The identification of target structures is a prerequisite for the developme
nt of new treatment options, like antibody based therapy, against methicill
in resistant Staphylococcus aureus (MRSA). In this study we identified immu
nodominant structures which were expressed in vivo during sepsis caused by
MRSA. Using human sera we compared the immune response of humans with MRSA
sepsis with the immune response of normal individuals and asymptomatically
colonized individuals. We identified and characterized four staphylococcal
specific antigenic structures. One target is a staphylococcal protein of 29
kDa that exhibited 29% identity to secreted protein SceA precursor of Stap
hylococcus carnosus. The putative function of this protein, which was desig
nated IsaA (immunodominant staphylococcal antigen), is unknown. The second
target is an immunodominant protein of 17 kDa that showed no homology to an
y currently known protein. This immunodominant protein was designated IsaB.
The third and fourth antigens are both immunodominant proteins of 10 kDa.
One of these proteins showed 100% identity to major cold shock protein CspA
of S. aureus and the other protein was identified as the phosphocarrier pr
otein Hpr of S. aureus. The identified immunodominant proteins may serve as
potential targets for the development of antibody based therapy against MR
SA. (C) 2000 Federation of European Microbiological Societies. Published by
Elsevier Science B.V. All rights reserved.