Four Chemotherapeutic Compounds That Limit Blood-Brain-Barrier Invasion by Toxoplasma gondii.

BACKGROUND: Toxoplasma gondii, an intracellular protozoan parasite, exists in the host brain as cysts, which can result in Toxoplasmic Encephalitis (TE) and neurological diseases. However, few studies have been conducted on TE, particularly on how to prevent it. Previous proteomics studies have showed that the expression of C3 in rat brains was up-regulated after T. gondii infection. METHODS: In this study, we used T. gondii to infect mice and bEnd 3 cells to confirm the relation between T. gondii and the expression of C3. BEnd3 cells membrane proteins which directly interacted with C3a were screened by pull down. Finally, animal behavior experiments were conducted to compare the differences in the inhibitory ability of TE by four chemotherapeutic compounds (SB290157, CVF, NSC23766, and Anxa1). RESULTS: All chemotherapeutic compounds in this study can inhibit TE and cognitive behavior in the host. However, Anxa 1 is the most suitable material to inhibit mice TE. CONCLUSION: T. gondii infection promotes TE by promoting host C3 production. Anxa1 was selected as the most appropriate material to prevent TE among four chemotherapeutic compounds closely related to C3.

A Double-Edged Sword: Complement Component 3 in Toxoplasma gondii Infection.

Sprague Dawley rats and Kunming (KM) mice are artificially infected with type II Toxoplasma gondii strain Prugniaud (Pru) to generate toxoplasmosis, which is a fatal disease mediated by T. gondii invasion of the central nervous system (CNS) by unknown mechanisms. The aim is to explore the mechanism of differential susceptibility of mice and rats to T. gondii infection. Therefore, a strategy of isobaric tags for relative and absolute quantitation (iTRAQ) is established to identify differentially expressed proteins (DEPs) in the rats' and the mice's brains compared to the healthy groups. In KM mice, which is susceptible to T. gondii infection, complement component 3 (C3) is upregulated and the tight junction (TJ) pathway shows a disorder. It is presumed that T. gondii-stimulated C3 disrupts the TJ of the blood-brain barrier in the CNS. This effect allows more T. gondii passing to the brain through the intercellular space.

Immuno-efficacy of DNA vaccines encoding PLP1 and ROP18 against experimental Toxoplasma gondii infection in mice.

We constructed a new plasmid pIRESneo/ROP18/PLP1 that was injected intramuscularly into Kunming mice to evaluate its immune efficacy. The immunized mice exhibited significantly increased serum IgG2a levels, lymphocyte counts and Th1-type cytokine (IL-2, IL-12 and IFN-γ) levels. Moreover, the immunized mice exhibited longer survival times (44.7 ± 2.1 days for ROP18/PLP1 and 47.2 ± 2.9 days for ROP18/PLP1 + IL-18) and lower brain cyst burden (68.9% for ROP18/PLP1 and 72.4% for ROP18/PLP1 + IL-18) than control mice after T. gondii challenge. Our results demonstrate that the multiple-gene DNA vaccine including both ROP18 and PLP1 elicits greater protection against T. gondii challenge and stronger immunogenicity than single-gene vaccines.

Protective efficacy of recombinant canine adenovirus type-2 expressing TgROP18 (CAV-2-ROP18) against acute and chronic Toxoplasma gondii infection in mice.

BACKGROUND: The use of recombinant viral vectors expressing T. gondii antigens is a safe and efficient approach to induce immune responses against the parasite, as well as a valuable tool for vaccine development. We have previously prolonged the survival time of mice challenged with the RH strain of T. gondii by immunizing the mice with a eukaryotic vector expressing the protein ROP18 of T. gondii. We are now looking for ways to improve this vaccination strategy and enhance protection. METHODS: In this study, we constructed and characterized a novel recombinant canine adenovirus type 2 expressing ROP18 (CAV-2-ROP18) of T. gondii by cytopathic effect (CPE) and indirect immunofluorescence assay (IFA) following transfection into MDCK cells. Intramuscular immunization of Kunming mice with CAV-2-ROP18 was carried out to evaluate humoral and cellular immune responses. RESULTS: The vaccination of experimental mice with CAV-2-ROP18 elicited antibody production against ROP18, including high levels of a mixed IgG1/IgG2a and significant production of IFN-γ or IL-2, and displayed a significant bias towards a helper T cell type 1 (Th1) profile. Furthermore, the presence of T. gondii-specific IFN-γ-production and TNF-α-production T cells was elicited in both CD4+ and CD8+ T cell compartments. Significantly higher survival rates (40%) occurred in the experimental group, and a reduction in brain cyst burden was detected in vaccinated mice. CONCLUSION: These results demonstrate the potential use of a CAV vector harboring the ROP18 gene in the development of a vaccine against acute and chronic toxoplasmosis.

