The Plasmodium falciparum Merozoite Surface Protein 1(Pf MSP1), a predominant antigen on the surface of the asexual blood stage of the parasite, plays a role in erythrocyte invasion. It elicits immune responses during exposure to natural P. falciparum infections, hence, it is a potential vaccine candidate. However, its extensive sequence diversity causes antigenic variability. Parasites that express variants other than that targeted by immune protection mounted as a result of a vaccine variant, evade the resultant host immune protection. This compromises the efficacy of allele-specific vaccines formulated to protect against a single variant. Due to this, Pf MSP1 has been extensively studied, including in Kenya. However, the extent of Pf MSP1 diversity in children with multiple infections are unknown in Kilifi which is a moderate to high malaria transmission zone. Parasite genomic DNA was extracted from 421 blood samples in 33 children aged below 5 years who had at least 9 multiple infections. ...

The roles of allelic and conserved epitopes in vaccine-induced immunity to the C-terminal 42-kDa fragment of the Plasmodium falciparum merozoite surface protein 1 (MSP1) were investigated. The C-terminal fragment of MSP1 was expressed as a baculovirus recombinant protein, BVp42. Rabbits were immunized with BVp42, and antibodies were tested for reactivity to MSP1s of the homologous and heterologous allelic forms, represented by the FUP, FVO, FC27, and Honduras parasite isolates, by enzyme-linked immunosorbent assay and indirect immunofluorescence antibody assay. Despite the fact that allelic sequences accounted for approximately 50% of the BVp42 molecule, anti-BVp42 antibodies cross-reacted extensively with parasites carrying heterologous MSP1 alleles. Enzyme-linked immunosorbent inhibition assays confirmed that an overwhelming majority of the anti-BVp42 antibodies were cross-reactive, suggesting that determinants within conserved block 17 are dominant B-cell epitopes in the anti-BVp42 response. ...

Many studies on the role of merozoite surface protein 3 (MSP3) in immunity against malaria have focused on a conserved section of MSP3. New evidence suggests that polymorphic sequences within MSP3 are under immune selection. We report a detailed analysis of naturally-acquired antibodies to allele-specific and conserved parts of MSP3 in a Kenyan cohort. Indirect and competition ELISA to heterologous recombinant MSP3 proteins were used for antibody assays, and parasites were genotyped for msp3 alleles. Antibody reactivity to allele-specific and conserved epitopes of MSP3 was heterogeneous between individuals. Overall, the prevalence of allele-specific antibody reactivity was significantly higher (3D7-specific 54%, K1-specific 41%) than that to a recombinant protein representing a conserved portion of C-terminal MSP3 (24%, P | 0.01). The most abundant IgG subclass was IgG3, followed by IgG1. Allele-specific reactivity to the K1-type of MSP3 was associated with a lower risk of clinical malaria episodes

MSP1 processing-inhibitory antibodies bind to epitopes on the 19 kDa C-terminal region of the Plasmodium falciparum merozoite surface protein 1 (MSP119), inhibiting erythrocyte invasion. Blocking antibodies also bind to this antigen but prevent inhibitory antibodies binding, allowing invasion to proceed. Recombinant MSP119 had been modified previously to allow inhibitory but not blocking antibodies to continue to bind. Immunization with these modified proteins, therefore, has the potential to induce more effective protective antibodies. However, it was unclear whether the modification of MSP119 would affect critical T-cell responses to epitopes in this antigen. The cellular responses to wild-type MSP119 and a panel of modified MSP119 antigens were measured using an in-vitro assay for two groups of individuals: the first were malaria-naïve and the second had been naturally exposed to Plasmodium falciparum infection. The cellular responses to the modified proteins were examined using cells from malaria

