scholarly journals Naturally Acquired Antibody Responses to Plasmodium falciparum Merozoite Surface Protein 4 in a Population Living in an Area of Endemicity in Vietnam

2001 ◽  
Vol 69 (7) ◽  
pp. 4390-4397 ◽  
Author(s):  
Lina Wang ◽  
Thomas L. Richie ◽  
Anthony Stowers ◽  
Doan Hanh Nhan ◽  
Ross L. Coppel
Keyword(s):  
Plasmodium Falciparum ◽  
Disulfide Bonds ◽  
Surface Protein ◽  
Integral Membrane Protein ◽  
Merozoite Surface Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Surveillance Period ◽  
Human Antibodies ◽  
Study Population ◽  
A Subunit

ABSTRACT Merozoite surface protein 4 (MSP4) of Plasmodium falciparum is a glycosylphosphatidylinositol-anchored integral membrane protein that is being developed as a component of a subunit vaccine against malaria. We report here the measurement of naturally acquired antibodies to MSP4 in a population of individuals living in the Khanh-Hoa region of Vietnam, an area where malaria is highly endemic. Antibodies to MSP4 were detected in 94% of the study population at titers of 1:5,000 or greater. Two forms of recombinant MSP4 produced in either Escherichia coli orSaccharomyces cerevisiae were compared as substrates in the enzyme-linked immunosorbent assay. There was an excellent correlation between reactivity measured to either, although the yeast substrate was recognized by a higher percentage of sera. Four different regions of MSP4 were recognized by human antibodies, demonstrating that there are at least four distinct epitopes in this protein. In the carboxyl terminus, where the single epidermal growth factor-like domain is located, the reactive epitope(s) was shown to be conformation dependent, as disruption of the disulfide bonds almost completely abolished reactivity with human antibodies. The anti-MSP4 antibodies were mainly of the immunoglobulin G1 (IgG1) and IgG3 subclasses, suggesting that such antibodies may play a role in opsonization and complement-mediated lysis of free merozoites. Individuals in the study population were drug-cured and followed up for 6 months; no significant correlation was observed between the anti-MSP4 antibodies and the absence of parasitemia during the surveillance period. As a comparison, antibodies to MSP119, a leading vaccine candidate, were measured, and no correlation with protection was observed in these individuals. The anti-MSP119 antibodies were predominantly of the IgG1 isotype, in contrast to the IgG3 predominance noted for MSP4.

scholarly journals Fine Specificity of Serum Antibodies to Plasmodium falciparum Merozoite Surface Protein, PfMSP-119, Predicts Protection from Malaria Infection and High-Density Parasitemia

2004 ◽  
Vol 72 (3) ◽  
pp. 1557-1567 ◽  
Author(s):  
Brenda A. Okech ◽  
Patrick H. Corran ◽  
James Todd ◽  
Amy Joynson-Hicks ◽  
Chairat Uthaipibull ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Field Studies ◽  
Merozoite Surface Protein ◽  
High Density ◽  
Enzyme Linked Immunosorbent Assay ◽  
Fine Specificity ◽  
Vaccine Trials ◽  
C Terminus ◽  
Falciparum Merozoite

ABSTRACT Antibodies to the C terminus of the Plasmodium falciparum merozoite surface protein, PfMSP-119, may inhibit merozoite invasion or block the effects of inhibitory antibodies. Here, using a competition enzyme-linked immunosorbent assay and antibody binding to wild-type and mutated recombinant proteins, we show that there are marked variations between individuals in the fine specificity of naturally acquired anti-MSP-119 antibodies. Furthermore, although neither the prevalence nor the concentration of total anti-MSP-119 antibodies was associated with resistance to malaria in African children, significant associations were observed between antibody fine specificity and subsequent risk of infection and high-density parasitemia during a follow-up period. Thus, the fine specificity of naturally acquired human anti-MSP-119 antibodies is crucial in determining their function. Future field studies, including the evaluation of PfMSP-1 vaccine trials, should include assays that explore antibody fine specificity as well as titer.

scholarly journals Levels of Plasma Immunoglobulin G with Specificity against the Cysteine-Rich Interdomain Regions of a Semiconserved Plasmodium falciparum Erythrocyte Membrane Protein 1, VAR4, Predict Protection against Malarial Anemia and Febrile Episodes