Biological characteristics of Chinese precocious strain of eimeria acervulina and its immune efficacy against different field strains.

In this study, the biologic characteristics of one experimental precocious strain of Eimeria acervulina and seven field isolates from different geographic locations in China were compared, and the immune efficacy of two precocious strains against coccidiosis in chickens was assessed to explore their potential use as coccidiosis vaccines. All the different strains were purified by single oocyst separation and their monospecificity was confirmed using E acervulina-specific PCR assays. The average sizes of E. acervulina oocysts were 18.28-20.19 X 14.09-14.79 microm and the shape indexes were from 1.28 to 1.40. The prepatent periods ranged from 93 to 115 hr, except for the Heyuan precocious strain (HYP; 75 hr). Chickens infected with Huadu field strain (GHD) produced the highest oocyst output whereas HYP induced the lowest level. When inoculated with 50,000 sporulated oocysts or more, the average weight gains of infected chickens were reduced, with apparent clinical symptoms. To assess the immunogenicity of precocious strains HYP and Baoding (BDP), birds were orally immunized and challenged with seven different field strains of E. acervulina. Body weight gain, fecal oocyst output, and gut lesion scores were compared to evaluate their vaccine potential. The results showed that the average body weight gains of chickens in all the vaccinated and challenged groups were higher than those of nonvaccinated and challenged groups. In general, oocyst shedding was reduced 34.39%-95.31% and gut lesion scores decreased 31.03%-86.21% compared with unvaccinated and challenged control chickens. In summary, this study indicated that the precocious strains of E. acervulina could induce a protective immune effect with various responses against coccidiosis caused by different field strains.

Unlocking the role of EIF5A: A potential diagnostic marker regulating the cell cycle and showing negative correlation with immune infiltration in lung adenocarcinoma.

BACKGROUND: Despite EIF5A upregulation related to tumor progression in LUAD (lung adenocarcinoma), the underlying mechanisms remain elusive. In addition, there are few comprehensive analyses of EIF5A in LUAD. METHODS: We investigated the EIF5A expression level in LUAD patients using data from the TCGA and GEO databases. We employed qRT-PCR and western blot to verify EIF5A expression in cell lines, while immunohistochemistry was utilized for clinical sample analysis. We analyzed EIF5A expression in tumor-infiltrating immune cells using the TISCH database and assessed its association with immune infiltration in LUAD using the "ESTIMATE" R package. Bioinformatics approaches were developed to discover the EIF5A-related genes and explore EIF5A potential mechanisms in LUAD. Proliferation ability was verified through CCK-8, clone formation, and EdU assays, while flow cytometry assessed apoptosis and cell cycle. Western blot was used to detect the expression of pathway-related proteins. RESULTS: EIF5A was significantly upregulated in LUAD. Moreover, we constructed a MAZ-hsa-miR-424-3p-EIF5A transcriptional network. We explored the potential mechanism of EIF5A in LUAD and further investigated the cAMP signaling pathway and the cell cycle. Finally, we proved that EIF5A silencing induced G1/S Cell Cycle arrest, promoted apoptosis, and inhibited proliferation via the cAMP/PKA/CREB signaling pathway. CONCLUSION: EIF5A serves as a prognostic biomarker with a negative correlation to immune infiltrates in LUAD. It regulated the cell cycle in LUAD by inhibiting the cAMP/PKA/CREB signaling pathway.

Differential transcriptome study on the damage of testicular tissues caused by chronic infection of T. gondii in mice.

