Schistosoma japonicum EKLF/KLF1 is a potential immune target to tackle schistosomiasis.

BACKGROUND: Interruption of parasite reproduction by targeting migrating schistosomula is a promising strategy for managing schistosomiasis. Hepatic schistosomula proteins previously identified based on second-generation schistosome DNA sequencing were found to hold excellent potential for schistosomiasis japonica diagnosis and as vaccine candidates. However, there are still many unknown schistosomula proteins that warrant further investigations. Herein, a novel schistosomula protein, the Schistosoma japonicum erythroid Krüppel-like factor (SjEKLF/KLF1), was explored. METHODS: Sequence alignment was carried out to detect the amino acid sequence characteristics of SjEKLF. The expression profile of SjEKLF was determined by western blot and immunofluorescence analysis. Enzyme-linked immunosorbent assay was used to determine the antigenicity of SjEKLF in hosts. Mice immunised with recombinant SjEKLF were challenged to test the potential value of the protein as an immunoprotective target. RESULTS: SjEKLF is defined as EKLF/KLF1 for its C-terminal DNA-binding domain. SjEKLF is mainly expressed in hepatic schistosomula and male adults and located within the intestinal intima of the parasites. Notably, high levels of SjEKLF-specific antibodies were detected in host sera and SjEKLF exhibited outstanding sensitivity and specificity for schistosomiasis japonica immunodiagnosis but failed to distinguish between ongoing infection and previous exposure. In addition, SjEKLF immunisation reduced the infection in vivo, resulting in decreased worm and egg counts, and alleviated body weight loss and hepatomegaly in infected mice. CONCLUSIONS: Overall, these findings demonstrate that SjEKLF is critical for the infection of S. japonicum and may be a potential target to help control S. japonicum infection and transmission.

Boeravinone B, a natural rotenoid, inhibits osteoclast differentiation through modulating NF-κB, MAPK and PI3K/Akt signaling pathways.

Osteoporosis is a major public health concern, which requires novel therapeutic strategies to prevent or mitigate bone loss. Natural compounds have attracted attention as potential therapeutic agents due to their safety and efficacy. In this study, we investigated the regulatory activities of boeravinone B (BOB), a natural rotenoid isolated from the medicinal plant Boerhavia diffusa, on the differentiation of osteoclasts and mesenchymal stem cells (MSCs), the two main cell components responsible for bone remodeling. We found that BOB inhibited osteoclast differentiation and function, as determined by TRAP staining and pit formation assay, with no significant cytotoxicity. Furthermore, our results showing that BOB ameliorates ovariectomyinduced bone loss demonstrated that BOB is also effective in vivo. BOB exerted its inhibitory effects on osteoclastogenesis by downregulating the RANKL/RANK signaling pathways, including NF-κB, MAPK, and PI3K/Akt, resulting in the suppression of osteoclast-specific gene expression. Further experiments revealed that, at least phenomenologically, BOB promotes osteoblast differentiation of bone marrow-derived MSCs but inhibits their differentiation into adipocytes. In conclusion, our study demonstrates that BOB inhibits osteoclastogenesis and promotes osteoblastogenesis in vitro by regulating various signaling pathways. These findings suggest that BOB has potential value as a novel therapeutic agent for the prevention and treatment of osteoporosis. [BMB Reports 2023; 56(10): 545-550].

Schistosoma japonicum Tyrosine Hydroxylase is promising targets for immunodiagnosis and immunoprotection of Schistosomiasis japonica.