2006 ◽  
Vol 74 (5) ◽  
pp. 2867-2875 ◽  
Author(s):  
John P. A. Lusingu ◽  
Anja T. R. Jensen ◽  
Lasse S. Vestergaard ◽  
Daniel T. Minja ◽  
Michael B. Dalgaard ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Immunoglobulin G ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Erythrocyte Membrane Protein ◽  
Igg Binding ◽  
Febrile Episodes

ABSTRACT Antibodies to variant surface antigen have been implicated as mediators of malaria immunity in studies measuring immunoglobulin G (IgG) binding to infected erythrocytes. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is an important target for these antibodies, but no study has directly linked the presence of PfEMP1 antibodies in children to protection. We measured plasma IgG levels to the cysteine-rich interdomain region 1α (CIDR1α) of VAR4 (VAR4-CIDR1α), a member of a semiconserved PfEMP1 subfamily, by enzyme-linked immunosorbent assay in 561 Tanzanian individuals, who were monitored clinically for 7 months. The participants resided in Mkokola (a high-transmission village where malaria is holoendemic) or Kwamasimba (a moderate-transmission village). For comparison, plasma IgG levels to two merozoite surface protein 1 (MSP1) constructs, MSP1-19 and MSP1 block 2, and a control CIDR1 domain were measured. VAR4-CIDR1α antibodies were acquired at an earlier age in Mkokola than in Kwamasimba, but after the age of 10 years the levels were comparable in the two villages. After controlling for age and other covariates, the risk of having anemia at enrollment was reduced in VAR4-CIDR1α responders for Mkokola (adjusted odds ratio [AOR], 0.49; 95% confidence interval [CI], 0.29 to 0.88; P = 0.016) and Kwamasimba (AOR, 0.33; 95% CI, 0.16 to 0.68; P = 0.003) villages. The risk of developing malaria fever was reduced among individuals with a measurable VAR4-CIDR1α response from Mkokola village (AOR, 0.51; 95% CI, 0.29 to 0.89; P = 0.018) but not in Kwamasimba. Antibody levels to the MSP1 constructs and the control CIDR1α domain were not associated with morbidity protection. These data strengthen the concept of developing vaccines based on PfEMP1.

scholarly journals Immunization with Recombinant Plasmodium yoelii Merozoite Surface Protein 4/5 Protects Mice against Lethal Challenge

2000 ◽  
Vol 68 (10) ◽  
pp. 6034-6037 ◽  
Author(s):  
Lukasz Kedzierski ◽  
Casilda G. Black ◽  
Ross L. Coppel
Keyword(s):  
Plasmodium Falciparum ◽  
Recombinant Protein ◽  
Subunit Vaccine ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Plasmodium Yoelii ◽  
Lethal Challenge ◽  
A Subunit ◽  
Peak Parasitemia ◽  
Antibody Levels

ABSTRACT Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5), expressed as a recombinant protein, was highly effective at protecting mice against lethal challenge with P. yoelii. There was a significant correlation between prechallenge antibody levels and peak parasitemia, suggesting that the homologues of PyMSP4/5 in Plasmodium falciparum are promising components of a subunit vaccine against malaria.

scholarly journals Multiplex Assay for Simultaneous Measurement of Antibodies to Multiple Plasmodium falciparum Antigens

2006 ◽  
Vol 13 (12) ◽  
pp. 1307-1313 ◽  
Author(s):  
Genevieve G. Fouda ◽  
Rose F. G. Leke ◽  
Carole Long ◽  
Pierre Druilhe ◽  
Ainong Zhou ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Multiplex Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Suspension Array ◽  
Large Numbers ◽  
Erythrocyte Surface ◽  
Large Populations ◽  
Erythrocyte Binding

