Binding of human plasminogen and lactoferrin by Helicobacter pylori coccoid forms

Abstract

The interactions between Helicobacter pylori spiral and coccoid forms, extracellular matrix (ECM) and plasma proteins were studied in an 125I-labelled protein assay. The range of binding of collagen V, plasminogen, human lactoferrin (HLf) and vitronectin to coccoid forms of H. pylori NCTC 11637 was 26-48%. In contrast, binding of radiolabelled fibronectin and collagen types I and III was low (3-8%). The coccoid forms of 14 strains of H. pylori showed significant HLf binding (median 26%). With plasminogen, no significant difference was found between binding to the coccoid (median = 13%) and spiral (median = 12%) forms, of 13 of the 14 strains of H. pylori tested; the exception was strain NCTC 11637. 125I-plasminogen showed a dose-dependent binding to both the coccoid and spiral forms. Plasminogen binding to both forms was specific; the binding was inhibited by non-labelled plasminogen, plasmin, lysine, EACA (epsilon-aminocaproic acid) but not by fetuin or various carbohydrates. Similarly, HLf binding was found to be specific and was inhibited by non-labelled HLf and BLf. The coccoid forms showed either similar or enhanced ECM binding capabilities compared with the spiral forms. As the binding of ECM proteins may be an important mechanism of tissue adhesion for various pathogenic bacteria, the coccoid differentiated form of H. pylori can be considered as an infective form in the pathogenesis of helicobacter infection and type B gastritis.

Morphologic Conversion of Helicobacter Pylori from Spiral to Coccoid Form: Scanning (SEM) and Transmission Electron Microscopy (TEM) Suggest Viability

“…Adhesion with pedestal formation was seen between H. pylori coccoid and epithelial cells [ 19, 3 11 as well as in a Balb/cA mice H.pylori infection model [32]. Plasminogen and lactoferrin bind to the coccoid form of Helicobacter, and also to extracellular matrix protein considered to be an important mechanism for tissue adhesion [20].…”

Interleukin-8 induction and adhesion of the coccoid form of Helicobacter pylori

“…Khin et al [14] reported that the extracellular matrix and plasma proteins have the ability to bind to both helical and coccoid forms of H. pylori to a similar extent in an 125 I-labelled protein assay. Furthermore, it was shown that the binding of these proteins to both forms was inibited in the presence of non-labelled protein.…”

Helicobacter pylori Interactions with Host Serum and Extracellular Matrix Proteins: Potential Role in the Infectious Process

“…For example, H. pylori expresses ECM-binding molecules during the stationary phase of growth. For specific ECM molecules, it was observed that both coccoidal and spiral forms of the organism express binding to a similar extent (39). When studying the interactions of bacteria with the ECM, it is important to grow the bacteria under in vivo-like conditions since pH, redox potential, divalent cations, and iron availability could represent important factors for their expression (49).…”

“…This bacteria is extremely motile, even in viscous environments like the gastric mucus, by virtue of one to six polar sheathed flagella (73). When exposed to a hostile environment or other high-stress conditions, the bacterium transforms from its spiral highly motile form to a coccoid form (39). H. pylori was first cultured in vitro and shown to be associated with gastritis and peptic ulcers by Marshall (54) and Warren (109).…”