Previous Article | Next Article ![]()
Infect. Immun., Feb 1997, 537-543, Vol 65, No. 2
Q Sun, GM Smith, C Zahradka and MJ McGavin
A fibronectin-binding protein (FnBP) adhesin of Staphylococcus aureus
possesses three 37- or 38-amino-acid motifs (D1, D2, and D3) that can each
bind fibronectin (Fn) with low affinity and that in tandem comprise D1-3, a
high-affinity Fn-binding domain. To identify epitopes for the generation of
adhesion-blocking antibodies, rabbits were immunized with recombinant D1-3
or with a glutathione S-transferase fusion protein, GSTD1-3.
Affinity-purified antibodies from the D1-3 immunization were poor
inhibitors of Fn binding to S. aureus and recognized several different
epitopes, with a preference for clusters of acidic amino acids that do not
contribute to Fn binding. Antibodies generated with GSTD1-3 as an immunogen
were more effective inhibitors, but concentrations in excess of 20 microg x
ml-1 did not promote more than 50% inhibition. These antibodies were highly
specific for amino acids 21 to 34 of D1 (D1(21-34)), which contain a
sequence that is essential for Fn binding and are identical to D2 at 12 of
14 residues. Neither antibody preparation recognized D3(20-33) of the D3
motif, where the only homology to D1(21-34) and D2(21-34) comprises a
sequence motif, GG(X3,4)(I/V)DF, that is critical to Fn binding. However,
antibodies specific for both D1(21-34) and D3(20-33) could be obtained by
using synthetic peptides corresponding to these sequences as immunogens.
F(ab')2 fragments derived from these antibodies each caused 40 to 50%
inhibition of Fn binding to S. aureus, and their ability to bind to
purified FnBP was eliminated by competing Fn. However, mixtures of the two
F(ab')2 preparations did not provide additive or synergistic inhibition of
Fn binding. Therefore, inhibition of Fn binding to S. aureus requires
antibodies specific for D1(21-34) and D3(20-33), but a mixture of
antibodies specific for both sequences did not provide complete inhibition.
Copyright © 1997, American Society for Microbiology
Identification of D motif epitopes in Staphylococcus aureus fibronectin- binding protein for the production of antibody inhibitors of fibronectin binding
Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|