ABSTRACTAntibodies toPlasmodium falciparumare classically measured using the enzyme-linked immunosorbent assay (ELISA). Although highly sensitive, this technique is labor-intensive when large numbers of samples must be screened against multiple antigens. The suspension array technology (SAT) might be an alterative to ELISA, as it allows measurement of antibodies against multiple antigens simultaneously with a small volume of sample. This study sought to adapt the new SAT multiplex system for measuring antibodies against nine malarial vaccine candidate antigens, including recombinant proteins from two variants of merozoite surface protein 1, two variants of apical merozoite antigen 1, erythrocyte binding antigen 175, merozoite surface protein 3, and peptides from the circumsporozoite protein, ring erythrocyte surface antigen, and liver-stage antigen 1. Various concentrations of the antigens were coupled to microspheres with different spectral addresses, and plasma samples from Cameroonian adults were screened by SAT in mono- and multiplex formats and by ELISA. Optimal amounts of protein required to perform the SAT assay were 10- to 100-fold less than that needed for ELISA. Excellent agreement was found between the single and multiplex formats (R≥ 0.96), even when two variants of the same antigen were used. The multiplex assay was rapid, reproducible, required less than 1 μl of plasma, and had a good correlation with ELISA. Thus, SAT provides an important new tool for studying the immune response to malaria rapidly and efficiently in large populations, even when the amount of plasma available is limited, e.g., in studies of neonates or finger-prick blood.

scholarly journals Structural and Antigenic Properties of Merozoite Surface Protein 4 of Plasmodium falciparum

1999 ◽  
Vol 67 (5) ◽  
pp. 2193-2200 ◽  
Author(s):  
Lina Wang ◽  
Casilda G. Black ◽  
Vikki M. Marshall ◽  
Ross L. Coppel
Keyword(s):  
Plasmodium Falciparum ◽  
Immune Responses ◽  
Recombinant Proteins ◽  
Surface Protein ◽  
Integral Membrane Protein ◽  
Merozoite Surface Protein ◽  
Antigenic Properties ◽  
Epidermal Growth ◽  
Human Immune ◽  
Antibody Preparations

ABSTRACT Merozoite surface protein 4 (MSP4) of Plasmodium falciparum is a glycosylphosphatidylinositol-anchored integral membrane protein of 272 residues that possesses a single epidermal growth factor (EGF)-like domain near the carboxyl terminus. We have expressed both full-length MSP4 and a number of fragments inEscherichia coli and have used these recombinant proteins to raise experimental antisera. All recombinant proteins elicited specific antibodies that reacted with parasite-derived MSP4 by immunoblotting. Antibody reactivity was highly dependent on the protein conformation. For example, reduction and alkylation of MSP4 almost completely abolished the reactivity of several antibody preparations, including specificities directed to regions of the protein that do not contain cysteine residues and are far removed from the cysteine-containing EGF-like domain. This indicated the presence of conformation-dependent epitopes in MSP4 and demonstrated that proper folding of the EGF-like domain influenced the antigenicity of the entire molecule. The recombinant proteins were used to map epitopes recognized by individuals living in areas where malaria is endemic, and at least four distinct regions are naturally antigenic during infection. Binding of human antibodies to the EGF-like domain was essentially abrogated after reduction of the recombinant protein, indicating the recognition of conformational epitopes by the human immune responses. This observation led us to examine the importance of conformation dependence in responses to other integral membrane proteins of asexual stages. We analyzed the natural immune responses to a subset of these antigens and demonstrated that there is diminished reactivity to several antigens after reduction. These studies demonstrate the importance of reduction-sensitive structures in the maintenance of the antigenicity of several asexual-stage antigens and in particular the importance of the EGF-like domain in the antigenicity of MSP4.

scholarly journals The Clinical-Grade 42-Kilodalton Fragment of Merozoite Surface Protein 1 of Plasmodium falciparum Strain FVO Expressed in Escherichia coli Protects Aotus nancymai against Challenge with Homologous Erythrocytic-Stage Parasites

2005 ◽  
Vol 73 (1) ◽  
pp. 287-297 ◽  
Author(s):  
Christian A. Darko ◽  
Evelina Angov ◽  
William E. Collins ◽  
Elke S. Bergmann-Leitner ◽  
Autumn S. Girouard ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Clinical Grade ◽  
Erythrocytic Stage ◽  
Malaria Parasites ◽  
E Coli ◽  
Merozoite Surface Protein 1