We examined the hypothesis that recovery from uncomplicated malaria in patients carrying drug-resistant Plasmodium falciparum is a measure of acquired functional immunity and may therefore be associated with humoral responses to candidate vaccine antigens. Gambian children with malaria were treated with chloroquine in 28-day trials, and recovery was defined primarily as the absence of severe clinical malaria at any time and absence of parasitemia with fever after 3 days. Plasma samples from these children were assayed by enzyme-linked immunosorbent assay for immunoglobulin G (IgG) to recombinant merozoite antigens: apical membrane antigen 1 (AMA-1) and the 19-kDa C-terminal region of merozoite surface protein 1 (MSP-1(19)), including antigenic variants of MSP-1(19) with double and triple substitutions. Antigen-specific IgG was more frequent in children who recovered, particularly that for MSP-1(19) (age-adjusted odds ratios: 0.32 [95% confidence interval, 0.05, 1.87; P = 0.168] for AMA-1, 0.19 ...

We examined the hypothesis that recovery from uncomplicated malaria in patients carrying drug-resistant Plasmodium falciparum is a measure of acquired functional immunity and may therefore be associated with humoral responses to candidate vaccine antigens. Gambian children with malaria were treated with chloroquine in 28-day trials, and recovery was defined primarily as the absence of severe clinical malaria at any time and absence of parasitemia with fever after 3 days. Plasma samples from these children were assayed by enzyme-linked immunosorbent assay for immunoglobulin G (IgG) to recombinant merozoite antigens: apical membrane antigen 1 (AMA-1) and the 19-kDa C-terminal region of merozoite surface protein 1 (MSP-1(19)), including antigenic variants of MSP-1(19) with double and triple substitutions. Antigen-specific IgG was more frequent in children who recovered, particularly that for MSP-1(19) (age-adjusted odds ratios: 0.32 [95% confidence interval, 0.05, 1.87; P = 0.168] for AMA-1, 0.19 ...

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The role of submicroscopic infections in modulating malaria antibody responses is poorly understood and requires longitudinal studies. A cohort of 249 children ≤5 years of age, 126 children between 6 and 10 years and 134 adults ≥20 years was recruited in an area of intense malaria transmission in Apac, Uganda and treated with artemether/lumefantrine at enrolment. Parasite carriage was determined at enrolment and after 6 and 16 weeks using microscopy and PCR. Antibody prevalence and titres to circumsporozoite protein, apical membrane antigen-1 (AMA-1), merozoite surface protein-1 (MSP-119 ), merozoite surface protein-2 (MSP-2) and Anopheles gambiae salivary gland protein 6 (gSG6) were determined by ELISA. Plasmodium falciparum infections were detected in 38·1% (194/509) of the individuals by microscopy and in 57·1% (284/493) of the individuals by PCR at enrolment. Antibody prevalence and titre against AMA-1, MSP-119 , MSP-2 and gSG6 were related to concurrent (sub-)microscopic parasitaemia. ...

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Authors: Low, Andrew; Chandrashekaran, Indu; Adda, Christopher; Yao, Shenggan; Sabo, Jennifer; Zhang, Xuecheng; Soetopo, Alfreda; Anders, Robin; Norton, Raymond. Citation: Low, Andrew; Chandrashekaran, Indu; Adda, Christopher; Yao, Shenggan; Sabo, Jennifer; Zhang, Xuecheng; Soetopo, Alfreda; Anders, Robin; Norton, Raymond. Merozoite surface protein 2 of Plasmodium falciparum: expression, structure, dynamics, and fibril formation of the conserved N-terminal domain Biopolymers 87, 12-22 (2007).. Assembly members: ...

Background: The merozoite surface protein 7 (MSP7) is a Plasmodium protein which is involved in parasite invasion; the gene encoding it belongs to a multigene family. It has been proposed that MSP7 paralogues seem to be ...

