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 Biochemical and Immunological Characterization of Bacterially Expressed and Refolded Plasmodium falciparum 42-Kilodalton C-Terminal Merozoite Surface Protein 1

2003 ◽  
Vol 71 (12) ◽  
pp. 6766-6774 ◽  
Author(s):  
Sanjay Singh ◽  
Michael C. Kennedy ◽  
Carole A. Long ◽  
Allan J. Saul ◽  
Louis H. Miller ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Native Form ◽  
Immunological Characterization ◽  
E Coli ◽  
Merozoite Surface Protein 1 ◽  
Vaccine Trials

ABSTRACT Protection against Plasmodium falciparum can be induced by vaccination in animal models with merozoite surface protein 1 (MSP1), which makes this protein an attractive vaccine candidate for malaria. In an attempt to produce a product that is easily scaleable and inexpensive, we expressed the C-terminal 42 kDa of MSP1 (MSP142) in Escherichia coli, refolded the protein to its native form from insoluble inclusion bodies, and tested its ability to elicit antibodies with in vitro and in vivo activities. Biochemical, biophysical, and immunological characterization confirmed that refolded E. coli MSP142 was homogeneous and highly immunogenic. In a formulation suitable for human use, rabbit antibodies were raised against refolded E. coli MSP142 and tested in vitro in a P. falciparum growth invasion assay. The antibodies inhibited the growth of parasites expressing either homologous or heterologous forms of P. falciparum MSP142. However, the inhibitory activity was primarily a consequence of antibodies directed against the C- terminal 19 kDa of MSP1 (MSP119). Vaccination of nonhuman primates with E. coli MSP142 in Freund's adjuvant protected six of seven Aotus monkeys from virulent infection with P. falciparum. The protection correlated with antibody-dependent mechanisms. Thus, this new construct, E. coli MSP142, is a viable candidate for human vaccine trials.

scholarly journals In Vivo Expression and Immunological Studies of the 42-Kilodalton Carboxyl-Terminal Processing Fragment of Plasmodium falciparum Merozoite Surface Protein 1 in the Baculovirus-Silkworm System

2002 ◽  
Vol 70 (6) ◽  
pp. 2772-2779 ◽  
Author(s):  
Alan L. Y. Pang ◽  
Caryn N. Hashimoto ◽  
Leslie Q. Tam ◽  
Z. Q. Meng ◽  
George S. N. Hui ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
B Cell ◽  
Expression System ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Attractive Alternative ◽  
B Cell Epitopes ◽  
Merozoite Surface Protein 1 ◽  
Carboxyl Terminal

ABSTRACT The 42-kDa carboxyl-terminal processing fragment of Plasmodium falciparum merozoite surface protein 1 (MSP-142) is an anti-erythrocytic stage malaria vaccine candidate. In this study, MSP-142 was expressed by using the Bombyx mori nuclear polyhedrosis virus-silkworm expression system, and the antigenicity and immmunogenicity of the recombinant protein, Bmp42, were evaluated. The average yield of Bmp42, as determined by a sandwich enzyme-linked immunosorbent assay (ELISA), was 379 μg/ml of infected silkworm hemolymph, which was >100-fold higher than the level attainable in cell culture medium. N-terminal amino acid sequencing revealed that Bmp42 was correctly processed in silkworm cells. Data from immunoblotting, as well as from the inhibition ELISA, suggested that the conformational B-cell epitopes of MSP-142 were recreated in Bmp42. Immunization of rabbits with Bmp42 in complete Freund's adjuvant generated high-titer antibody responses against the immunogen. Specificity analyses of the anti-Bmp42 antibodies using several recombinant MSP-119 proteins expressing variant and conserved B-cell epitopes suggested that the anti-Bmp42 antibodies recognized primarily conserved epitopes on MSP-119. Furthermore, the anti-Bmp42 antibodies were highly effective in inhibiting the in vitro growth of parasites carrying homologous or heterologous MSP-142. Our results demonstrated that the baculovirus-silkworm expression system could be employed to express biologically and immunologically active recombinant MSP-142 at elevated levels; thus, it is an attractive alternative for producing a protective MSP-142 vaccine for human use.