Identification of promising schistosome antigen targets is crucial for the development of anti-schistosomal strategies. Schistosomes rely on their neuromuscular systems to coordinate important locomotory behaviors. Tyrosine hydroxylase (TH) is critical in the initial rate-limiting step in biosynthesis of catecholamine, the important neuroactive agents, which promote the lengthening of the worm through muscular relaxation and are therefore of great importance to the movement of the organism both within and between its hosts. THs from both Schistosoma mansoni and Schistosoma japonicum and their enzyme activities have been discovered; however, the role of these proteins during infection have not been explored. Herein, a recombinant protein of the nonconserved fragment of S. japonicum TH (SjTH) was produced and the corresponding polyclonal antibody was generated. The expression and antigenicity of SjTH were detected by qRT-PCR, western blotting, immunofluorescence assays, and ELISA. Mice immunized with the recombinant SjTH were challenged with cercariae to evaluate the immunoprotective value of this protein. Our results showed SjTH not only distributed in the head associated with the central nervous system, but also expressed along the tegument and the intestinal intima, which are involved in the movement, coupling and digestion of the parasites and associated with the peripheral nervous system. This protein can effectively stimulate humoral immune responses in mammalian hosts and has high potential as a biomarker for schistosomiasis immunodiagnosis. Furthermore, immunization with recombinant SjTH showed to reduce the worm and egg burden of challenged mice, and to contribute to the systemic balance of the Th1/Th2 responses. Taken together, these results suggest that SjTH is an important pathogenic molecule in S. japonicum and may be a possible target for anti-schistosomal approaches.

Pirfenidone Inhibits Alveolar Bone Loss in Ligature-Induced Periodontitis by Suppressing the NF-κB Signaling Pathway in Mice.

There has been increasing interest in adjunctive use of anti-inflammatory drugs to control periodontitis. This study was performed to examine the effects of pirfenidone (PFD) on alveolar bone loss in ligature-induced periodontitis in mice and identify the relevant mechanisms. Experimental periodontitis was established by ligating the unilateral maxillary second molar for 7 days in mice (n = 8 per group), and PFD was administered daily via intraperitoneal injection. The micro-computed tomography and histology analyses were performed to determine changes in the alveolar bone following the PFD administration. For in vitro analysis, bone marrow macrophages (BMMs) were isolated from mice and cultured with PFD in the presence of RANKL or LPS. The effectiveness of PFD on osteoclastogenesis, inflammatory cytokine expression, and NF-κB activation was determined with RT-PCR, Western blot, and immunofluorescence analyses. PFD treatment significantly inhibited the ligature-induced alveolar bone loss, with decreases in TRAP-positive osteoclasts and expression of inflammatory cytokines in mice. In cultured BMM cells, PFD also inhibited RANKL-induced osteoclast differentiation and LPS-induced proinflammatory cytokine (IL-1ß, IL-6, TNF-a) expression via suppressing the NF-κB signal pathway. These results suggest that PFD can suppress periodontitis progression by inhibiting osteoclastogenesis and inflammatory cytokine production via inhibiting the NF-κB signal pathway, and it may be a promising candidate for controlling periodontitis.

Novel Hepatic Schistosomula Antigens as Promising Targets for Immunodiagnosis and Immunoprotection of Schistosomiasis japonica.

BACKGROUND: Antigens of migrating schistosomula are promising candidates as schistosomiasis vaccine targets, since immune attack on hepatic schistosomula would interrupt the parasites life cycle and reduce egg burden on the host. METHODS: In this study, we report a collection of Schistosoma japonicum schistosomula proteins (SjScPs) that are highly expressed in hepatic schistosomula. The expression characteristics, antigenicity and immune protection of these proteins were studied by western blot, ELISA, immunofluorescence and challenge assays. RESULTS: We found that several of these SjScPs were highly antigenic and could effectively stimulate humoral immune responses in both human and other mammalian hosts. In particular, SjScP25, SjScP37, SjScP41, SjScP80, and SjScP88 showed high potential as biomarkers for schistosomiasis immunodiagnosis. Furthermore, we demonstrated that immunization with several of the recombinant SjScPs were able to protect mice from S japonicum challenge infection, with SjScP25 generating the most protective results. CONCLUSIONS: Our work represents a group of novel schistosome immunogens, which may be promising schistosomiasis japonica diagnosis and vaccine candidates.

A Novel Thioredoxin-Like Protein of Babesia microti Involved in Parasite Pathogenicity.