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TY - JOUR. T1 - Molecular epidemiology of malaria in Cameroon. XVIII. Polymorphisms of the Plasmodium falciparum merozoite surface antigen-2 gene in isolates from symptomatic patients. AU - Basco, Leonardo K.. AU - Tahar, Rachida. AU - Escalante, Ananias. PY - 2004/3. Y1 - 2004/3. N2 - Merozoite surface antigen-2 (MSA-2) is a polymorphic genetic marker that is highly discriminatory for characterizing Plasmodium falciparum field isolates. Genetic diversity of isolates obtained from symptomatic patients residing in Yaounde, Cameroon was analyzed by an allele-specific polymerase chain reaction and direct sequencing of amplification products. Of 137 isolates, 25 (18%) had only FC27-type alleles, 40 (29%) had only 3D7-type alleles, and 72 (53%) had multiple parasite populations with both alleles. Of 295 fragments, 145 (49.2%) and 150 (50.8%) belonged to FC27 and 3D7 alleles, respectively. There were 23 different MSA-2 alleles (10 FC27-type and 13 3D7-type that yielded 44 different combinations in ...

Blood samples were collected from 12 residents of 4 villages in the Oksibil area of Irian Jaya. Eleven patients were positive for Plasmodium falciparum infection as evidenced by successful amplification of the MSA-2 gene by the polymerase chain reaction. Two patients showed evidence of infection by 2 strains of Plasmodium falciparum. All MSA-2 genes were completely sequenced and all could be assigned to one of the two major allelic families of MSA-2, however all MSA-2 gene sequences differed from previously described alleles. Five new allelic forms were identified, one of which was present in 8 of the 11 patients. Within small natural populations of P. falciparum, it appears that variation in MSA-2 approximates that seen world-wide. All samples were also analysed by hybridisation of amplified DNA to family specific probes and all samples hybridised to known probes. Our results demonstrate that there is a degree of microheterogeneity of MSA-2 that is undetectable by hybridisation studies alone ...

Plasmodium falciparum infection causes cerebral malaria (CM) in a subset of patients with anti-malarial treatment protecting only about 70% to 80% of patients. Why a subset of malaria patients develops CM complications, including neurological sequelae or death, is still not well understood. It is believed that host immune factors may modulate CM outcomes and there is substantial evidence that cellular immune factors, such as cytokines, play an important role in this process. In this study, the potential relationship between the antibody responses to the merozoite surface protein (MSP)-1 complex (which consists of four fragments namely: MSP-183, MSP-130, MSP-138 and MSP-142), MSP-636 and MSP-722 and CM was investigated. Peripheral blood antibody responses to recombinant antigens of the two major allelic forms of MSP-1 complex, MSP-636 and MSP-722 were compared between healthy subjects, mild malaria patients (MM) and CM patients residing in a malaria endemic region of central India. Total IgG and IgG

A chimeric proteins, PfMSP-Fu24, was constructed by genetically coupling immunodominant, conserved regions of two merozoite surface proteins, the 19-kDa region C-terminal region of merozoite surface protein 1 (PfMSP-119) and an 11-kDa conserved region of merozoite surface protein 3 (PfMSP-311), to augment the immunogenicity potential of these blood-stage malaria vaccine candidates. inhibitory antibody responses and inhibited growth of parasites in the presence as well as in the absence of human monocytes. These results suggest that PfMSP-Fu24 can form a constituent of a multistage malaria vaccine. INTRODUCTION is responsible for causing over 2 million deaths annually, and 90% of these deaths are reported to occur in children under the age of 5 years. An effective vaccine represents a high-priority intervention technique that could offer long-lasting safety from the condition (1,C5). Many malaria vaccines, like the liver-stage vaccine, RTS,S/ASO1, established that its feasible to interrupt the ...

