Major gaps in our understanding of Plasmodium vivax biology and the acquisition of immunity to this parasite hinder vaccine development. P. vivax merozoites exclusively invade reticulocytes, making ...parasite proteins that mediate reticulocyte binding and/or invasion potential key vaccine or drug targets. While protein interactions that mediate invasion are still poorly understood, the P. vivax Reticulocyte-Binding Protein family (PvRBP) is thought to be involved in P. vivax restricted host-cell selectivity.
We assessed the binding specificity of five members of the PvRBP family (PvRBP1a, PvRBP1b, PvRBP2a, PvRBP2b, PvRBP2-P2 and a non-binding fragment of PvRBP2c) to normocytes or reticulocytes. PvRBP2b was identified as the only reticulocyte-specific binder (P<0.001), whereas the others preferentially bound to normocytes (PvRBP1a/b P≤0.034), or showed comparable binding to both (PvRBP2a/2-P2, P = 0.38). Furthermore, we measured levels of total and IgG subclasses 1, 2, 3 and 4 to the six PvRBPs in a cohort of young Papua New Guinean children, and assessed their relationship with prospective risk of P. vivax malaria. Children had substantial, highly correlated (rho = 0.49-0.82, P<0.001) antibody levels to all six PvRBPs, with dominant IgG1 and IgG3 subclasses. Both total IgG (Incidence Rate Ratio IRR 0.63-0.73, P = 0.008-0.041) and IgG1 (IRR 0.56-0.69, P = 0.001-0.035) to PvRBP2b and PvRBP1a were strongly associated with reduced risk of vivax-malaria, independently of age and exposure.
These results demonstrate a diversity of erythrocyte-binding phenotypes of PvRBPs, indicating binding to both reticulocyte-specific and normocyte-specific ligands. Our findings provide further insights into the naturally acquired immunity to P. vivax and highlight the importance of PvRBP proteins as targets of naturally acquired humoral immunity. In-depth studies of the role of PvRBPs in P. vivax invasion and functional validation of the role of anti-PvRBP antibodies in clinical immunity against P. vivax are now required to confirm the potential of the reticulocyte-binding PvRBP2b and PvRBP1a as vaccine candidate antigens.
Plasmodium falciparum parasites in the merozoite stage invade human erythrocytes and cause malaria. Invasion requires multiple interactions between merozoite ligands and erythrocyte receptors. ...P. falciparum reticulocyte binding homolog 5 (PfRh5) forms a complex with the PfRh5-interacting protein (PfRipr) and Cysteine-rich protective antigen (CyRPA) and binds erythrocytes via the host receptor basigin. However, the specific role that PfRipr and CyRPA play during invasion is unclear. Using P. falciparum lines conditionally expressing PfRipr and CyRPA, we show that loss of PfRipr or CyRPA function blocks growth due to the inability of merozoites to invade erythrocytes. Super-resolution microscopy revealed that PfRipr, CyRPA, and PfRh5 colocalize at the junction between merozoites and erythrocytes during invasion. PfRipr, CyRPA, and PfRipr/CyRPA/PfRh5-basigin complex is required for triggering the Ca2+ release and establishing the tight junction. Together, these results establish that the PfRh5/PfRipr/CyRPA complex is essential in the sequential molecular events leading to parasite invasion of human erythrocytes.
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•P. falciparum PfRh5-binding partners PfRipr and CyRPA are essential for merozoite invasion•PfRipr and CyRPA are linked to release of calcium into the erythrocyte•PfRh5/PfRipr/CyRPA complex binding to host receptor basigin is required for Ca2+ release•PfRh5/PfRipr/CyRPA complex forms at the interface between the merozoite and erythrocyte
Plasmodium falciparum PfRipr and CyRPA form a complex with PfRh5, which mediates erythrocyte invasion. The specific role of PfRipr and CyRPA is unclear. Volz et al. (2016) show that PfRipr and CyRPA are essential for invasion and required for Ca2+ release during the sequential molecular events for invasion of erythrocytes.
shows a strict host tropism for reticulocytes. We identified transferrin receptor 1 (TfR1) as the receptor for
reticulocyte-binding protein 2b (PvRBP2b). We determined the structure of the N-terminal ...domain of PvRBP2b involved in red blood cell binding, elucidating the molecular basis for TfR1 recognition. We validated TfR1 as the biological target of PvRBP2b engagement by means of TfR1 expression knockdown analysis. TfR1 mutant cells deficient in PvRBP2b binding were refractory to invasion of
but not to invasion of
Using Brazilian and Thai clinical isolates, we show that PvRBP2b monoclonal antibodies that inhibit reticulocyte binding also block
entry into reticulocytes. These data show that TfR1-PvRBP2b invasion pathway is critical for the recognition of reticulocytes during
invasion.
