Limited polymorphism in Plasmodium falciparum ookinete surface antigen, von Willebrand factor A domain-related protein from clinical isolates.
BACKGROUND
As malaria becomes increasingly drug resistant and more costly to treat, there is increasing urgency to develop effective vaccines. In comparison to other stages of the malaria lifecycle, sexual stage antigens are under less immune selection pressure and hence are likely to have limited antigenic diversity.


METHODS
Clinical isolates from a wide range of geographical regions were collected. Direct sequencing of PCR products was then used to determine the extent of polymorphisms for the novel Plasmodium falciparum sexual stage antigen von Willebrand Factor A domain-related Protein (PfWARP). These isolates were also used to confirm the extent of diversity of sexual stage antigen Pfs28.


RESULTS
PfWARP was shown to have non-synonymous substitutions at 3 positions and Pfs28 was confirmed to have a single non-synonymous substitution as previously described.


CONCLUSIONS
This study demonstrates the limited antigenic diversity of two prospective P. falciparum sexual stage antigens, PfWARP and Pfs28. This provides further encouragement for the proceeding with vaccine trials based on these antigens.
Richards
Jack S
JS
Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Grattan St, Parkville, Victoria, 3050, Australia. richards@wehi.edu.au
MacDonald
Nicholas J
NJ
Eisen
Damon P
DP
D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics*; D000954:Antigens, Surface / Q000235:genetics; D001483:Base Sequence; D016054:DNA, Protozoan / Q000032:analysis; D006801:Humans; D017780:Malaria Vaccines / Q000235:genetics; D016778:Malaria, Falciparum / Q000469:parasitology*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics*
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D016054:DNA, Protozoan; D017780:Malaria Vaccines; D015800:Protozoan Proteins; C121474:Pvs28 protein, P vivax; C434321:WARP protein, Plasmodium