BACKGROUND: Toxoplasma gondii is an intracellular protozoan parasite that is widely distributed in humans and warm-blooded animals. T. gondii chronic infections can cause toxoplasmic encephalopathy, adverse pregnancy, and male reproductive disorders. In male reproduction, the main function of the testis is to provide a stable place for spermatogenesis and immunological protection. The disorders affecting testis tissue encompass abnormalities in the germ cell cycle, spermatogenic retardation, or complete cessation of sperm development. However, the mechanisms of interaction between T. gondii and the reproductive system is unclear. The aims were to study the expression levels of genes related to spermatogenesis, following T. gondii infection, in mouse testicular tissue. METHODS: RNA-seq sequencing was carried out on mouse testicular tissues from mice infected or uninfected with the T. gondii type II Prugniaud (PRU) strain and validated in combination with real-time quantitative PCR and immunofluorescence assays. RESULTS: The results showed that there were 250 significant differentially expressed genes (DEGs) (P < 0.05, |log2fold change| â‰§ 1). Bioinformatics analysis showed that 101 DEGs were annotated to the 1696 gene ontology (GO) term. While there was a higher number of DEGs in the biological process classification as a whole, the GO enrichment revealed a significant presence of DEGs in the cellular component classification. The Arhgap18 and Syne1 genes undergo regulatory changes following T. gondii infection, and both were involved in shaping the cytoskeleton of the blood-testis barrier (BTB). The number of DEGs enriched in the MAPK signaling pathway, the ERK1/2 signaling pathway, and the JNK signaling pathway were significant. The PTGDS gene is located in the Arachidonic acid metabolism pathway, which plays an important role in the formation and maintenance of BTB in the testis. The expression of PTGDS is downregulated subsequent to T. gondii infection, potentially exerting deleterious effects on the integrity of the BTB and the spermatogenic microenvironment within the testes. CONCLUSIONS: Overall, our research provides in-depth insights into how chronic T. gondii infection might affect testicular tissue and potentially impact male fertility. These findings offer a new perspective on the impact of T. gondii infection on the male reproductive system.

The opposing effect of acute and chronic Toxoplasma gondii infection on tumor development.

BACKGROUND: The interplay between Toxoplasma gondii infection and tumor development is intriguing and not yet fully understood. Some studies showed that T. gondii reversed tumor immune suppression, while some reported the opposite, stating that T. gondii infection promoted tumor growth. METHODS: We created three mouse models to investigate the interplay between T. gondii and tumor. Model I aimed to study the effect of tumor growth on T. gondii infection by measuring cyst number and size. Models II and III were used to investigate the effect of different stages of T. gondii infection on tumor development via flow cytometry and bioluminescent imaging. Mouse strains (Kunming, BALB/c, and C57BL/6J) with varying susceptibilities to tumors were used in the study. RESULTS: The size and number of brain cysts in the tumor-infected group were significantly higher, indicating that tumor presence promotes T. gondii growth in the brain. Acute T. gondii infection, before or after tumor cell introduction, decreased tumor growth manifested by reduced bioluminescent signal and tumor size and weight. In the tumor microenvironment, CD4+ and CD8+ T cell number, including their subpopulations (cytotoxic CD8+ T cells and Th1 cells) had a time-dependent increase in the group with acute T. gondii infection compared with the group without infection. However, in the peripheral blood, the increase of T cells, including cytotoxic CD8+ T cells and Th1 cells, persisted 25 days after Lewis lung carcinoma (LLC) cell injection in the group with acute T. gondii. Chronic T. gondii infection enhanced tumor growth as reflected by increase in tumor size and weight. The LLC group with chronic T. gondii infection exhibited decreased percentages of cytotoxic CD8+ T cells and Th1 cells 25 days post-LLC injection as compared with the LLC group without T. gondii infection. At week 4 post-LLC injection, chronic T. gondii infection increased tumor formation rate [odds ratio (OR) 1.71] in both KM and BALB/c mice. CONCLUSIONS: Our research elucidates the dynamics between T. gondii infection and tumorigenesis. Tumor-induced immune suppression promoted T. gondii replication in the brain. Acute and chronic T. gondii infection had opposing effects on tumor development.