Babesiosis poses a serious threat to immunocompromised individuals and the major etiological species of Babesia for human babesiosis is Babesia microti. Merozoites are a critical stage in the life cycle of Babesia microti. Several merozoite proteins have been demonstrated to play important roles in this process; however, most of the merozoite proteins of B. microti remain unknown. In the present study, we identified a novel merozoite protein of B. microti with similar structure to the thioredoxin (Trx)-like domain of the Trx family, which was named as B. microti Trx-like protein (BmTLP). Western blot assays demonstrated that this protein was expressed by B. microti during the erythrocytic infection process, and its expression peaked on day 7 post-infection in vivo. Immunofluorescence assay further showed that this protein is mainly expressed in B. microti merozoites. BmTLP hold both heparin- and erythrocyte-binding properties, which are critical functions of invasion-related proteins. Immunization with recombinant BmTLP imparted significant protection against B. microti infection in mice. Taken together, these results suggest that the novel merozoite protein, BmTLP, is an important pathogenic molecule of B. microti and may be a possible target for the design of babesiosis control strategy.

Isolation of High Purity Mouse Mesenchymal Stem Cells through Depleting Macrophages Using Liposomal Clodronate.

BACKGROUND: The use of mouse bone marrow mesenchymal stem cells (mBMSCs) represents a promising strategy for performing preclinical studies in the field of cell-based regenerative medicine; however, mBMSCs obtained via conventional isolation methods have two drawbacks, i.e., (i) they are heterogeneous due to frequent macrophage contamination, and (ii) they require long-term culturing for expansion. METHODS: In the present study, we report a novel strategy to generate highly pure mBMSCs using liposomal clodronate. This approach is based on the properties of the two cell populations, i.e., BMSCs (to adhere to the plasticware in culture dishes) and macrophages (to phagocytose liposomes). RESULTS: Liposomal clodronate added during the first passage of whole bone marrow culture was selectively engulfed by macrophages in the heterogeneous cell population, resulting in their effective elimination without affecting the MSCs. This method allowed the generation of numerous high-purity Sca-1+CD44+F4/80- mBMSCs (> 95%) with just one passaging. Comparative studies with mBMSCs obtained using conventional methods revealed that the mBMSCs obtained in the present study had remarkably improved experimental utilities, as demonstrated by in vitro multilineage differentiation and in vivo ectopic bone formation assays. CONCLUSION: Our newly developed method, which enables the isolation of mBMSCs using simple and convenient protocol, will aid preclinical studies based on the use of MSCs.

Merozoite Proteins Discovered by qRT-PCR-Based Transcriptome Screening of Plasmodium falciparum.

The development of malaria vaccines and medicines depends on the discovery of novel malaria protein targets, but the functions of more than 40% of P. falciparum genes remain unknown. Asexual parasites are the critical stage that leads to serious clinical symptoms and that can be modulated by malaria treatments and vaccines. To identify critical genes involved in the development of Plasmodium parasites within erythrocytes, the expression profile of more than 5,000 genes distributed across the 14 chromosomes of the PF3D7 strain during its six critical developmental stages (merozoite, early-ring, late-ring, early trophozoite, late-trophozoite, and middle-schizont) was evaluated. Hence, a qRT-PCR-based transcriptome of the erythrocytic developmental process of P. falciparum was revealed. Weighted gene coexpression network analyses revealed that a large number of genes are upregulated during the merozoite release process. Further gene ontology analysis revealed that a cluster of genes is associated with merozoite and may be apical complex components. Among these genes, 135 were comprised within chromosome 14, and 80% of them were previously unknown in functions. Western blot and immunofluorescence assays using newly developed corresponding antibodies showed that some of these newly discovered proteins are highly expressed in merozoites. Further invasion inhibition assays revealed that specific antibodies against several novel merozoite proteins can interfere with parasite invasion. Taken together, our study provides a developmental transcriptome of the asexual parasites of P. falciparum and identifies a group of previously unknown merozoite proteins that may play important roles in the process of merozoite invasion.