Solid state zinc ion batteries (ZIBs) and aluminum ion batteries (AIBs) are deemed as promising candidates for supplying power in wearable devices due to merits of low-cost, high safety, and tunable ...flexibility. However, their wide-scale practical application is limited by various challenges, down to the material level. This review begins with elaboration of the root causes and their detrimental effect for four main limitations: electrode-electrolyte interface contact, electrolyte ionic conductivity, mechanical strength and electrolyte voltage stability window. Thereafter, various strategies to mitigate each of the described limitation are discussed along with future research direction perspectives. Finally, to estimate the viability of these technologies for wearable applications, economic-performance metrics are compared against Li-ion batteries.
Objective
To evaluate the extent to which Benign Paroxysmal Positional Vertigo (BPPV) is associated with a higher prevalence of depression and anxiety in patients.
Data Sources
Three databases ...including PubMed, Embase, and The Cochrane Library were searched by two independent authors from inception to June 12, 2022 for observational studies and randomized controlled trials investigating the association between BPPV and depression and anxiety. We included studies published as full‐length articles in peer‐reviewed journals with an adult population aged at least 18 years who have BPPV, detected through validated clinical methods like clinical diagnosis, interview and Dix‐Hallpike test.
Results
A total of 23 articles met the final inclusion criteria and 19 articles were included in the meta‐analysis. BPPV was associated with a 3.19 increased risk of anxiety compared to controls, and 27% (17%–39%) of BPPV patients suffered from anxiety. Furthermore, the weighted average Beck's Anxiety Inventory score was 18.38 (12.57; 24.18), while the weighted average State–Trait Anxiety Index score was 43.08 (37.57; 48.60).
Conclusion
There appears to be some association between BPPV and anxiety, but further studies are required to confirm these associations. Laryngoscope, 134:526–534, 2024
This study aims evaluate the extent to which Benign Paroxysmal Positional Vertigo (BPPV) is associated with a higher prevalence of anxiety and depression in patients. There appears to be some association between BPPV and anxiety, but further studies are required to confirm this association.
Understanding how malaria parasites gain entry into human red blood cells is essential for developing strategies to stop blood stage infection. Plasmodium vivax preferentially invades reticulocytes, ...which are immature red blood cells. The organism has two erythrocyte-binding protein families: namely, the Duffy-binding protein (PvDBP) and the reticulocyte-binding protein (PvRBP) families. Several members of the PvRBP family bind reticulocytes, specifically suggesting a role in mediating host cell selectivity of P. vivax. Here, we present, to our knowledge, the first high-resolution crystal structure of an erythrocyte-binding domain from PvRBP2a, solved at 2.12 Å resolution. The monomeric molecule consists of 10 α-helices and one short β-hairpin, and, although the structural fold is similar to that of PfRh5—the essential invasion ligand in Plasmodium falciparum—its surface properties are distinct and provide a possible mechanism for recognition of alternate receptors. Sequence alignments of the crystallized fragment of PvRBP2a with other PvRBPs highlight the conserved placement of disulfide bonds. PvRBP2a binds mature red blood cells through recognition of an erythrocyte receptor that is neuraminidase- and chymotrypsin-resistant but trypsin-sensitive. By examining the patterns of sequence diversity within field isolates, we have identified and mapped polymorphic residues to the PvRBP2a structure. Using mutagenesis, we have also defined the critical residues required for erythrocyte binding. Characterization of the structural features that govern functional erythrocyte binding for the PvRBP family provides a framework for generating new tools that block P. vivax blood stage infection.