Genotyping frequently is used to distinguish recrudescent from new infections in antimalarial drug efficacy trials, but methodology and interpretation of results have not been standardized. We compared the utility of polymorphisms within 3 Plasmodium falciparum genes during a longitudinal trial in Kampala, Uganda. Merozoite surface protein-1 (msp-1) and merozoite surface protein-2 (msp-2) revealed greater diversity than glutamate-rich protein. Genotypes based on msp-1, msp-2, and all 3 genes combined were compared for 394 initial and subsequent isolates. Classification of most episodes as due to recrudescence or reinfection was straightforward. In 24% (msp-1), 16% (msp-2), and 62% (3 genes combined) of samples, subsequent episodes contained identical and new alleles, however. Our analysis suggested that such episodes should be classified as reinfections and not recrudescence. Comparing the 3 studied genes, msp-2 results were most accurate, and analysis of this single gene effectively distinguished

1B9W: The crystal structure of C-terminal merozoite surface protein 1 at 1.8 A resolution, a highly protective malaria vaccine candidate.

In an area of intense transmission, a malaria vaccine could reduce infection due to the parasite types represented in the vaccine, but have no detectable effect on the overall frequency of infection if it did not protect against infection with heterologous parasites. These studies were performed to determine whether immunization with SPf66 decreased infection with homologous parasites containing the 11 amino acid peptide from merozoite surface protein-1 (MSP-1) in SPf66, or increased infection due to heterologous parasites containing heterologous (alternative) MSP-1 sequences. Based on this 11 amino acid peptide (YSLFQKEKMVL), three forward primers (S,Q,V) were designed to amplify the MSP-1 sequence present in SPf66, and 3 additional forward primers (G,H,I) to amplify the alternative MSP-1 sequence (YGLFHKEKMIL). This strategy was validated by polymerase chain reaction (PCR) amplification and dideoxy sequencing with 14 cloned laboratory isolates, which demonstrated that each primer amplified one MSP-1

MSP1 remains a candidate for inclusion in a malaria vaccine. Much attention has been focused on the C-terminal region of this molecule, particularly MSP119, the last approximately 100 amino acids preceding the GPI addition site [4]. This region is the target of antibodies that inhibit parasite growth by a variety of mechanisms [37]. The fine specificity of the antibody is crucial, and the binding sites of antibodies with different properties have been defined using a variety of techniques (reviewed in [4]). For example, amino acid substitutions in P. falciparum MSP119 have been used to map the binding of inhibitory, neutral and blocking antibodies [4,19]. Few studies have been carried out to determine the protective capacity of antibodies induced by immunization with such antigens [38-40]. Passive immunization with P. yoelii MSP119-mAbs can suppress a blood stage infection [10-11], and these antibodies react with some, but not all recombinant MSP119 of other P. yoelii lines, suggesting ...

Processing-inhibitory anti-MSP119 mAbs can prevent MSP-1 and erythrocyte invasion in in vitro culture, and can be rendered ineffective by the simultaneous

Prior to invasion, PfFormin1 and PfRON4 colocalize at the apical pole of free merozoites (Figure3A). However, in the rare event of capturing arrested invasion, fluorescence of both PfFormin1 and PfRON4 appear to split to form two distinct foci (a ring in three dimensions) either side of the merozoite at the interface with the erythrocyte (Figure3B). This is consistent with their location at the tight junction during merozoite invasion (Figure3; schematic). ...

PfMSP7 interacted with P-selectin at the surface of cells. a Schematic representing the experimental design, whereby recombinant, pentameric PfMSP7 proteins int

Plasmodium vivax merozoite surface protein-1 paralog (PvMSP1P) is a glycosylphosphatidylinositol-anchored protein expressed on the merozoite surface. This molecule is a target of natural immunity, as high anti-MSP1P-19 antibody levels were detected during P. vivax infection and the antibody inhibited PvMSP1P-erythrocyte binding. Recombinant PvMSP1P antigen results in production of a significant Th1 cytokine response in immunized mice. The present study was performed to characterize natural cellular immunity against PvMSP1P-19 and PvDBP region II in acute and recovery P. vivax infection. Peripheral blood mononuclear cells (PBMCs) from acute and recovery P. vivax infection were obtained for lymphocyte proliferation assay upon PvMSP1P-19 and PvDBP region II antigen stimulation. The culture supernatant was examined for the presence of the cytokines IL-2, TNF, IFN-γ and IL-10 by enzyme-linked immunosorbent assay (ELISA). To determine whether Th1 or Th2 have a memory response against PvMSP1P-19 and PvDBPII