MicroRNAs Related to Cognitive Impairment After Hearing Loss.

OBJECTIVES: Our research group has previously demonstrated that hearing loss might be a risk factor for synaptic loss within the hippocampus and impairment of cognition using an animal model of Alzheimer disease. In this study, after inducing hearing loss in a rat model of Alzheimer disease, the associations of various microRNAs (miRNAs) with cognitive impairment were investigated. METHODS: Rats were divided randomly into two experimental groups: the control group, which underwent sham surgery and subthreshold amyloid-ß infusion and the deaf group, which underwent bilateral cochlear ablation and subthreshold amyloid-ß infusion. All rats completed several cognitive function assessments 11 weeks after surgery, including the object-in-place task (OPT), the novel object recognition task (NOR), the object location task (OLT), and the Y-maze test. After the rats completed these tests, hippocampus tissue samples were assessed using miRNA microarrays. Candidate miRNAs were selected based on the results and then validated with quantitative reverse transcriptionpolymerase chain reaction (qRT-PCR) analyses. RESULTS: The deaf group showed considerably lower scores on the OPT, OLT, and Y-maze test than the control group. The microarray analysis revealed that miR-29b-3p, -30e-5p, -153-3p, -376a-3p, -598-3p, -652-5p, and -873-3p were candidate miRNAs, and qRT-PCR showed significantly higher levels of miR-376a-3p and miR-598-3p in the deaf group. CONCLUSION: These results indicate that miR-376a-3p and miR-598-3p were related to cognitive impairment after hearing loss.

Duplex real-time PCR for sexing Schistosoma japonicum cercariae based on W chromosome-specific genes and its applications.

As a unique feature among otherwise hermaphroditic trematodes, Schistosoma species are gonochoric parasites whose sex is genetically determined (ZZ for males and ZW for females). However, schistosome larvae are morphologically identical, and sex can only be discriminated by molecular methods. Here, we integrated published Schistosoma. japonicum transcriptome and genome data to identify W chromosome-specific genes as sex biomarkers. Three W chromosome-specific genes of S. japonicum were identified as sex biomarkers from a panel of 12 genes expressed only in females. An efficient duplex real-time PCR (qPCR) method for sexing cercariae was developed which could identify the sex of cercariae within 2 h without DNA extraction. Moreover, this method can be used to identify not only single-sex but also mixed-sex schistosome-infected snails. We observed a nearly equal proportion of single-male, single-female, and mixed-sex schistosome infections in artificially infected snails. Sex-known schistosome-infected snail models can be efficiently constructed with the aid of duplex qPCR. A field study revealed that single-sex schistosome infections were predominant among naturally infected snails. Finally, a schistosomiasis mouse model based on sex-known cercariae infection was shown to be more reliable than a model based on sex-unknown cercariae infection. The developed duplex qPCR method for sexing S. japonicum cercariae can be widely used for schistosomiasis modeling, genetic experiments, and field-based molecular epidemiological studies.

Low-Complexity Repetitive Epitopes of Plasmodium falciparum Are Decoys for Humoural Immune Responses.

Induction of humoural immunity is critical for clinical protection against malaria. More than 100 malaria vaccine candidates have been investigated at different developmental stages, but with limited protection. One of the roadblocks constrains the development of malaria vaccines is the poor immunogenicity of the antigens. The objective of this study was to map the linear B-cell epitopes of the Plasmodium falciparum erythrocyte invasion-associated antigens with a purpose of understanding humoural responses and protection. We conducted a large-scale screen using overlapping peptide microarrays of 37 proteins from the P. falciparum parasite, most of which are invasion-associated antigens which have been tested in clinical settings as vaccine candidates, with sera from individuals with various infection episodes. Analysis of the epitome of the antigens revealed that the most immunogenic epitopes were predominantly located in the low-complexity regions of the proteins containing repetitive and/or glutamate-rich motifs in different sequence contexts. However, in vitro assay showed the antibodies specific for these epitopes did not show invasion inhibitory effect. These discoveries indicated that the low-complexity regions of the parasite proteins might drive immune responses away from functional domains, which may be an instructive finding for the rational design of vaccine candidates.

