title: Comparison of immunogenicity of five MSP1-based malaria vaccine candidate antigens in rabbits.
abstract: A number of laboratories around the world are producing Plasmodium falciparum erythrocyte-stage vaccine candidates in the pursuit of a vaccine against clinical malaria disease. These candidates are often based on the same parasite protein. Rigorous clinical development and testing of multiple candidates is limited by available resources, which underscores the need to conduct comparative studies of the different vaccine candidates. The purpose of this study was to compare five different candidate proteins all based on P. falciparum merozoite surface protein-1 (MSP1). After investigators submitted their candidates, basic protein profiles were evaluated in a blinded fashion by an independent laboratory, and groups of rabbits were immunized with the proteins. Sera obtained from the rabbits were compared for antibody titers by ELISA and for functional activity by an in vitro parasite growth inhibition assay (GIA) activity, again in a blinded fashion. In selected cases the fine specificity of the antibodies was assessed. Significant differences in immunogenicity as well as the functional activity of antibodies induced by the various vaccine candidates were noted. Data from this study can assist in making decisions for further clinical development of MSP1-based candidates, and this process sets a precedent for future comparisons of malaria vaccine candidates.
authors.affiliation: Initiative for Vaccines Research, World Health Organization, Geneva, Switzerland. reedz@who.int
authors.forename: Zarifah Hussain
authors.initials: ZH
authors.lastname: Reed
authors.forename: Marie Paule
authors.initials: MP
authors.lastname: Kieny
authors.forename: Howard
authors.initials: H
authors.lastname: Engers
authors.forename: Martin
authors.initials: M
authors.lastname: Friede
authors.forename: Sandra
authors.initials: S
authors.lastname: Chang
authors.forename: Shirley
authors.initials: S
authors.lastname: Longacre
authors.forename: Pawan
authors.initials: P
authors.lastname: Malhotra
authors.forename: Weiqing
authors.initials: W
authors.lastname: Pan
authors.forename: Carole
authors.initials: C
authors.lastname: Long
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D000913:Antibodies, Protozoan / Q000097:blood; D000918:Antibody Specificity; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D017780:Malaria Vaccines / Q000235:genetics / Q000276:immunology*; D016778:Malaria, Falciparum / Q000276:immunology / Q000517:prevention & control; D020066:Merozoite Surface Protein 1 / Q000235:genetics / Q000276:immunology*; D010963:Plasmodium falciparum / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D011817:Rabbits; D022223:Vaccines, Subunit / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D017780:Malaria Vaccines; D020066:Merozoite Surface Protein 1; D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic