A human transferrin-binding protein ofStaphylococcus aureusis immunogenic in vivo and has an epitope in common with human transferrin receptor

Abstract

To understand human immune responses against the human transferrin-binding protein of Staphylococcus aureus (SA-tbp), we examined cell wall proteins from S. aureus ATCC 6538 using human convalescent sera, and a monoclonal antibody specific for human transferrin receptor (McAb-HTR). The SA-tbp, detected by immunoblot assay, was iron-repressible, reacted with the convalescent sera, and cross-reacted with McAb-HTR. Immunoelectron microscopy probed with McAb-HTR showed a reaction zone around the test strain from the deferrated BHI. After being preincubated with an S. aureus-bacteremic serum, the electroblot of the SA-tbp still reacted with McAb-HTR, but not with human transferrin-horseradish peroxidase conjugate. We conclude, there are at least two kinds of epitopes in the SA-tbp; one able to bind to human transferrin is immunogenic in humans, but the other sharing epitopes common with human transferrin receptor is not immunogenic in humans.

Proteome Analysis of Membrane and Cell Wall Associated Proteins from Staphylococcus aureus

“…In contrast, lysostaphin (a glycylglycine endopeptidase from Staphylococcus stapholyticus) enzymatically cleaves the pentaglycine cross bridges of the staphylococcal peptidoglycan, predominantly at their central glycine residue. 39 Lysostaphin treatment has been used in a number of studies for the isolation of cell wall components such as penicillin binding proteins, transferrin-binding proteins [40][41][42] and also for identifying vaccine candidate antigens using proteome analysis. 29 In the present study, we found lysis of staphylococcal cells by lysostaphin provided the most detailed 2DE gels making it an effective, reproducible and relatively easy extraction method for the preparation of membrane and cell wall associated proteins.…”