CUEDC2 controls osteoblast differentiation and bone formation via SOCS3-STAT3 pathway.

The CUE domain-containing 2 (CUEDC2) protein plays critical roles in many biological processes, such as the cell cycle, inflammation, and tumorigenesis. However, whether CUEDC2 is involved in osteoblast differentiation and plays a role in bone regeneration remains unknown. This study investigated the role of CUEDC2 in osteogenesis and its underlying molecular mechanisms. We found that CUEDC2 is expressed in bone tissues. The expression of CUEDC2 decreased during bone development and BMP2-induced osteoblast differentiation. The overexpression of CUEDC2 suppressed the osteogenic differentiation of precursor cells, while the knockdown of CUEDC2 showed the opposite effect. In vivo studies showed that the overexpression of CUEDC2 decreased bone parameters (bone volume, bone area, and bone mineral density) during ectopic bone formation, whereas its knockdown increased bone volume and the reconstruction percentage of critical-size calvarial defects. We found that CUEDC2 affects STAT3 activation by regulating SOCS3 protein stability. Treatment with a chemical inhibitor of STAT3 abolished the promoting effect of CUEDC2 silencing on osteoblast differentiation. Together, we suggest that CUEDC2 functions as a key regulator of osteoblast differentiation and bone formation by targeting the SOCS3-STAT3 pathway. CUEDC2 manipulation could serve as a therapeutic strategy for controlling bone disease and regeneration.

Axonal sprouting in the dorsal cochlear nucleus affects gap­prepulse inhibition following noise exposure.

One of the primary theories of the pathogenesis of tinnitus involves maladaptive auditory­somatosensory plasticity in the dorsal cochlear nucleus (DCN), which is assumed to be due to axonal sprouting. Although a disrupted balance between auditory and somatosensory inputs may occur following hearing damage and may induce tinnitus, examination of this phenomenon employed a model of hearing damage that does not account for the causal relationship between these changes and tinnitus. The present study aimed to investigate changes in auditory­somatosensory innervation and the role that axonal sprouting serves in this process by comparing results between animals with and without tinnitus. Rats were exposed to a noise­inducing temporary threshold shift and were subsequently divided into tinnitus and non­tinnitus groups based on the results of gap prepulse inhibition of the acoustic startle reflex. DCNs were collected from rats divided into three sub­groups according to the number of weeks (1, 2 or 3) following noise exposure, and the protein levels of vesicular glutamate transporter 1 (VGLUT1), which is associated with auditory input to the DCN, and VGLUT2, which is in turn primarily associated with somatosensory inputs, were assessed. In addition, factors related to axonal sprouting, including growth­associated protein 43 (GAP43), postsynaptic density protein 95, synaptophysin, α­thalassemia/mental retardation syndrome X­linked homolog (ATRX), growth differentiation factor 10 (GDF10), and leucine­rich repeat and immunoglobulin domain­containing 1, were measured by western blot analyses. Compared to the non­tinnitus group, the tinnitus group exhibited a significant decrease in VGLUT1 at 1 week and a significant increase in VGLUT2 at 3 weeks post­exposure. In addition, rats in the tinnitus group exhibited significant increases in GAP43 and GDF10 protein expression levels in their DCN at 3 weeks following noise exposure. Results from the present study provided further evidence that changes in the neural input distribution to the DCN may cause tinnitus and that axonal sprouting underlies these alterations.

A Parallel Comparison of Antigen Candidates for Development of an Optimized Serological Diagnosis of Schistosomiasis Japonica in the Philippines.

