Identification of Staphylococcus aureus proteins recognized by the antibody-mediated immune response to a biofilm infection
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Date
2006-05
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Abstract
Staphylococcus aureus causes persistent, recurrent infections (e.g., osteomyelitis) by forming biofilms. To
survey the antibody-mediated immune response and identify those proteins that are immunogenic in an S.
aureus biofilm infection, the tibias of rabbits were infected with methicillin-resistant S. aureus to produce
chronic osteomyelitis. Sera were collected prior to infection and at 14, 28, and 42 days postinfection. The sera
were used to perform Western blot assays on total protein from biofilm grown in vitro and separated by
two-dimensional gel electrophoresis. Those proteins recognized by host antibodies in the harvested sera were
identified via matrix-assisted laser desorption ionization–time of flight analysis. Using protein from mechanically
disrupted total and fractionated biofilm protein samples, we identified 26 and 22 immunogens, respectively.
These included a cell surface-associated -lactamase, lipoprotein, lipase, autolysin, and an ABC transporter
lipoprotein. Studies were also performed using microarray analyses and confirmed the biofilm-specific
up-regulation of most of these genes. Therefore, although the biofilm antigens are recognized by the immune
system, the biofilm infection can persist. However, these proteins, when delivered as vaccines, may be important
in directing the immune system toward an early and effective antibody-mediated response to prevent
chronic S. aureus infections. Previous works have identified S. aureus proteins that are immunogenic during
acute infections, such as sepsis. However, this is the first work to identify these immunogens during chronic
S. aureus biofilm infections and to simultaneously show the global relationship between the antigens expressed
during an in vivo infection and the corresponding in vitro transcriptomic and proteomic gene expression levels.
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Brady RA, Leid JG, Camper AK, Costerton JW, Shirtliff ME, "Identification of Staphylococcus aureus proteins recognized by the antibody-mediated immune response to a biofilm infection," Infect Immun, 2006 74(6):3415-3426