The most severe form of malaria in humans is caused by the protozoan parasite Plasmodium falciparum. The invasive form of malaria parasites is termed a merozoite and it employs an array of parasite ...proteins that bind to the host cell to mediate invasion. In Plasmodium falciparum, the erythrocyte binding-like (EBL) and reticulocyte binding-like (Rh) protein families are responsible for binding to specific erythrocyte receptors for invasion and mediating signalling events that initiate active entry of the malaria parasite. Here we have addressed the role of the cytoplasmic tails of these proteins in activating merozoite invasion after receptor engagement. We show that the cytoplasmic domains of these type 1 membrane proteins are phosphorylated in vitro. Depletion of PfCK2, a kinase implicated to phosphorylate these cytoplasmic tails, blocks P. falciparum invasion of red blood cells. We identify the crucial residues within the PfRh4 cytoplasmic domain that are required for successful parasite invasion. Live cell imaging of merozoites from these transgenic mutants show they attach but do not penetrate erythrocytes implying the PfRh4 cytoplasmic tail conveys signals important for the successful completion of the invasion process.
Highlights • Genomic and transcriptomic data have uncovered an intrinsic apoptosis pathway in schistosomes. • The schistosome intrinsic apoptosis pathway is similar to that in mammals. • Apoptosis is ...active throughout the schistosome life cycle. • Drugs that activate apoptosis in schistosomes may provide a new strategy to combat schistosomiasis.
Human parainfluenza virus type 1 (hPIV1) and 3 (hPIV3) cause seasonal epidemics, but little is known about their interaction with human airway cells. In this study, we determined cytopathology, ...replication, and progeny virion release from human airway cells during long-term infection in vitro. Both viruses readily established persistent infection without causing significant cytopathic effects. However, assembly and release of hPIV1 rapidly declined in sharp contrast to hPIV3 due to impaired viral ribonucleocapsid (vRNP) trafficking and virus assembly. Transcriptomic analysis revealed that both viruses induced similar levels of type I and III IFNs. However, hPIV1 induced specific ISGs stronger than hPIV3, such as MX2, which bound to hPIV1 vRNPs in infected cells. In addition, hPIV1 but not hPIV3 suppressed genes involved in lipid biogenesis and hPIV1 infection resulted in ubiquitination and degradation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a rate limiting enzyme in cholesterol biosynthesis. Consequently, formation of cholesterol-rich lipid rafts was impaired in hPIV1 infected cells. These results indicate that hPIV1 is capable of regulating cholesterol biogenesis, which likely together with ISGs contributes to establishment of a quiescent infection.
•This is the first systematic review and meta-analysis to assess CBI use in RM-NPC.•EBV-specific CTL and DC second/subsequent line monotherapy have good safety profiles.•CBI combination ...therapy/first-line monotherapy may be evaluated with more studies.
Recurrent/Metastatic Nasopharyngeal Carcinoma (RM-NPC) remains difficult to treat and contributes to considerable mortality. The first-line treatment for RM-NPC is Gemcitabine and Cisplatin and second-line treatment options differ. The endemic variant of NPC is associated with Epstein-Barr Virus (EBV). Therefore, Cell-based Immunotherapy (CBI) targeting EBV-specific RM-NPC may be effective.
We systematically searched PubMed, Embase and the Cochrane Library for randomised or observational studies investigating the efficacy and safety of CBI in the treatment of RM-NPC. We performed all meta-analyses using the random-effects model. Studies were further stratified by endemicity, nature of disease and drug type to investigate for potential between-study heterogeneity and additional pre-specified tests were employed to assess for publication bias.
We screened 1,671 studies and included 13 studies with 403 participants in the systematic review, of which nine studies were eligible for meta-analysis. The use of CBI monotherapy as second or subsequent line treatment for EBV-positive RM-NPC revealed an ORR of 10 % (95 %CI = 3 %–29 %), median PFS of 2.37 months (95 %CI = 1.23–3.51) and median OS of 10.16 months (95 %CI = 0.67–19.65). For EBV-specific Cytotoxic T-Lymphocyte monotherapy, the pooled PD rate was 54 % (95 %CI = 9 %–93 %), SD rate was 22 % (95 %CI = 2 %–75 %) and incidence rate of any grade adverse events was 45 %. For Dendritic Cell monotherapy, a PD rate of 80 % (95 % CI = 29 %–98 %), SD rate of 11 % (95 % CI = 0 %–82 %) and incidence rate of any grade adverse events of 29 % was achieved.
CBI monotherapy demonstrates some activity in pre-treated RM-NPC. More trials are needed to better understand how to integrate CBI into RM-NPC care.
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