title: Characterization of a human reference standard for antibody to Plasmodium falciparum merozoite surface protein 1(42).
abstract: Volunteers vaccinated with a candidate malaria vaccine containing merozoite surface protein 1(42) (MSP-1(42)) exhibit antibodies to MSP-1(42) that are measured by enzyme-linked immunosorbent assay (ELISA). The purpose of this study was to make a human reference standard for MSP-1(42) antibody measured in absolute quantity units using pooled plasma samples known to contain high titers of MSP-1(42) antibody based on previous ELISA results. Immobilized metal affinity chromatography was used to determine the amount of MSP-1(42) antibody in this plasma pool. Hexahistidine-tagged MSP-1(42) antigen adsorbed to nickel-chelating resin was used to capture MSP-1(42) antibody from the plasma pool. The intact MSP-1(42) antibody-antigen complexes were eluted and total IgG was measured by an ELISA standardized against purified human IgG. In this way, the human reference standard was determined to contain 48.3 microg/mL of MSP-1(42) antibody. This reference standard may be useful as a quantitative working standard for measuring MSP-1(42) antibody response in future vaccine clinical trials involving MSP-1.
authors.affiliation: Division of Communicable Diseases and Immunology, Department of Immunology, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, USA. in-kyu.yoon@na.amedd.army.mil
authors.forename: In-Kyu
authors.initials: IK
authors.lastname: Yoon
authors.forename: Evelina
authors.initials: E
authors.lastname: Angov
authors.forename: David
authors.initials: D
authors.lastname: Larson
authors.forename: D Gray
authors.initials: DG
authors.lastname: Heppner
authors.forename: James F
authors.initials: JF
authors.lastname: Cummings
authors.forename: V Ann
authors.initials: VA
authors.lastname: Stewart
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D010963:Plasmodium falciparum / Q000276:immunology*; D012015:Reference Standards; D013381:Subtilisins / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D013381:Subtilisins; C119550:sub-2 protein, Plasmodium falciparum