Deciphering the epidemiological dynamics: Toxoplasma gondii seroprevalence in mainland China's food animals, 2010-2023.

Background: Toxoplasma gondii (T. gondii) is a significant protozoan pathogen among food animals. Despite the threat to public health by T. gondii infections, there's limited understanding of its seroprevalence and trends in food animals across mainland China. This study aimed to estimate the seroprevalence of T. gondii infections among swine, sheep, goats, chickens, and cattle in mainland China from 2010 to 2023. Methods: We searched cross-sectional studies published between 2010 and 2023 that reported the prevalence of T. gondii in food animals from databases including PubMed, Embase, Web of Science, China Biology Medicine Disc (CBM), China National Knowledge Infrastructure (CNKI), Wanfang data, and the China Science and Technology Journal Database (CQVIP). We performed subgroup analyses to explore the impact of different factors on the seroprevalence of T. gondii. Pooled estimates of T. gondii seroprevalence were calculated with a random-effects model. Results: An analysis of 184 studies involving 211985 animals revealed a T. gondii overall seroprevalence of 15.3% (95% CI: 13.1-17.8). Although the seroprevalence of food animals across mainland China was relatively stable from 2010 to 2023, notable variations were observed across different animal types and regions (P < 0.01), along with changes in geographical distribution. Sample type, detection method, animal age, and history of abortion were identified as key risk factors for T. gondii seroprevalence. Conclusion: The study conducted a meta-analysis on the seroprevalence of T. gondii in mainland China's Food Animals from 2010 to 2023, and identified key risk factors. These findings advance our understanding of T. gondii infection dynamics, offering critical insights for developing control strategies and guiding public health policies.

Insight into the current Toxoplasma gondii DNA vaccine: a review article.

INTRODUCTION: Toxoplasma gondii (T.gondii) is a widespread protozoan with significant economic losses and public health importance. But so far, the protective effect of reported DNA-based vaccines fluctuates widely, and no study has demonstrated complete protection. AREAS COVERED: This review provides an inclusive summary of T. gondii DNA vaccine antigens, adjuvants, and some other parameters. A total of 140 articles from 2000 to 2021 were collected from five databases. By contrasting the outcomes of acute and chronic challenges, we aimed to investigate and identify viable immunological strategies for optimum protection. Furthermore, we evaluated and discussed the impact of several parameters on challenge outcomes in the hopes of developing some recommendations to assist better future horizontal comparisons among research. EXPERT OPINION: In the coming five years of research, the exploration of vaccine cocktails combining invasion antigens and metabolic antigens with genetic adjuvants or novel DNA delivery methods may offer us desirable protection against this multiple stage of life parasite. In addition to finding a better immune strategy, developing better in silico prediction methods, solving problems posed by variables in practical applications, and gaining a more profound knowledge of T.gondii-host molecular interaction is also crucial towards a successful vaccine.

Multiomics and bioinformatics identify differentially expressed effectors in the brain of Toxoplasma gondii infected masked palm civet.

Introduction: The masked palm civet (Paguma larvata) serves as a reservoir in transmitting pathogens, such as Toxoplasma gondii, to humans. However, the pathogenesis of T. gondii infection in masked palm civets has not been explored. We studied the molecular changes in the brain tissue of masked palm civets chronically infected with T. gondii ME49. Methods: The differentially expressed proteins in the brain tissue were investigated using iTRAQ and bioinformatics. Results: A total of 268 differential proteins were identified, of which 111 were upregulated and 157 were downregulated. KEGG analysis identified pathways including PI3K-Akt signaling pathway, proteoglycans in cancer, carbon metabolism, T-cell receptor signaling pathway. Combing transcriptomic and proteomics data, we identified 24 genes that were differentially expressed on both mRNA and protein levels. The top four upregulated proteins were REEP3, REEP4, TEP1, and EEPD1, which was confirmed by western blot and immunohistochemistry. KEGG analysis of these 24 genes identified signaling cascades that were associated with small cell lung cancer, breast cancer, Toll-like receptor signaling pathway, Wnt signaling pathways among others. To understand the mechanism of the observed alteration, we conducted immune infiltration analysis using TIMER databases which identified immune cells that are associated with the upregulation of these proteins. Protein network analysis identified 44 proteins that were in close relation to all four proteins. These proteins were significantly enriched in immunoregulation and cancer pathways including PI3K-Akt signaling pathway, Notch signaling pathway, chemokine signaling pathway, cell cycle, breast cancer, and prostate cancer. Bioinformatics utilizing two cancer databases (TCGA and GEPIA) revealed that the four genes were upregulated in many cancer types including glioblastoma (GBM). In addition, higher expression of REEP3 and EEPD1 was associated with better prognosis, while higher expression of REEP4 and TEP1 was associated with poor prognosis in GBM patients. Discussion: We identified the differentially expressed genes in the brain of T. gondii infected masked palm civets. These genes were associated with various cellular signaling pathways including those that are immune- and cancer-related.