Substantial evidence indicates that antibodies to Plasmodium falciparum merozoite antigens play a role in protection from malaria, although the precise targets and mechanisms mediating immunity remain unclear. Different malaria antigens induce distinct immunoglobulin G (IgG) subclass responses, but the importance of different responses in protective immunity from malaria is not known and the factors determining subclass responses in vivo are poorly understood. We examined IgG and IgG subclass responses to the merozoite antigens MSP1-19 (the 19-kDa C-terminal region of merozoite surface protein 1), MSP2 (merozoite surface protein 2), and AMA-1 (apical membrane antigen 1), including different polymorphic variants of these antigens, in a longitudinal cohort of children in Papua New Guinea. IgG1 and IgG3 were the predominant subclasses of antibodies to each antigen, and all antibody responses increased in association with age and exposure without evidence of increasing polarization toward one ...

The P. vivax parasite exhibits higher genetic diversity than P. falciparum, especially for the gene families associated with merozoite invasion or immune response modulation (e.g., the msp3, vir, and msp7 gene families) [20-22]. The high genetic diversity and natural selection of P. vivax vaccine targets is common existed in isolates world-wide [23,24]. The PvMSP1 locus codes for a major asexual blood-stage antigen currently proposed as a malaria vaccine candidate antigen. Reports of extensive polymorphism of this protein from field isolates and clones from different geographical areas remain a major challenge. Numerous studies on the genetic diversity of PvMSP1 in P. vivax field isolates have been carried out in many different geographic areas [25,26]. However, there is no available data for PvMSP142 from southern border areas adjacent to Myanmar and the inland cases in China.. In this study, we present several sets of genetic information for PvMSP142 of populations from inland China and CMB ...

Authors: Babon, Jeffrey; Morgan, William; Geoff, Kelly; John, Eccleston; James, Feeney; Anthony, Holder. Citation: Babon, Jeffrey; Morgan, William; Kelly, Geoff; Eccleston, John; Feeney, James; Holder, Anthony. Structural studies on Plasmodium vivax merozoite surface protein-1. Mol. Biochem. Parasitol. 153, 31-40 (2007).. Assembly members: ...

Although Plasmodium vivax is a leading cause of malaria around the world, only a handful of vivax antigens are being studied for vaccine development. Here, we investigated genetic signatures of selection and geospatial genetic diversity of two leading vivax vaccine antigens--Plasmodium vivax merozoite surface protein 1 (pvmsp-1) and Plasmodium vivax circumsporozoite protein (pvcsp). Using scalable next-generation sequencing, we deep-sequenced amplicons of the 42 kDa region of pvmsp-1 (n = 44) and the complete gene of pvcsp (n = 47) from Cambodian isolates. These sequences were then compared with global parasite populations obtained from GenBank. Using a combination of statistical and phylogenetic methods to assess for selection and population structure, we found strong evidence of balancing selection in the 42 kDa region of pvmsp-1, which varied significantly over the length of the gene, consistent with immune-mediated selection. In pvcsp, the highly variable central repeat region also showed patterns

To determine whether merozoites utilize distinct suites of genes to attach, invade, and replicate within feline enterocytes, we performed comparative transcriptional profiling on purified tachyzoites and merozoites. We used high-throughput RNA-Seq to compare the merozoite and tachyzoite transcriptomes. 8323 genes were annotated with sequence reads across the two asexually replicating stages of the parasite life cycle. Metabolism was similar between the two replicating stages. However, significant stage-specific expression differences were measured, with 312 transcripts exclusive to merozoites versus 453 exclusive to tachyzoites. Genes coding for 177 predicted secreted proteins and 64 membrane- associated proteins were annotated as merozoite-specific. The vast majority of known dense-granule (GRA), microneme (MIC), and rhoptry (ROP) genes were not expressed in merozoites. In contrast, a large set of surface proteins (SRS) was expressed exclusively in merozoites ...

