scholarly journals Immunoglobulin G Antibody Reactivity to a Group A Plasmodium falciparum Erythrocyte Membrane Protein 1 and Protection from P. falciparum Malaria

2007 ◽  
Vol 75 (5) ◽  
pp. 2415-2420 ◽  
Author(s):  
Pamela A. Magistrado ◽  
John Lusingu ◽  
Lasse S. Vestergaard ◽  
Martha Lemnge ◽  
Thomas Lavstsen ◽  
...  

ABSTRACT Variant surface antigens (VSA) on the surface of Plasmodium falciparum-infected red blood cells play a major role in the pathogenesis of malaria and are key targets for acquired immunity. The best-characterized VSA belong to the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. In areas where P. falciparum is endemic, parasites causing severe malaria and malaria in young children with limited immunity tend to express semiconserved PfEMP1 molecules encoded by group A var genes. Here we investigated antibody responses of Tanzanians who were 0 to 19 years old to PF11_0008, a group A PfEMP1. PF11_0008 has previously been found to be highly transcribed in a nonimmune Dutch volunteer experimentally infected with NF54 parasites. A high proportion of the Tanzanian donors had antibodies against recombinant PF11_0008 domains, and in children who were 4 to 9 years old the presence of antibodies to the PF11_0008 CIDR2β domain was associated with reduced numbers of malaria episodes. These results indicate that homologues of PF11_0008 are present in P. falciparum field isolates and suggest that PF11_0008 CIDR2β-reactive antibodies might be involved in protection against malaria episodes.

Vaccine ◽  
2018 ◽  
Vol 36 (45) ◽  
pp. 6826-6833 ◽  
Author(s):  
Bernard N. Kanoi ◽  
Hikaru Nagaoka ◽  
Masayuki Morita ◽  
Michael T. White ◽  
Nirianne M.Q. Palacpac ◽  
...  

2013 ◽  
Vol 42 (4) ◽  
pp. 2270-2281 ◽  
Author(s):  
Adam F. Sander ◽  
Thomas Lavstsen ◽  
Thomas S. Rask ◽  
Michael Lisby ◽  
Ali Salanti ◽  
...  

Abstract Many bacterial, viral and parasitic pathogens undergo antigenic variation to counter host immune defense mechanisms. In Plasmodium falciparum, the most lethal of human malaria parasites, switching of var gene expression results in alternating expression of the adhesion proteins of the Plasmodium falciparum-erythrocyte membrane protein 1 class on the infected erythrocyte surface. Recombination clearly generates var diversity, but the nature and control of the genetic exchanges involved remain unclear. By experimental and bioinformatic identification of recombination events and genome-wide recombination hotspots in var genes, we show that during the parasite’s sexual stages, ectopic recombination between isogenous var paralogs occurs near low folding free energy DNA 50-mers and that these sequences are heavily concentrated at the boundaries of regions encoding individual Plasmodium falciparum-erythrocyte membrane protein 1 structural domains. The recombinogenic potential of these 50-mers is not parasite-specific because these sequences also induce recombination when transferred to the yeast Saccharomyces cerevisiae. Genetic cross data suggest that DNA secondary structures (DSS) act as inducers of recombination during DNA replication in P. falciparum sexual stages, and that these DSS-regulated genetic exchanges generate functional and diverse P. falciparum adhesion antigens. DSS-induced recombination may represent a common mechanism for optimizing the evolvability of virulence gene families in pathogens.


1998 ◽  
Vol 187 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Qijun Chen ◽  
Antonio Barragan ◽  
Victor Fernandez ◽  
Annika Sundström ◽  
Martha Schlichtherle ◽  
...  

Severe Plasmodium falciparum malaria is characterized by excessive sequestration of infected and uninfected erythrocytes in the microvasculature of the affected organ. Rosetting, the adhesion of P. falciparum–infected erythrocytes to uninfected erythrocytes is a virulent parasite phenotype associated with the occurrence of severe malaria. Here we report on the identification by single-cell reverse transcriptase PCR and cDNA cloning of the adhesive ligand P. falciparum erythrocyte membrane protein 1 (PfEMP1). Rosetting PfEMP1 contains clusters of glycosaminoglycan-binding motifs. A recombinant fusion protein (Duffy binding-like 1–glutathione S transferase; Duffy binding-like-1–GST) was found to adhere directly to normal erythrocytes, disrupt naturally formed rosettes, block rosette reformation, and bind to a heparin-Sepharose matrix. The adhesive interactions could be inhibited with heparan sulfate or enzymes that remove heparan sulfate from the cell surface whereas other enzymes or similar glycosaminoglycans of a like negative charge did not affect the binding. PfEMP1 is suggested to be the rosetting ligand and heparan sulfate, or a heparan sulfate–like molecule, the receptor both for PfEMP1 binding and naturally formed erythrocyte rosettes.


2003 ◽  
Vol 90 (6) ◽  
pp. 467-472 ◽  
Author(s):  
Raphael M. Oguariri ◽  
Denise Mattei ◽  
Cristina Tena-Tom�s ◽  
Anne-Catrin Uhlemann ◽  
Peter G. Kremsner ◽  
...  

2010 ◽  
Vol 6 (9) ◽  
pp. e1000933 ◽  
Author(s):  
Thomas S. Rask ◽  
Daniel A. Hansen ◽  
Thor G. Theander ◽  
Anders Gorm Pedersen ◽  
Thomas Lavstsen

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