Schistosoma japonicum is stubbornly persistent in China and the Philippines. Fast and accurate diagnostic tools are required to monitor effective control measures against schistosomiasis japonica. Promising antigen candidates for the serological diagnosis of schistosomiasis japonica have generally been identified from the Chinese strain of S. japonicum. However, the Chinese (SjC) and Philippine (SjP) strains of S. japonicum express a number of clear phenotypic differences, including aspects of host immune responses. This feature thereby emphasized the requirement to determine whether antigens identified as having diagnostic value for SjC infection are also suitable for the diagnosis of SjP infection. In the current study, 10 antigens were selected for comparison of diagnostic performance of the SjP infection using ELISA. On testing of sera from 180 subjects in the Philippines, SjSAP4 exhibited the best diagnostic performance with 94.03% sensitivity and 98.33% specificity using an optimized serum dilution. In another large scale testing with 412 serum samples, a combination (SjSAP4+Sj23-LHD (large hydrophilic domain)) provided the best diagnostic outcome with 87.04% sensitivity and 96.67% specificity. This combination could be used in future for serological diagnosis of schistosomiasis in the Philippines, thereby representing an important component for monitoring integrated control measures.

Down-Regulation of Tim-3 in Monocytes and Macrophages in Plasmodium Infection and Its Association with Parasite Clearance.

T-cell immunoglobulin and mucin-domain-containing molecule 3 (Tim-3) has complicated roles in regulating monocytes and macrophages in various diseases and it tends to be an inhibitory molecule to facilitate the immune escape of parasites in malaria. However, the mechanisms of Tim-3 mediated responses in monocytes and macrophages in malaria have not been clear. In this study, we found that Plasmodium infection down-regulated Tim-3 expression in peripheral monocytes of patients suffering from Plasmodium falciparum malaria and in splenic macrophages of Plasmodium berghei ANKA-infected mice. Tim-3 signal blockade with anti-Tim-3 antibodies enhanced phagocytosis and parasitical mediator production of murine splenic macrophages during Plasmodium infection. In conclusion, Tim-3 constricts monocytes/macrophages activity, and anti-Tim-3 treatment facilitates parasite clearance, especially in the early stage of Plasmodium infection.

Genome-Wide Transcriptome Analysis Reveals Extensive Alternative Splicing Events in the Protoscoleces of Echinococcus granulosus and Echinococcus multilocularis.

Alternative splicing (AS), as one of the most important topics in the post-genomic era, has been extensively studied in numerous organisms. However, little is known about the prevalence and characteristics of AS in Echinococcus species, which can cause significant health problems to humans and domestic animals. Based on high-throughput RNA-sequencing data, we performed a genome-wide survey of AS in two major pathogens of echinococcosis-Echinococcus granulosus and Echinococcus multilocularis. Our study revealed that the prevalence and characteristics of AS in protoscoleces of the two parasites were generally consistent with each other. A total of 6,826 AS events from 3,774 E. granulosus genes and 6,644 AS events from 3,611 E. multilocularis genes were identified in protoscolex transcriptomes, indicating that 33-36% of genes were subject to AS in the two parasites. Strikingly, intron retention instead of exon skipping was the predominant type of AS in Echinococcus species. Moreover, analysis of the Kyoto Encyclopedia of Genes and Genomes pathway indicated that genes that underwent AS events were significantly enriched in multiple pathways mainly related to metabolism (e.g., purine, fatty acid, galactose, and glycerolipid metabolism), signal transduction (e.g., Jak-STAT, VEGF, Notch, and GnRH signaling pathways), and genetic information processing (e.g., RNA transport and mRNA surveillance pathways). The landscape of AS obtained in this study will not only facilitate future investigations on transcriptome complexity and AS regulation during the life cycle of Echinococcus species, but also provide an invaluable resource for future functional and evolutionary studies of AS in platyhelminth parasites.

A next-generation microarray further reveals stage-enriched gene expression pattern in the blood fluke Schistosoma japonicum.

