scholarly journals Surface antigens of malaria merozoites. A high molecular weight precursor is processed to an 83,000 mol wt form expressed on the surface of Plasmodium falciparum merozoites.

1983 ◽  
Vol 158 (5) ◽  
pp. 1647-1653 ◽  
Author(s):  
R R Freeman ◽  
A A Holder
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Plasmodium Falciparum ◽  
Surface Antigens ◽  
Immune Serum ◽  
Differential Centrifugation ◽  
Synchronous Cultures ◽  
Human Immune ◽  
High Yields ◽  
Major Surface

A technique was developed for obtaining high yields of naturally released Plasmodium falciparum merozoites from synchronous cultures of parasitized erythrocytes. The cultured erythrocytes were treated with trypsin to prevent reinvasion (6), and the released merozoites that accumulated extracellularly were harvested by differential centrifugation. The total biosynthetically labeled proteins of schizonts and merozoites, and those immunoprecipitated by human immune serum were analyzed and compared. The surface antigens of free merozoites, labeled by lactoperoxidase-catalyzed iodination, were also described. A monoclonal antibody, specific for a 195,000 mol wt schizont protein, and processing fragments derived from it (3) were used in immunoprecipitation and Western transfer analyses to determine which of the processing fragments are associated with merozoites and which of them are located on the merozoite surface. It was found that processing of the 195,000 mol wt precursor down to an 83,000 mol wt fragment is complete in free merozoites, and that this fragment is expressed as one of the major surface antigens of P. falciparum merozoites.

scholarly journals The three major antigens on the surface of Plasmodium falciparum merozoites are derived from a single high molecular weight precursor.

1984 ◽  
Vol 160 (2) ◽  
pp. 624-629 ◽  
Author(s):  
A A Holder ◽  
R R Freeman
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Plasmodium Falciparum ◽  
Affinity Chromatography ◽  
High Molecular Weight ◽  
Surface Antigens ◽  
Antibody Affinity ◽  
Major Surface ◽  
Falciparum Protein

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.

scholarly journals Biosynthesis and processing of a Plasmodium falciparum schizont antigen recognized by immune serum and a monoclonal antibody.

1982 ◽  
Vol 156 (5) ◽  
pp. 1528-1538 ◽  
Author(s):  
A A Holder ◽  
R R Freeman
Keyword(s):  
Molecular Weight ◽  
Monoclonal Antibody ◽  
Plasmodium Falciparum ◽  
Malaria Parasite ◽  
Protective Antigen ◽  
Peptide Mapping ◽  
Immune Serum ◽  
Lower Molecular Weight ◽  
Developmental Cycle ◽  
Stage Of Development

Stage-specific protein synthesis by the erythrocytic forms of the malaria parasite Plasmodium falciparum was investigated by pulse labeling synchronous parasite cultures with [35S]methionine at 6-h intervals during a complete 48-h developmental cycle. About 40 labeled parasite proteins could be immunoprecipitated with human immune serum, and most of these were associated with the schizont stage of development. In particular, one schizont protein was a 195,000-mol wt species against which a murine monoclonal antibody was produced. This monoclonal antibody, 89.1 reacted with the parasite membrane in schizonts and also with the surface of free merozoites in the indirect immunofluorescence test. In addition to the 195,000-mol wt protein, antibody 89.1 immunoprecipitated a series of lower-molecular weight polypeptides from extracts of labeled asynchronous P. falciparum parasite cultures. These were shown to be related to the 195,000-mol wt protein by peptide mapping. Pulse-chase labeling of synchronized cultures, and immunoprecipitation with antibody 89.1, showed that specific processing of the 195,000-mol wt polypeptide to the lower-molecular-weight products in concomitant with schizont maturation and merozoite release. It is suggested that this P. falciparum protein may be analogous to a similarly processed 230,000-mol wt protective antigen of the rodent malaria parasite, P. yoelii.

scholarly journals Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 71-75
Author(s):  
EP Rock ◽  
EF Jr Roth ◽  
RR Rojas-Corona ◽  
JA Sherwood ◽  
RL Nagel ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cerebral Malaria ◽  
Ex Vivo ◽  
Rabbit Antiserum ◽  
Immune Serum ◽  
Red Cells ◽  
Specific Attachment ◽  
Infected Cells ◽  
Human Immune ◽  
Venular Endothelium

Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.

