title: Structural conformers produced during malaria vaccine production in yeast.
abstract: A recombinant protein expression system based on Saccharomyces cerevisiae has been used to express malarial vaccine candidate antigens. The antigens so produced have been used in three Phase 1 clinical trials and numerous preclinical non-human primate trials. Further Phase I trials are planned using these candidate vaccine antigens. These molecules were identified as attractive candidates for antimalarial vaccines, as they are all surface-exposed at some stage in the parasite's life cycle. They all share an unusual structural feature: epidermal growth factor (EGF)-like motifs. When these proteins are expressed in our S. cerevisiae expression system, they are produced as a series of stable structural conformers, each with a different disulphide bonding pattern. This leads to both biochemical and, more importantly, antigenic differences between the conformers (e.g. presence or absence of an antibody B cell epitope). These findings have important ramifications for other EGF-domain-containing proteins expressed in S. cerevisiae, or for proteins which contain other cysteine-folding motifs not normally expressed by this organism, both for vaccine production or for research/reagent purposes.
authors.affiliation: Malaria Vaccine Development Unit, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA. AStowers@niaid.nih.gov
authors.forename: A W
authors.initials: AW
authors.lastname: Stowers
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: R L
authors.initials: RL
authors.lastname: Shimp
authors.forename: D C
authors.initials: DC
authors.lastname: Kaslow
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D017321:Clinical Trials, Phase I as Topic; D004220:Disulfides / Q000737:chemistry; D004815:Epidermal Growth Factor / Q000737:chemistry; D006801:Humans; D017780:Malaria Vaccines / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D010963:Plasmodium falciparum / Q000276:immunology; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae; D014614:Vaccines, Synthetic / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000953:Antigens, Protozoan; D004220:Disulfides; D017780:Malaria Vaccines; D014614:Vaccines, Synthetic; D004815:Epidermal Growth Factor