Pseudorabies gD protein protects mice and piglets against lethal doses of pseudorabies virus.

Introduction: Pseudorabies (PR) is a highly contagious viral disease caused by the pseudorabies virus (PRV), which can cause disease in a wide range of domestic and wild animals. Studies have shown that new mutant strains have emerged in pig farms in many regions and that commercial inactivated and live attenuated vaccines are becoming less effective at protecting pigs. Methods: Porcine pseudorabies glycoprotein D (gD) gene (GenBank: QEY95774.1) with hexa-His tag to the C terminus for further purification processes was cloned into the lentiviral expression plasmid pLV-CMV-eGFP by restriction enzyme, the resulting plasmid was designated as pLV-CMV-gD. HEK-293T cells with robust and stable expression of recombinant gD protein was established by infection with recombinant lentivirus vector pLV-CMV-gD. We expressed porcine pseudorabies virus gD protein using HEK-293T cells. Results: We describe in this study that individual gD proteins produced by a mammalian cell expression system are well immunogenic and stimulate high levels of PRV-specific and neutralizing antibodies in mice and piglets. All mice and piglets survived lethal doses of PRV, significantly reducing the amount of PRV virus in piglets' lymph nodes, lungs, spleen, and other tissues. It also significantly reduced the time cycle and amount of viral excretion from piglets to the environment through the nasal and anal cavities. Discussion: The results suggest that PRV gD protein is expected to be a potential candidate for the preparation of genetically engineered PR vaccines for the prevention of PRV infection and the control of PR epidemics.

Contracaecum rudolphii B: gene content, arrangement and composition of its complete mitochondrial genome compared with Anisakis simplex s.l.

In the present study, we sequenced the complete mt genome (14,022 bp) of parasitic nematode Contracaecum rudolphii B and its structure and organization compared with Anisakis simplex s.l. The mt genome of C. rudolphii B is slightly longer than that of A. simplex s.l. (13,916 bp). C. rudolphii B mt genome is circular, and consists of 36 genes, including 12 genes for proteins, 2 genes for rRNA and 22 genes for tRNA. This genome contains a high A+T (70.5%) content. The mt gene order for C. rudolphii B is the same as those for A. simplex s.l., but it is distinctly different from other nematodes compared. The start codons inferred in the mt genome of C. rudolphii B are TTG and ATT. Six protein-coding genes use TAA as a stop codon whereas five genes use T and one genes use TAG as a termination codon. This pattern of codon usage reflects the strong bias for A and T in the mt genome of C. rudolphii B. Phylogenetic analyses using concatenated amino acid sequences of the 12 protein-coding genes, with three different computational algorithms (Bayes, ML and MP), all revealed distinct groups with high statistical support, indicating that C. rudolphii B and A. simplex s.l. is distinct but closely related species. These data provide additional novel mtDNA markers for studying the molecular epidemiology and population genetics of the C. rudolphii B, and should have implications for the molecular diagnosis, prevention and control of anisakidosis in humans and animals.

Unveiling of brain transcriptome of masked palm civet (Paguma larvata) with chronic infection of Toxoplasma gondii.

BACKGROUND: The aim of this study was to gain an understanding of the transcriptomic changes that occur in a wild species when infected with Toxoplasma gondii. The masked palm civet, an artifically domesticated animal, was used as the model of a wild species. Transcriptome analysis was used to study alterations in gene expression in the domesticated masked palm civet after chronic infection with T. gondii. METHODS: Masked palm civets were infected with 105 T. gondii cysts and their brain tissue collected after 4 months of infection. RNA sequencing (RNA-Seq) was used to gain insight into the spectrum of genes that were differentially expressed due to infection. Quantitative reverse-transcription PCR (qRT-PCR) was also used to validate the level of expression of a set of differentially expressed genes (DEGs) obtained by sequencing. RESULTS: DEGs were screened from the sequencing results and analyzed. A total of 2808 DEGs were detected, of which 860 were upregulated and 1948 were downregulated. RNA-Seq results were confirmed by qRT-PCR. DEGs were mainly enriched in cellular process and metabolic process based on gene ontology enrichment analysis. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that transcriptional changes in the brain of infected masked palm civets evolved over the course of infection and that DEGs were mainly enriched in the signal transduction, immune system processes, transport and catabolic pathways. Finally, 10 essential driving genes were identified from the immune signaling pathway. CONCLUSIONS: This study revealed novel host genes which may provide target genes for the development of new therapeutics and detection methods for T. gondii infection in wild animals.

SARS-CoV-2: An Updated Review Highlighting Its Evolution and Treatments.

Since the SARS-CoV-2 outbreak, pharmaceutical companies and researchers worldwide have worked hard to develop vaccines and drugs to end the SARS-CoV-2 pandemic. The potential pathogen responsible for Coronavirus Disease 2019 (COVID-19), SARS-CoV-2, belongs to a novel lineage of beta coronaviruses in the subgenus arbovirus. Antiviral drugs, convalescent plasma, monoclonal antibodies, and vaccines are effective treatments for SARS-CoV-2 and are beneficial in preventing infection. Numerous studies have already been conducted using the genome sequence of SARS-CoV-2 in comparison with that of other SARS-like viruses, and numerous treatments/prevention measures are currently undergoing or have already undergone clinical trials. We summarize these studies in depth in the hopes of highlighting some key details that will help us to better understand the viral origin, epidemiology, and treatments of the virus.

Detection of a novel Pestivirus strain in Java ticks (Amblyomma javanense) and the hosts Malayan pangolin (Manis javanica) and Chinese pangolin (Manis pentadactyla).

Pangolins are endangered animals and are listed in the CITES Appendix I of the Convention International Trade Endangered Species of Wild Fauna and Flora as well as being the national first-level protected wild animal in China. Based on a few reports on pangolins infected with pestiviruses of the Flaviviridae family, Pestivirus infections in pangolins have attracted increasing attention. Pangolin pestivirus is a pathogen that may cause diseases such as acute diarrhea and acute hemorrhagic syndrome. To better understand the epidemiology and genomic characterization of pestiviruses carried by pangolins, we detected pestiviruses in dead Malayan pangolin using metavirome sequencing technology and obtained a Pestivirus sequence of 12,333 nucleotides (named Guangdong pangolin Pestivirus, GDPV). Phylogenetic tree analysis based on the entire coding sequence, NS3 gene or RdRp gene sequences, showed that GDPV was closely related to previously reported pangolin-derived Pestivirus and clustered into a separate branch. Molecular epidemiological investigation revealed that 15 Pestivirus-positive tissues from two pangolins individuals with a positivity rate of 5.56%, and six Amblyomma javanense carried pestiviruses with a positivity rate of 19.35%. Moreover, the RdRp gene of the Pestivirus carried by A. javanense showed a high similarity to that carried by pangolins (93-100%), indicating A. javanense is likely to represent the vector of Pestivirus transmission. This study expands the diversity of viruses carried by pangolins and provides an important reference value for interrupting the transmission route of the virus and protecting the health of pangolins.

Specific detection of Angiostrongylus cantonensis in the snail Achatina fulica using a loop-mediated isothermal amplification (LAMP) assay.