Primary structure of the precursor to the three major surface antigens of Plasmodium falciparum merozoites

Nature ◽  
1985 ◽  
Vol 317 (6034) ◽  
pp. 270-273 ◽  
Author(s):  
Anthony A. Holder ◽  
Michael J. Lockyer ◽  
Karel G. Odink ◽  
Jasbir S. Sandhu ◽  
Valentina Riveros-Moreno ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Primary Structure ◽  
Surface Antigens ◽  
Major Surface

scholarly journals An Opsonic Phagocytosis Assay for Plasmodium falciparum Sporozoites

2016 ◽  
Vol 24 (2) ◽  
Author(s):  
Ryan W. J. Steel ◽  
Brandon K. Sack ◽  
Moriya Tsuji ◽  
Mary Jane L. Navarro ◽  
Will Betz ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Immune System ◽  
Immune Serum ◽  
Phagocytic Cells ◽  
Protein Targets ◽  
Content Type ◽  
Flow Cytometric ◽  
Blood Stage Infection ◽  
Human Immune

ABSTRACT Plasmodium falciparum malaria remains the deadliest parasitic disease worldwide. Vaccines targeting the preerythrocytic sporozoite and liver stages have the potential to entirely prevent blood-stage infection and disease, as well as onward transmission. Sporozoite surface and secreted proteins are leading candidates for inclusion in a preerythrocytic stage-specific, antibody-based vaccine. Preclinical functional assays to identify humoral correlates of protection in vitro and to validate novel sporozoite protein targets for inclusion in multisubunit vaccines currently do not consider the interaction of sporozoite-targeting antibodies with other components of the immune system. Here, we describe the development of a simple flow cytometric assay to quantitatively assess the ability of antibodies directed against P. falciparum sporozoites to facilitate their phagocytosis. We demonstrate that this sporozoite opsonic phagocytosis assay (SOPA) is compatible with both monoclonal antibodies and human immune serum and can be performed using cryopreserved P. falciparum sporozoites. This simple, accessible assay will aid with the assessment of antibody responses to vaccination with Plasmodium antigens and their interaction with phagocytic cells of the immune system.

scholarly journals Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 71-75 ◽  
Author(s):  
EP Rock ◽  
EF Jr Roth ◽  
RR Rojas-Corona ◽  
JA Sherwood ◽  
RL Nagel ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cerebral Malaria ◽  
Ex Vivo ◽  
Rabbit Antiserum ◽  
Immune Serum ◽  
Red Cells ◽  
Specific Attachment ◽  
Infected Cells ◽  
Human Immune ◽  
Venular Endothelium

Abstract Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.

scholarly journals Polymorphism of the precursor for the major surface antigens of Plasmodium falciparum merozoites: studies at the genetic level.

1985 ◽  
Vol 4 (13B) ◽  
pp. 3823-3829 ◽  
Author(s):  
M. Mackay ◽  
M. Goman ◽  
N. Bone ◽  
J.E. Hyde ◽  
J. Scaife ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Antigens ◽  
Genetic Level ◽  
Major Surface

Induction of crisis forms in cultured Plasmodium falciparum with human immune serum from Sudan

Science ◽  
1982 ◽  
Vol 216 (4551) ◽  
pp. 1230-1233 ◽  
Author(s):  
J. Jensen ◽  
M. Boland ◽  
M Akood
Keyword(s):  
Plasmodium Falciparum ◽  
Immune Serum ◽  
Human Immune

scholarly journals Alteration in cytoadherence and rosetting of Plasmodium falciparum- infected thalassemic red blood cells

Blood ◽  
1993 ◽  
Vol 82 (12) ◽  
pp. 3752-3759 ◽  
Author(s):  
R Udomsangpetch ◽  
T Sueblinvong ◽  
K Pattanapanyasat ◽  
A Dharmkrong-at ◽  
A Kittikalayawong ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Plasmodium Falciparum ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Protective Role ◽  
Immune Serum ◽  
Schizont Stage ◽  
Ring Stage

Abstract Hemoglobinopathies have a protective role in malaria that appears to be related to alterations in red blood cell (RBC) properties. Thalassemic RBCs infected with Plasmodium falciparum showed greatly reduced cytoadherence and rosetting properties as well as impaired growth and multiplication. A significant decrease in the levels of falciparum antigens associated with the membrane of infected beta-thalassemic RBCs was observed at trophozoite/schizont stage, but not young ring stage. This reduction was shown when a cytoadherence inhibitory monoclonal antibody, but not a noninhibitory pooled immune serum, was used. These observations suggest that protection against malaria in thalassemia is caused by both reduced parasitemias and altered adherence properties of the infected thalassemic RBCs that promote enhanced clearance of the parasite from the circulation.

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