title: Identification of immunogenic and serum binding proteins of Staphylococcus epidermidis.
abstract: Staphylococcus epidermidis is a commensal of human skin and a leading cause of nosocomial bloodstream infections. Limited information is available about S. epidermidis proteins that are expressed upon transition to the bloodstream or those involved in host-pathogen interactions. A cell surface fraction from S. epidermidis 0-47 grown in rabbit serum to mimic environmental signals encountered during a bloodstream infection was separated by two-dimensional (2D) gel electrophoresis. Following 2D separation, the proteins were transferred to nitrocellulose and detected with either pooled sera generated in rabbits immunized with live S. epidermidis 0-47 or with biotin-labeled serum proteins eluted from the surface of bacteria grown in rabbit serum. Twenty-nine immunoreactive or serum binding proteins of S. epidermidis were identified by mass spectrometry. Twenty-seven of the corresponding genes were expressed in Escherichia coli, and the purified recombinant proteins were used to immunize mice. In a preliminary screen, 12 of the 27 recombinant proteins induced a response that reduced the number of bacteria recovered from the spleen or bloodstream of infected mice. In subsequent vaccination studies, 5 of the 12 proteins resulted in a statistically significant reduction in the number of bacteria. The identification of five candidate vaccine antigens from the initial screen of only 29 proteins demonstrates the utility of this approach.
authors.affiliation: Wyeth Vaccine Research, Pearl River, NY 10965, USA. sellmab@wyeth.com
authors.forename: Bret R
authors.initials: BR
authors.lastname: Sellman
authors.forename: Alan P
authors.initials: AP
authors.lastname: Howell
authors.forename: Cari
authors.initials: C
authors.lastname: Kelly-Boyd
authors.forename: Steve M
authors.initials: SM
authors.lastname: Baker
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000097:blood* / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000097:blood* / Q000235:genetics / Q000276:immunology*; D001798:Blood Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood / Q000235:genetics / Q000276:immunology*; D002473:Cell Wall / Q000276:immunology; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics; D013058:Mass Spectrometry; D051379:Mice; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D044967:Serum / Q000276:immunology; D013154:Spleen / Q000382:microbiology; D013212:Staphylococcus epidermidis / Q000254:growth & development / Q000276:immunology*; D014611:Vaccination
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001798:Blood Proteins; D002352:Carrier Proteins; D011994:Recombinant Proteins