The Neisseria meningitidis outer membrane protein P1 produced in Bacillus subtilis and reconstituted into phospholipid vesicles elicits antibodies to native P1 epitopes.
Class 1 outer membrane protein (P1) of Neisseria meningitidis group B is considered a promising vaccine candidate because P1 subtype-specific antibodies have been shown to be protective in an animal model. We have previously described the production of P1 in the Gram-positive Bacillus subtilis as intracellular inclusion bodies, from which the protein (BacP1) is easily purified (Nurminen et al., Mol. Microbiol., 1992, 2499-2506). We show here that the purified BacP1 can be reconstituted into phospholipid vesicles with the formation of the native immunodominant surface epitopes. The detergent-solubilized, completely denatured BacP1 was fused with phospholipid-detergent micelles during detergent removal by dialysis or gel filtration to yield protein-lipid vesicles (liposomes). When mice were immunized with these liposomes, they produced high titers of antibodies reacting in a P1 subtype-specific manner with meningococcal cells indicating the presence of conformation-dependent P1-specific epitopes in the liposomes. The results suggest that a vaccine candidate for meningococcal disease could be developed from the BacP1-liposomes. They furthermore demonstrate the feasibility of refolding a denatured outer membrane protein, which has never been exposed to lipopolysaccharide, into a native-like conformation.
Muttilainen
S
S
Department of Bacterial Vaccine Research and Molecular Bacteriology, National Public Health Institute, Helsinki, Finland.
Idänpään-Heikkilä
I
I
Wahlström
E
E
Nurminen
M
M
Mäkelä
P H
PH
Sarvas
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D001412:Bacillus subtilis; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D008081:Liposomes; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D008081:Liposomes; D011993:Recombinant Fusion Proteins