Although a detailed picture of the initiation and regulation of daughter cell formation is emerging (Suvorova et al., 2015; Francia and Striepen, 2014), the coordination and assembly of the pellicle as the last step of budding is much less clear. In order to follow the PPM development through the erythrocytic cycle, we first generated a PPM marker that allows analysis of the PPM in living cells. PFF1210w is annotated as an integral 6-transmembrane domain protein and as a putative sphingomyelin-synthetase (SMS1, Fig. 4A). Overexpressed as an mCherry fusion protein, it localized at the periphery of the developing parasite (Fig. 4B; Fig. S3; Movie 3). It also highlights one or more cavities - specific PPM domains of yet unknown function (Grüring et al., 2011) - and colocalizes with the membrane marker fluorophore-labeled BODIPY©-FL C5-sphingomyelin lipid (Fig. 4D). Additionally, SMS1-mCherry plasma membrane association was verified through colocalization with the merozoite surface protein 1 ...

Buy anti-MSP2 antibody, Rabbit MSA2 PFB0300c Polyclonal Antibody-XP_001349578.1 (MBS1490049) product datasheet at MyBioSource, Primary Antibodies. Application: Western Blot (WB), ELISA (EIA). Not yet tested in other applications.

A 195,000 mol wt Plasmodium falciparum protein and processing fragments derived from it have been purified by monoclonal antibody affinity chromatography. A polyvalent antiserum has been raised against the purified protein and used to identify the terminal processing products associated with the merozoite. Three unique fragments of 83,000, 42,000, and 19,000 mol wt are present and they represent the major surface antigens of P. falciparum merozoites. ...

METHODS: The associations between antibody responses to the chimeric merozoite surface protein 1 block 2 hybrid (MSP1 hybrid), glutamate-rich protein region 2 (GLURP R2) and the peptide AS202.11, and the risk of malaria were assessed in children living in malaria hyperendemic (Burkina Faso, n = 354) and hypo-endemic (Ghana, n = 209) areas. Using the same reagent lots and standardized protocols for both study sites, immunoglobulin (Ig) M, IgG and IgG sub-class levels to each antigen were measured by ELISA in plasma from the children (aged 6-72 months). Associations between antibody levels and risk of malaria were assessed using Cox regression models adjusting for covariates ...

In areas where Plasmodium falciparum is endemic, immunoglobulin G is acquired by the fetus in utero, mainly during the third trimester of pregnancy. The potential protective effect of transferred anti-P. falciparum maternal antibodies was examined in a longitudinal study of 100 infants from birth to 1 year of age. The probability of acquiring a P. falciparum infection and developing an episode of clinical malaria was determined in relation to the P. falciparum-specific antibody level of the infant at birth against P. falciparum schizont antigen or recombinant merozoite surface protein MSP1(19) antigen. The risk of acquiring an episode of clinical malaria increased from birth to 6 months of age, after which it decreased. The overall prevalence of P. falciparum parasitemia was highest (48.9%) in the 6-month-old infants. The age-specific hematocrit value showed the lowest mean value (30.2) from 6 to 9 months, and the spleen rate was the highest (69.8%) at the same age. There was a lower risk of ...

Many microneme proteins are secreted onto the parasite surface to play a role in host cell entry and then ultimately shed. This study demonstrates that EBA-175, and, by extrapolation, all other DBL-EBPs, are subject to a similar fate. Given their role in invasion and their capacity to bind erythrocyte surface receptors with high affinity, these ligands presumably function in membrane bound form at the merozoite surface. Our results show that the truncated form of EBA-175 released into supernatants is a result of a physiologically important, precise cleavage event that takes place at the merozoite surface and is mediated via intramembrane cleavage by a rhomboid-like malarial protease.. IFA of newly invaded rings showed that, irrespective of whether EBA-175 was used as the dominant invasion ligand, invasion is associated with shedding of EBA-175. Western blot showed that the shed protein retains much or all of region VI, and mass spectrometric analysis allowed us to map its C terminus to an Ala ...

