title: Immunisation with recombinant AMA-1 protects mice against infection with Plasmodium chabaudi.
abstract: The Plasmodium merozoite surface antigen apical membrane antigen-1 (AMA-1) has previously been shown to provide partial protection to Saimiri and rhesus monkeys immunised with recombinant Plasmodium fragile or parasite-derived Plasmodium knowlesi AMA-1, respectively. In the study reported here we have used the Plasmodium chabaudi/mouse model system to extend our pre-clinical assessment of an AMA-1 vaccine. We describe here the expression of the full-length Plasmodium chabaudi adami AMA-1 and the P. chabaudi adami AMA-1 ectodomain using both baculovirus and Escherichia coli. The ectodomain expressed in E. coli, which contained an N-terminal hexa-his tag, was purified by Ni-chelate chromatography and refolded in vitro in the presence of oxidised and reduced glutathione to generate intramolecular disulphide bonds. In a series of vaccine trials, in both inbred and outbred mice, highly significant protection was obtained by immunising with the refolded AMA-1 ectodomain. Protection was shown to correlate with antibody response and was dependent on intact disulphide bonds. Passive transfer of antibodies raised in rabbits against the refolded AMA-1 ectodomain was also protective. In view of this demonstration that E. coli expression of a soluble P. chabaudi AMA-1 domain can generate a vaccine that is effective in mice, we are pursuing a similar approach to generating a vaccine against P. falciparum for testing in human volunteers.
authors.affiliation: Cooperative Research Centre for Vaccine Technology, Post Office Royal Melbourne Hospital, Vic., Australia.
authors.forename: R F
authors.initials: RF
authors.lastname: Anders
authors.forename: P E
authors.initials: PE
authors.lastname: Crewther
authors.forename: S
authors.initials: S
authors.lastname: Edwards
authors.forename: M
authors.initials: M
authors.lastname: Margetts
authors.forename: M L
authors.initials: ML
authors.lastname: Matthew
authors.forename: B
authors.initials: B
authors.lastname: Pollock
authors.forename: D
authors.initials: D
authors.lastname: Pye
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology; D000953:Antigens, Protozoan; D008288:Malaria / Q000276:immunology / Q000517:prevention & control*; D017780:Malaria Vaccines / Q000008:administration & dosage*; D008565:Membrane Proteins / Q000008:administration & dosage* / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D016788:Plasmodium chabaudi / Q000276:immunology*; D015800:Protozoan Proteins / Q000008:administration & dosage* / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000008:administration & dosage
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D017780:Malaria Vaccines; D008565:Membrane Proteins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C090077:apical membrane antigen I, Plasmodium