Plasmodium falciparum: heterologous synthesis of the transmission-blocking vaccine candidate Pfs48/45 in recombinant vaccinia virus-infected cells.
With the aim of developing transmission-blocking vaccines based on the sexual stage-specific surface antigen Pfs48/45 of the human malaria parasite Plasmodium falciparum, the gene encoding Pfs48/45 was incorporated into the genome of a recombinant vaccinia virus. In virus-infected mammalian tissue culture cells, recombinant Pfs48/45 antigen (rPfs48/45) is posttranslational modified to produce a highly N-glycosylated polypeptide. The rPfs48/45 protein was radiolabeled with ethanolamine, consisting of a further posttranslational modification in the form of a glycosylphosphatidylinositol anchor at its carboxy-terminal end. The rPfs48/45 was not detected on the surface of the infected cells; instead, it remained within the secretion pathway of mammalian cells irrespective of the duration of infection or culture temperature. Studies with monoclonal antibodies specific for disulfide band-dependent epitopes of Pfs48/45 revealed that recombinant Pfs48/45 is not folded in its authentic conformation even if N-glycosylation was chemically inhibited. Infection of mice and rabbits with recombinant virus elicited Pfs48/45-specific antibodies; however, the antisera failed to block parasite transmission in a standard mosquito membrane-feeding assay.
Department of Molecular Biology, University of Nijmegen, Toernooiveld 1, Nijmegen, 6525 ED, The Netherlands.
R L
RL
Milek
A A
AA
DeVries
W F
WF
Roeffen
H
H
Stunnenberg
P J
PJ
Rottier
R N
RN
Konings
D000818:Animals; D000953:Antigens, Protozoan / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism; D000954:Antigens, Surface / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D019084:Fluorescent Antibody Technique, Indirect; D017780:Malaria Vaccines / Q000096:biosynthesis / Q000378:metabolism; D016778:Malaria, Falciparum / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D010963:Plasmodium falciparum / Q000276:immunology*; D011233:Precipitin Tests; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000096:biosynthesis* / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D014614:Vaccines, Synthetic / Q000096:biosynthesis / Q000378:metabolism; D014616:Vaccinia virus / Q000502:physiology
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D014614:Vaccines, Synthetic