Fluorescent images of schizonts undergoing merogony (A-C), and four merozoites (D), labelled with antibodies to kinesin heavy chains (green) and a-tubulin (red), which labels the microtubules of f-MASTs, (merozoite assemblage of sub-pellicular mt) and DAPI nuclear stain (blue). A. Kinesin labelling is primarily associated with the residual body (r), but also radiates out in a series of linear arrays of discrete fluorescent points (Arrow) (i). Nuclei are shown by the DAPI staining (ii). B(i), kinesin labelling is seen at the periphery of the schizont, where the merozoite apices lie, and in the residual body (r), which is distinguished by the white glow of the pigment seen in the overlaid DIC image (ii). C(i), kinesin staining is apparent only at the periphery of the schizont where the merozoite apices are located, and is not apparent in the residual body area. D(i), the nuclei (n) are situated at the base of the merozoites, the f-MASTs (mt) run laterally, and the kinesin labelling (k) appears to ...

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BACKGROUND:Antibodies to the blood stages of malaria parasites enhance parasite clearance and antimalarial efficacy. The antibody subclass and functions that contribute to parasite clearance during antimalarial treatment and their relationship to malaria transmission intensity have not been characterized. METHODS:Levels of immunoglobulin G (IgG) subclasses and C1q fixation in response to Plasmodium falciparum merozoite antigens (erythrocyte-binding antigen [EBA] 175RIII-V, merozoite surface protein 2 [MSP-2], and MSP-142) and opsonic phagocytosis of merozoites were measured in a multinational trial assessing the efficacy of artesunate therapy across 11 Southeast Asian sites. Regression analyses assessed the effects of antibody seropositivity on the parasite clearance half-life (PC½), having a PC½ of ≥5 hours, and having parasitemia 3 days after treatment. RESULTS:IgG3, followed by IgG1, was the predominant IgG subclass detected (seroprevalence range, 5%-35% for IgG1 and 27%-41% for IgG3), varied

Babesia canis is an apicomplexan tick-transmitted hemoprotozoan responsible for causing canine babesiosis in Europe and west Asia. Despite its importance, there is no known rapid diagnostic kit detection of B. canis infection in dogs. The present study identified two novel antigens of B. canis and used the recombinant antigens to establish a rapid, specific and sensitive serodiagnostic technique for detection of B. canis infection. A complementary DNA (cDNA) expression library was constructed from the mRNA of B. canis and immunoscreened using B. canis-infected dog sera. The cDNAs encoding a merozoite surface antigen and a secreted antigen protein were identified and designated as BcMSA1 and BcSA1, respectively. The recombinant BcMSA1 and BcSA1 (rBcMSA1 and rBcSA1) expressed in Escherichia coli were purified and injected into mice for production of anti-sera. The native proteins were characterized by Western blot analysis and immunofluorescence. Furthermore, indirect enzyme

PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Sporozoites =, merozoites (in liver) =, merozoites (in RBCs) =, release of merozoites due to the RBC rupture, merozoites infect other RBCs. Some merozoites differentiate into gametocytes =, gametocytes containing red cells are sucked by female anopheles mosquito. ...

Most species in this family infect the Malpigian tubes of beetles. The trophozoite is conical in shape. Two types of schizogony occur in this family. In the first type the schizonts divide into merozoites with small nuclei. These are known as mycetoids merozoites. These develop into trophozoites. In the second form and more common form, the schizonts divide into merozoites with large nuclei: these are known as gregarinoid merozoites and give rise to gametocytes. The merozoites are uninucleated, pyriform cells. These are released into the lumen of the tube and from there infect other cells of the tube. The gametocytes possesses only a single nucleus and are globular in shape. When mature, these become detached from the epithelium. Within the lumen, the gametocytes associate in pairs, fuse and form a zygote. The zygote subsequently becomes a single octozoic spore. ...

