pH6 antigen of Yersinia pestis interacts with plasma lipoproteins and cell membranes

Abstract

The bacterial pathogen Yersinia pestis expresses a potential adhesin, the pH6 antigen (pH6-Ag), which appears as fimbria-like structures after exposure of the bacteria to low pH. pH6-Ag was previously shown to agglutinate erythrocytes and to bind to certain galactocerebrosides. We demonstrate that purified pH6-Ag selectively binds to apolipoprotein B (apoB)-containing lipoproteins in human plasma, mainly LDL.

The Psa Fimbriae of Yersinia pestis Interact with Phosphatidylcholine on Alveolar Epithelial Cells and Pulmonary Surfactant

“…Psa also bound to commercial PC from egg yolk on TLC, confirming that PC is the A549 receptor for the Psa fimbriae. Interestingly, Makoveichuk et al observed that Psa interacts with the lipid moiety of plasma lipoproteins and with cell membranes (20). These results are consistent with our findings, since all the lipoproteins and liposomes that were recognized by Psa in the latter study have large surfaces exposing polar lipid heads, including the choline moiety of PC (26).…”

“…In Yersinia pseudotuberculosis, it was reported that Psa mediates bacterial binding to the epithelial cell line HEp-2 (37). In addition, purified Psa binds to apolipoprotein B-containing lipoproteins in human plasma, mainly low-density lipoprotein, and it was suggested that the lipid moiety of the lipoprotein is responsible for the interaction (20). Is has also been proposed that Psa acts as an Fc receptor for human immunoglobulin G1 (IgG1), IgG2, and IgG3 (38).…”

Role of immune response in Yersinia pestis infection

“…Recently a study reported that purified PsaA selectively bound to apolipoprotein B (apoB)-containing lipoproteins (LDL) in human plasma [32]. At concentrations close to the physiological concentration in human blood (250 g of human LDL/ml), LDL nearly abolished the interaction of the purified PsaA with macrophages; in this way the pathogens prevent the recognition by the host defense systems [32].…”

The pH 6 Antigen Is an Antiphagocytic Factor Produced byYersinia pestisIndependent ofYersiniaOuter Proteins and Capsule Antigen

“…LDL at concentrations close to the physiological concentration in human blood (250 g of human LDL per ml) almost abolished the interaction of purified PsaA with macrophages. This process could prevent recognition of the pathogen by host defense systems (25). It was suggested that immune masking might be important for the ability of the pathogen to cause disease in the susceptible host (25).…”