Antibody response to the extracellular adherence protein (Eap) of Staphylococcus aureus in healthy and infected individuals.
The extracellular adherence protein (Eap) from Staphylococcus aureus has been suggested as a vaccine candidate and for therapeutic use due to its immunomodulating and antiangiogenic properties; however, little is known about anti-Eap antibodies in humans. We determined anti-Eap antibody titers by enzyme-linked immunosorbent assay and Western blot and measured serum samples from 92 patients with proven S. aureus infections and 93 healthy controls. The functionality of antibodies was assessed by a phagocytosis assay using Eap-coated fluorescent microspheres. Antibodies were detected in all human samples, but not in mice. Patients showed significantly higher titers than controls [immunoglobulin M (IgM), P=0.007; IgG, P<0.0001]. Patients with deep or severe infections showed higher titers than those with superficial or mild disease. Eap alone was sufficient to promote phagocytosis by peripheral blood mononuclear cell and granulocytes that was moderately enhanced in the presence of human serum, but no correlation was found with the levels of anti-Eap antibodies. Anti-Eap antibodies are prevalent in all tested humans and correlate with the severity of S. aureus infection; however, they do not seem to provide protection against invasive infections. Before considering Eap for therapy or as a vaccine candidate, further studies are warranted to assess the impact of the interference between Eap and its specific antibodies.
Institute of Medical Microbiology and Hygiene, Saarland University Hospital, Homburg, Germany. insa.joost@uk-koeln.de
Insa
I
Joost
Susanne
S
Jacob
Olaf
O
Utermöhlen
Uwe
U
Schubert
Joseph M
JM
Patti
Mei-Fang
MF
Ong
Jürgen
J
Gross
Christoph
C
Justinger
Jörg H
JH
Renno
Klaus T
KT
Preissner
Markus
M
Bischoff
Mathias
M
Herrmann
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D010587:Phagocytosis; D016601:RNA-Binding Proteins / Q000276:immunology*; D013203:Staphylococcal Infections / Q000276:immunology* / Q000382:microbiology / Q000503:physiopathology*; D013211:Staphylococcus aureus / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; C444739:Eap-N protein, Staphylococcus aureus; D016601:RNA-Binding Proteins