BACKGROUND: Schistosomiasis is caused by infection with blood flukes of the genus Schistosoma, and ranks, in terms of disability-adjusted life years (DALYs), as the third most important neglected tropical disease. Schistosomes have several discrete life stages involving dramatic morphological changes during their development, which require subtle gene expression modulations to complete the complex life-cycle. RESULTS: In the current study, we employed a second generation schistosome DNA chip printed with the most comprehensive probe array for studying the Schistosoma japonicum transcriptome, to explore stage-associated gene expression in different developmental phases of S. japonicum. A total of 328, 95, 268 and 532 mRNA transcripts were enriched in cercariae, hepatic schistosomula, adult worms and eggs, respectively. In general, genes associated with transcriptional regulation, cell signalling and motor activity were readily expressed in cercariae; the expression of genes involved in neuronal activities, apoptosis and renewal was modestly upregulated in hepatic schistosomula; transcripts involved in egg production, nutrition metabolism and glycosylation were enriched in adult worms; while genes involved in cell division, microtubule-associated mobility, and host-parasite interplay were relatively highly expressed in eggs. CONCLUSIONS: The study further highlights the expressional features of stage-associated genes in schistosomes with high accuracy. The results provide a better perspective of the biological characteristics among different developmental stages, which may open new avenues for identification of novel vaccine candidates and the development of novel control interventions against schistosomiasis.

T-Cell Immunoglobulin- and Mucin-Domain-Containing Molecule 3 Signaling Blockade Improves Cell-Mediated Immunity Against Malaria.

Cell-mediated immune responses play important roles in immune protection against Plasmodium infection. However, impaired immunity, such as lymphocyte exhaustion, is a common phenomenon in malaria. T-cell immunoglobulin- and mucin-domain-containing molecule 3 (Tim-3) is an important regulatory molecule in cell-mediated immunity and has been implicated in malaria. In this study, it was found that Tim-3 expression on key populations of lymphocytes was significantly increased in both Plasmodium falciparum-infected patients and Plasmodium berghei ANKA (PbANKA)-infected C57BL/6 mice. Upregulation of Tim-3 led to lymphocyte exhaustion, while blocking Tim-3 signaling with an anti-Tim-3 antibody restored lymphocyte activity in Plasmodium infections. Further, anti-Tim-3 treatment accelerated the parasite clearance and relieved the symptoms of cerebral malaria in PbANKA-infected mice. In conclusion, Tim-3 on immune cells negatively regulates cell-mediated immunity against Plasmodium infection, and blocking Tim-3 signaling enhances sterile immunity and may play a protective role during malarial parasite infections.

Saposin-like Proteins, a Multigene Family of Schistosoma Species, are Biomarkers for the Immunodiagnosis of Schistosomiasis Japonica.

BACKGROUND: One major obstacle to schistosomiasis prevention and control is the lack of accurate and sensitive diagnostic approaches, which are essential for planning, targeting, and evaluating disease control efforts. METHODS: Based on bioinformatics analysis, we identified a multigene family of saposin-like protein (SAPLP) in the schistosome genomes. Schistosoma japonicum SAPLPs (SjSAPLPs), including recently reported promising biomarker SjSP-13, were systematically and comparatively assessed as immunodiagnostic antigens for schistosomiasis japonica. RESULTS: Two novel antigens (SjSAPLP4 and SjSAPLP5) could specifically react to serum samples from both S. japonicum-infected laboratory animals and patients. The sensitivities of SjSAPLP4, SjSAPLP5, and SjSP-13 for immunodiagnosis were 98% (95% confidence interval, 88.0%-99.9%), 96% (85.1%-99.3%), and 88% (75.0%-95.0%), respectively, and 100% (91.1%-100%) specificity was observed for the 3 antigens with enzyme-linked immunosorbent assay; there was no cross-reaction with clonorchiosis (0 of 19 patients), echinococcosis (0 of 20 patients), or trichinellosis (0 of 18 patients) for the 3 antigens. Antibodies to the 3 antigens could be detected in the serum samples of rabbits infected with 1000 cercariae as early as 3-4 weeks after infection. CONCLUSIONS: These results suggest that SjSAPLP4 and SjSAPLP5 could serve as novel biomarkers for the immunodiagnosis of schistosomiasis japonica, which will further improve diagnostic sensitivity and specificity.