scholarly journals Inhibitory Antibodies Specific for the 19-Kilodalton Fragment of Merozoite Surface Protein 1 Do Not Correlate with Delayed Appearance of Infection with Plasmodium falciparum in Semi-Immune Individuals in Vietnam

2009 ◽  
Vol 77 (10) ◽  
pp. 4510-4517 ◽  
Author(s):  
E. Elsa Herdiana Murhandarwati ◽  
Lina Wang ◽  
Casilda G. Black ◽  
Doan Hanh Nhan ◽  
Thomas L. Richie ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Plasmodium Yoelii ◽  
Enzyme Linked Immunosorbent Assay ◽  
Acquired Immunity ◽  
Homologous Region ◽  
Significant Component ◽  
Merozoite Surface Protein 1 ◽  
Inhibitory Antibodies

ABSTRACT Inhibitory antibodies specific for the 19-kDa fragment of merozoite surface protein 1 (MSP119) are a significant component of inhibitory responses in individuals immune to malaria. Nevertheless, conflicting results have been obtained in determining whether this antibody specificity correlates with protection in residents of areas where malaria is endemic. In this study, we examined sera collected from a population of semi-immune individuals living in an area of Vietnam with meso-endemicity during a 6-month period. We used two Plasmodium falciparum parasite lines that express either endogenous MSP119 or the homologous region from Plasmodium yoelii to measure the MSP119-specific inhibitory activity. We showed that (i) the level of MSP119-specific inhibitory antibodies was not associated with a delay in P. falciparum infection, (ii) MSP119-specific inhibitory antibodies declined significantly during the convalescent period after infection, and (iii) there was no significant correlation between the MSP119-specific inhibitory antibodies and the total antibodies measured by enzyme-linked immunosorbent assay. These results have implications for understanding naturally acquired immunity to malaria and for the development and evaluation of MSP119-based vaccines.

scholarly journals Levels of Antibody to Conserved Parts of Plasmodium falciparum Merozoite Surface Protein 1 in Ghanaian Children Are Not Associated with Protection from Clinical Malaria

1999 ◽  
Vol 67 (5) ◽  
pp. 2131-2137 ◽  
Author(s):  
Daniel Dodoo ◽  
Thor G. Theander ◽  
Jorgen A. L. Kurtzhals ◽  
Kojo Koram ◽  
Eleanor Riley ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Clinical Malaria ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Antibody ◽  
Merozoite Surface Protein 1 ◽  
Egf Domain ◽  
Antibody Specificities

ABSTRACT The 19-kDa conserved C-terminal part of the Plasmodium falciparum merozoite surface protein 1 (PfMSP119) is a malaria vaccine candidate antigen, and human antibody responses to PfMSP119 have been associated with protection against clinical malaria. In this longitudinal study carried out in an area of stable but seasonal malaria transmission with an estimated parasite inoculation of about 20 infective bites/year, we monitored 266 3- to 15-year-old Ghanaian children clinically and parasitologically over a period of 18 months. Blood samples were collected at the beginning of the study before the major malaria season in April and after the season in November. Using enzyme-linked immunosorbent assay, we measured antibody responses to recombinant gluthathioneS-transferase–PfMSP119 fusion proteins corresponding to the Wellcome and MAD20 allelic variants in these samples. Prevalence of antibodies recognizing the Wellcome 19 construct containing both epidermal growth factor (EGF)-like motifs in Wellcome type PfMSP119 was about 30%. Prevalence of antibodies to constructs containing only the first EGF domain from either Wellcome or MAD20 type PfMSP119 was about 15%, whereas antibodies recognizing a construct containing only the second EGF domain of MAD20 type PfMSP119 was found in only about 4% of the donors. Neither the prevalence nor the levels of any of the antibody specificities varied significantly with season, age, or sex. Significantly, and in contrast to previous reports from other parts of West Africa, we found no evidence of an association between antibody responses to PfMSP119and clinical protection against malaria.

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