus, PubMed, Web of Science, and Embase to search for published vaccine development studies in English utilising either experimental or commercial T. foetus vaccines for bovine trichomonosis. Search terms (cattle, bull, heifer, vaccine, immune response, and Tritrichomonas foetus) were entered into the indexed sources and with no limit was set for the year of publication. Among 374 studies imported for screening, 96 were duplicates, and 255 were excluded for irrelevancy as these studies did not meet the inclusion criteria (report original data, vaccine tests in cattle, and used either commercial or experimental vaccines that incorporated antigens from T. foetus). A further five studies were excluded after full-text review as either the publication described a different target pathogen or the full text was not in English. Eighteen studies met the inclusion criteria and were subjected to data extraction using the Covidence platform. Studies included in the systematic review reported three vaccine strategies, including subunit, cell fraction, and whole-cell killed vaccines. This review considers the design, rationale, and results of each of the 18 studies to provide a comprehensive overview of the current knowledge and to inform future research agendas. While whole-cell killed vaccines are most prevalent, they have shown superior efficacy compared to subunit vaccines studied to date. One study using a purified fractions of T. foetus cell membranes as vaccine demonstrated higher efficacy and higher calving rates compared to the whole-cell killed vaccine. All of these methods require cell culture growth of T. foetus which can be challenging compared to the production of recombinant proteins. At this stage, no T. foetus recombinant antigens have been reported. Advances in understanding the parasite's genome, pathogenesis, host-parasite interactions, and host immune responses to T. foetus will provide opportunities for the development of novel vaccine strategies for bovine trichomonosis.

Leishmania (Viannia) braziliensis causes cutaneous and mucocutaneous leishmaniasis. Macrophages are host cells for parasite replication and act as effector cells against the parasite. The two main macrophage phenotypes (M1 and M2) and their polarisation states have been implicated in Leishmania infection despite scarce data on L. (V.) braziliensis. In this study, we investigated the temporal and spatial distribution and predominance of M1 and M2 macrophages during L. (V.) braziliensis infection in Balb/c mice. Animals were infected with L. (V.) braziliensis promastigotes and were monitored for 25 weeks. Histopathological evaluation of footpad lesions, regional lymph nodes, and spleen; cellularity; and macrophage population quantification of M1, and M2 macrophages by flow cytometry were performed in different tissues. The results showed that after infection with either strain of L. (V.) braziliensis the lesions were small and non-ulcerated. The dissemination of parasites to tissues reinforced the characteristic visualisation of dermotropicL. (V.) braziliensis. The proportion of M2 macrophages in different tissues was significantly higher than that of M1 macrophages. Overall, the results reported here confirm that Leishmania an intracellular parasite, promotes and influences macrophage phenotype polarisation in different tissues over time, and researchers testing therapies based on macrophage phenotype regulation should consider this evidence.

Gastrointestinal helminths interact with the gut microbiota in ways that shape microbiota structure and function, but these effects are highly inconsistent across studies. One factor that may help explain variation in parasite-microbiota interactions is host sex since helminths can induce sex-specific changes in feeding behaviour and diet that might cascade to shape gut microbial communities. We tested this idea using an anthelmintic treatment experiment in wild Grant's gazelles (Nanger granti). We found that in males, anthelmintic treatment induced short-term shifts in microbial diversity and structure within ~40-70 days, but in females, treatment had effects on microbiota structure that emerged over a longer period of ~500 days. Long-term effects of treatment on the microbiota of females were potentially due to sex-specific changes in feeding behaviour since deworming nearly doubled the time females spent feeding, but did not affect feeding time in males. In support of this idea, anthelmintic treatment eliminated associations between microbial diversity and diet in females, and treated females maintained a more stable abundance of microbial taxa and predicted functions. Together, these findings suggest that accounting for host traits can help uncover mechanisms, such as changes in diet, by which helminths interact with the microbiota.