The Neisseria meningitidis outer membrane protein P1 produced in Bacillus subtilis and reconstituted into phospholipid vesicles elicits antibodies to native P1 epitopes

• Published in: Microbial pathogenesis 1995-06, Vol.18 (6), p.423-436
• Main Authors: Muttilainen, S, Idänpään-Heikkilä, I, Wahlström, E, Nurminen, M, Mäkelä, P H, Sarvas, M
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibodies, Bacterial - immunology; Antigens, Bacterial - immunology; Bacillus subtilis; Bacterial Outer Membrane Proteins - biosynthesis; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - immunology; Epitopes - immunology; Liposomes; Molecular Sequence Data; Neisseria meningitidis; Neisseria meningitidis - immunology; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - immunology
• ISSN: 0882-4010
• DOI: 10.1006/mpat.1995.0038

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.