Angiostrongylus cantonensis, a rat lungworm, can cause eosinophilic meningitis and angiostrongyliasis in humans following ingestion of contaminated foods or intermediate/paratenic hosts with infective larvae. The snail Achatina fulica is one of the important intermediate hosts of A. cantonensis and is commonly eaten by humans in some countries. In the present study, we developed a loop-mediated isothermal amplification (LAMP) method for the specific detection of A. cantonensis in Ac. fulica. Primers for LAMP were designed based on the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA (rDNA) of A. cantonensis. Specificity tests showed that only the products of A. cantonensis were detected when DNA samples of A. cantonensis and the heterologous control samples Anisakis simplex s.s, Trichuris trichiura, Toxocara canis, Trichinella spiralis and Ascaris lumbricoides were amplified by LAMP. Sensitivity evaluation indicated that the LAMP assay is 10 times more sensitive than the conventional polymerase chain reaction (PCR) assay. The established LAMP assay is rapid, inexpensive and easy to be performed. It can be used in clinical applications for rapid and sensitive detection of A. cantonensis in snails, which has implications for the effective control of angiostrongyliasis.

The complete mitochondrial genomes of three cestode species of Taenia infecting animals and humans.

Mitochondrial (mt) genome sequences provide useful markers for investigating population genetic structures, systematics and phylogenetics of organisms. Although Taenia multiceps, T. hydatigena, and T. taeniaeformis are common taeniid tapeworms of ruminants, pigs, dogs, or cats, causing significant economic losses, no published study on their mt genomes is available. The complete mt genomes of T. multiceps, T. hydatigena, and T. taeniaeformis were amplified in two overlapping fragments and then sequenced. The sizes of the entire mt genome were 13700 bp for T. multiceps, 13489 bp for T. hydatigena, and 13647 bp for T. taeniaeformis. Each of the three genomes contains 36 genes, consisting of 12 genes for proteins, 2 genes for rRNA, and 22 genes for tRNA, which are the same as the mt genomes of all other cestode species studied to date. All genes are transcribed in the same direction and have a nucleotide composition high in A and T. The contents of A+T of the complete genomes are 71.3% for T. multiceps, 70.8% for T. hydatigena, and 73.0% for T. taeniaeformis. The AT bias had a significant effect on both the codon usage pattern and amino acid composition of proteins. T. multiceps and T. hydatigena had two noncoding regions, but T. taeniaeformis had only one. Phylogenetic analyses based on concatenated amino acid sequences of 12 protein-coding genes revealed that T. multiceps, T. hydatigena, and T. taeniaeformis were more closely related to the other members of the Taenia genus, consistent with results of previous morphological and molecular studies. The present study determined the complete mt genome sequences for three Taenia species of animal and human health significance, providing useful markers for studying the systematics, population genetics, and molecular epidemiology of these cestode parasites of animals and humans.

Toxoplasma gondii: protective immunity against experimental toxoplasmosis induced by a DNA vaccine encoding the perforin-like protein 1.

Toxoplasma gondii is an important zoonotic parasite infecting about one third of the world population, causing congenital infections and eye disease. T. gondii perforin-like protein 1 (TgPLP1) is believed to be involved in the acute virulence of T. gondii in mice, and is therefore of interest as a vaccine candidate. In this study, we constructed a DNA vaccine expressing TgPLP1, and evaluated the immune response in Kunming mice. The gene sequence encoding TgPLP1 was inserted into the eukaryotic expression vector pVAX I, and Kunming mice were immunized intramuscularly with the plasmid. After immunization, we evaluated the immune response using lymphoproliferative assay, cytokine and antibody measurements, and the survival times of mice challenged lethally with 1×10(3) tachyzoites of the virulent T. gondii RH strain. The results showed that pVAX/TgPLP1 alone or with pVAX/IL-18 developed specific anti-TLA (T. gondii lysate antigen) antibodies and specific lymphocyte proliferative responses. Co-injection of pVAX/IL-18 significantly increased the production of IFN-γ and IL-2. Further, challenge experiments showed that co-immunization of pVAX/TgPLP1 with pVAX/IL-18 significantly (P<0.05) increased survival time (12.7±1.2days) of immunized mice, compared with pVAX/TgPLP1 alone (11.3±0.9days). These results demonstrate that TgPLP1 is a potential vaccine candidate against toxoplasmosis, worth further evaluation in other animal hosts. IL-18 could enhance the immune effect of TgPLP1, prolonging the survival time of immunized mice.