ABSTRACT A 42-kDa fragment from the C terminus of major merozoite surface protein 1 (MSP1) is among the leading malaria vaccine candidates that target infection by asexual erythrocytic-stage malaria parasites. The MSP142 gene fragment from the Vietnam-Oak Knoll (FVO) strain of Plasmodium falciparum was expressed as a soluble protein in Escherichia coli and purified according to good manufacturing practices. This clinical-grade recombinant protein retained some important elements of correct structure, as it was reactive with several functional, conformation-dependent monoclonal antibodies raised against P. falciparum malaria parasites, it induced antibodies (Abs) that were reactive to parasites in immunofluorescent Ab tests, and it induced strong growth and invasion inhibitory antisera in New Zealand White rabbits. The antigen quality was further evaluated by vaccinating Aotus nancymai monkeys and challenging them with homologous P. falciparum FVO erythrocytic-stage malaria parasites. The trial included two control groups, one vaccinated with the sexual-stage-specific antigen of Plasmodium vivax, Pvs25, as a negative control, and the other vaccinated with baculovirus-expressed MSP142 (FVO) as a positive control. Enzyme-linked immunosorbent assay (ELISA) Ab titers induced by E. coli MSP142 were significantly higher than those induced by the baculovirus-expressed antigen. None of the six monkeys that were vaccinated with the E. coli MSP142 antigen required treatment for uncontrolled parasitemia, but two required treatment for anemia. Protective immunity in these monkeys correlated with the ELISA Ab titer against the p19 fragment and the epidermal growth factor (EGF)-like domain 2 fragment of MSP142, but not the MSP142 protein itself or the EGF-like domain 1 fragment. Soluble MSP142 (FVO) expressed in E. coli offers excellent promise as a component of a vaccine against erythrocytic-stage falciparum malaria.

scholarly journals Genetic diversity and complexity of Plasmodium falciparum infections in the microenvironment among siblings of the same household in North-Central Nigeria

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Segun Isaac Oyedeji ◽  
Peter Usman Bassi ◽  
Samuel Adeola Oyedeji ◽  
Olusola Ojurongbe ◽  
Henrietta Oluwatoyin Awobode
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Clinical Malaria ◽  
Genetic Characteristics ◽  
North Central ◽  
Allele Type ◽  
Allele Specific ◽  
Study Population

Abstract Background Plasmodium falciparum parasites are known to exhibit extensive genetic diversity in areas of high transmission intensity and infected individuals in such communities often harbour several complex mixtures of parasite clones with different genetic characteristics. However, in the micro-environment, the extent of genetic diversity of P. falciparum parasites remain largely unknown. In this study therefore, the complexity of P. falciparum infections in households was investigated among symptomatic siblings, living under the same roof in north-central Nigeria. Methods Children were enrolled into the study if they were at least two from a household and presented with symptoms of uncomplicated malaria. Clinical malaria was confirmed by light microscopy of Giemsa-stained thick and thin blood films. Genomic DNA was isolated from blood spots on filter paper. Molecular characterization of P. falciparum isolates was done by allele-specific nested PCR of the highly polymorphic merozoite surface protein-2 (msp-2) gene. Results Ninety-three children from 43 households were enrolled into this study. A total of 26 different msp-2 alleles were identified from 215 fragments (range: 180–480 bp). Majority of the isolates [65.6% (n = 61)] were polyclonal infections consisting of 2–6 clones and were significantly more common with the FC27 allelic family (p = 0.036). The multiplicity of infection (MOI) per household ranged from 1.0 to 4.5 while the overall MOI in the study population was 2.31. The pattern of distribution of msp-2 allele types among the households fell into two categories: households where both msp-2 allele types (FC27 and 3D7) were present; households where only one msp-2 allele type (FC27 or 3D7) was present. Majority of the households [88.4% (n = 38)], had both msp-2 allele types but they were disproportionately distributed among the children while in a few households [11.6% (n = 5)], all the children were infected with only one type of msp-2 allele. Conclusion These findings showed that P. falciparum isolates exhibit remarkable degree of genetic diversity in the micro-environment and are composed mainly of multiclonal infections, which is an indication of a high ongoing parasite transmission. This suggests that the micro-environment is an important area of focus for malaria control interventions and for evaluating intervention programmes.

Sign in / Sign up

Export Citation Format

Share Document