Human platelet aggregation by Yersinia pseudotuberculosis is mediated by invasin.
Plasmid-free strains of Yersinia pseudotuberculosis induce aggregation of human platelets in vitro. It appears that this phenomenon is mediated by invasin (Inv), a 103-kDa outer membrane protein that permits bacteria to penetrate mammalian cells, since (i) an isogenic inv-deficient mutant failed to aggregate platelets compared with the parental strain; (ii) a monoclonal antibody directed against invasin inhibited platelet aggregation; (iii) Inv+ Escherichia coli HB101 promoted platelet aggregation. Platelet receptors for invasin were identified by using a panel of anti-platelet glycoprotein monoclonal antibodies in a bacterial adhesion assay. We found that bacteria bind to platelet membrane glycoproteins Ic and IIa. Electron microscopic study of bacterium-platelet interactions also revealed that bacteria expressing invasin attach to and are phagocytized by thrombocytes, in contrast to inv-deficient bacteria, indicating that these anucleated cells are able to internalize bacteria in vitro after specific interaction with invasin.
Simonet
M
M
Laboratoire de Microbiologie, Faculté de Médecine Necker-Enfants Malades, Paris, France.
Triadou
P
P
Frehel
C
C
Morel-Kopp
M C
MC
Kaplan
C
C
Berche
P
P
D018829:Adhesins, Bacterial; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000633:toxicity*; D006801:Humans; D066298:In Vitro Techniques; D010587:Phagocytosis; D010974:Platelet Aggregation; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D016029:Receptors, Very Late Antigen / Q000378:metabolism; D015011:Yersinia pseudotuberculosis / Q000472:pathogenicity*
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D010980:Platelet Membrane Glycoproteins; D016029:Receptors, Very Late Antigen; C053476:invasin, Yersinia