title: Effect of Plasmodium yoelii exposure on vaccination with the 19-kilodalton carboxyl terminus of merozoite surface protein 1 and vice versa and implications for the application of a human malaria vaccine.
abstract: It is well known that exposure to one antigen can modulate the immune responses that develop following exposure to closely related antigens. It is also known that the composition of the repertoire can be skewed to favor epitopes shared between a current infection and a preceding one, a phenomenon referred to as "original antigenic sin." It was of interest, therefore, to investigate the antibody response that develops following exposure to the malaria vaccine candidate homologue Plasmodium yoelii MSP1(19) in mice that had previously experienced malaria infection and vice versa. In this study, preexposure of mice to Plasmodium yoelii elicited native anti-MSP1(19) antibody responses, which could be boosted by vaccination with recombinant MSP1(19). Likewise, infection of MSP1(19)-primed mice with P. yoelii led to an increase of anti-MSP1(19) antibodies. However, this increase was at the expense of antibodies to parasite determinants other than MSP1(19). This change in the balance of antibody specificities significantly affected the ability of mice to withstand a subsequent infection. These data have particular relevance to the possible outcome of malaria vaccination for those situations where the vaccine response is suboptimal and suggest that suboptimal vaccination may in fact render the ultimate acquisition of natural immunity more difficult.
authors.affiliation: Queensland Institute of Medical Research, P.O. Royal Brisbane Hospital, Brisbane, Queensland 4029, Australia.
authors.forename: Jiraprapa
authors.initials: J
authors.lastname: Wipasa
authors.forename: Huji
authors.initials: H
authors.lastname: Xu
authors.forename: Xueqin
authors.initials: X
authors.lastname: Liu
authors.forename: Chakrit
authors.initials: C
authors.lastname: Hirunpetcharat
authors.forename: Anthony
authors.initials: A
authors.lastname: Stowers
authors.forename: Michael F
authors.initials: MF
authors.lastname: Good
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D005260:Female; D006801:Humans; D008288:Malaria / Q000517:prevention & control*; D017780:Malaria Vaccines / Q000008:administration & dosage / Q000276:immunology*; D020066:Merozoite Surface Protein 1 / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010967:Plasmodium yoelii / Q000276:immunology*; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D017780:Malaria Vaccines; D020066:Merozoite Surface Protein 1; D022223:Vaccines, Subunit