Immunogenicity of peptides derived from a fibronectin-binding protein of S-aureus expressed on two different plant viruses

The D2 peptide derived from an S. aureus fibronectin-binding protein (FnBP) was expressed on the surface of the icosahedral cowpea mosaic virus (amino acids 1-30 of D2) or on the rod-shaped potato virus X (amino acids 1-38 of D2), termed CPMV-MAST1 and PVX-MAST8, respectively. Mice and rats were imm unized subcutaneously with CPMV-MAST1 and mice with PVX-MAST8 in adjuvant a nd high titres of FnBP-specific antibody were obtained. The mouse IgG was p redominantly of the IgG(2a) and IgG(2b) isotypes, which strongly bound comp lement component Clq, suggesting a TH1-bias in the peptide-specific respons es. Sera from mice and rats immunized with CPMV-MAST1 and from mice immuniz ed with PVX-MAST8 were shown to completely inhibit the binding of fibronect in to immobilised recombinant FnBP and rat sera against CPMV-MAST1 were abl e to block adherence of S. aureus to fibronectin. These studies demonstrate that the D2 peptide is highly immunogenic when expressed on 2 different pl ant viruses and highlight the potential of plant virus-based vaccines to pr otect against S, aureus infections. (C) 1999 Elsevier Science Ltd. All righ ts reserved.