Release of merozoite dense granules during erythrocyte invasion by Plasmodium knowlesi.: We used immunoelectron microscopy to study the fate of dense granules d

causes malaria disease through the asexual bloodstream levels of infections when merozoites invade replicate and erythrocytes. restricted junction between CB 300919 your invading erythrocyte and merozoite, the glycosylphosphatidylinositol (GPI)-anchored protein MSP2 and MSP4 are transported in to the erythrocyte without detectable digesting. Following invasion, MSP2 degrades within 10 min quickly, whereas MSP4 is certainly maintained all night. This shows that although some protein that are shed upon invasion may have assignments in preliminary get in touch with guidelines, others function during invasion and so are after that degraded, whereas others are internalized for assignments during intraerythrocytic advancement. Oddly enough, anti-MSP2 antibodies didnt inhibit invasion and rather were transported into erythrocytes and preserved for about 20 h without inhibiting parasite advancement. These findings offer brand-new insights in to the systems of invasion and understanding to advance the ...

De malariaparasiet binnenvalt en herhalingen binnen de rode bloedcellen. Nauwkeurige vaststelling van de merozoïet invasie en...

Discover Lifes page about the biology, natural history, ecology, identification and distribution of Potts-Santone, MarySusan I_MSP/0004 -- Discover Life

Discover Lifes page about the biology, natural history, ecology, identification and distribution of Potts-Santone, MarySusan I_MSP/0001 -- Discover Life

Link to Pubmed [PMID] - 25522250. PLoS Pathog. 2014 Dec;10(12):e1004520. All pathogenesis and death associated with Plasmodium falciparum malaria is due to parasite-infected erythrocytes. Invasion of erythrocytes by P. falciparum merozoites requires specific interactions between host receptors and parasite ligands that are localized in apical organelles called micronemes. Here, we identify cAMP as a key regulator that triggers the timely secretion of microneme proteins enabling receptor-engagement and invasion. We demonstrate that exposure of merozoites to a low K+ environment, typical of blood plasma, activates a bicarbonate-sensitive cytoplasmic adenylyl cyclase to raise cytosolic cAMP levels and activate protein kinase A, which regulates microneme secretion. We also show that cAMP regulates merozoite cytosolic Ca2+ levels via induction of an Epac pathway and demonstrate that increases in both cAMP and Ca2+ are essential to trigger microneme secretion. Our identification of the different ...

Differences in parasite transmission intensity influence the process of acquisition of host immunity to Plasmodium falciparum malaria and ultimately, the rate of malaria related morbidity and mortality. Potential vaccines being designed to complement current intervention efforts therefore need to be evaluated against different malaria endemicity backgrounds. The associations between antibody responses to the chimeric merozoite surface protein 1 block 2 hybrid (MSP1 hybrid), glutamate-rich protein region 2 (GLURP R2) and the peptide AS202.11, and the risk of malaria were assessed in children living in malaria hyperendemic (Burkina Faso, n = 354) and hypo-endemic (Ghana, n = 209) areas. Using the same reagent lots and standardized protocols for both study sites, immunoglobulin (Ig) M, IgG and IgG sub-class levels to each antigen were measured by ELISA in plasma from the children (aged 6-72 months). Associations between antibody levels and risk of malaria were assessed using Cox regressio

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The merozoites exit the liver cells and re-enter the bloodstream, beginning a cycle of invasion of red blood cells, asexual replication, and release of newly formed merozoites from the red blood cells repeatedly over 1-3 days*. This multiplication can result in thousands of parasite-infected cells in the host bloodstream, leading to illness and complications of malaria that can last for months if not treated ...