Identification of immunogenic and serum binding proteins of Staphylococcus epidermidis.
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.
Sellman
Bret R
BR
Wyeth Vaccine Research, Pearl River, NY 10965, USA. sellmab@wyeth.com
Howell
Alan P
AP
Kelly-Boyd
Cari
C
Baker
Steve M
SM
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
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001798:Blood Proteins; D002352:Carrier Proteins; D011994:Recombinant Proteins