Group A streptococcal isolate 64/14 expresses surface plasmin-binding structures in addition to Plr.
A recombinant plasmin receptor (Plr) gene product originally cloned from group A streptococcal isolate 64/14 was analysed for its ability to bind plasmin(ogen) and to account for all the surface plasmin-binding properties of streptococcal isolate 64/14. Functional analysis of recombinant Plr demonstrated that the protein exhibited equal reactivity with human Lys-plasmin and Lys-plasminogen, but significantly lower reactivity with Glu-plasminogen. Plasmin-binding was both inhibitable and elutable by lysine or lysine analogs, and active plasmin bound to recombinant Plr was not neutralized by alpha 2-antiplasmin. Thus, the plasmin-binding properties of recombinant Plr correlated with the plasmin-binding phenotype of the intact streptococcal isolate 64/14. In addition, fluid-phase recombinant Plr could completely inhibit binding of plasmin to either immobilized recombinant Plr or group A streptococcal isolate 64/14 with equal efficiency, indicating that surface-expressed Plr could account for all the plasmin-binding properties of the intact organism. An IgM monoclonal antibody to recombinant Plr that specifically recognized a surface structure on streptococcal isolate 64/14 significantly inhibited the binding of plasmin to the recombinant protein; however, the antibody was not successful at inhibiting plasmin-binding to the intact bacteria, indicating the presence of other plasmin-binding structures on the bacterial surface in addition to Plr.
Department of Microbiology, Medical College of Ohio, Toledo 43699-0008, USA.
S S
SS
D'Costa
H
H
Wang
D W
DW
Metzger
M D
MD
Boyle
D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000918:Antibody Specificity; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology / Q000378:metabolism*; D001426:Bacterial Proteins; D005341:Fibrinolysin / Q000378:metabolism; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016253:Microscopy, Immunoelectron; D010641:Phenotype; D010958:Plasminogen / Q000276:immunology / Q000378:metabolism; D018000:Receptors, Peptide / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D007075:Immunoglobulin M; C101055:Plr protein, Streptococcus; D018000:Receptors, Peptide; D011994:Recombinant Proteins; D010958:Plasminogen; D005341:Fibrinolysin