Monoclonal antibodies to Staphylococcus aureus laminin-binding proteins cross-react with mammalian cells

Abstract

We and others have previously shown that some microorganisms, including bacteria, express on their surfaces receptors that specifically recognize extracellular matrix proteins, such as laminin, fibronectin, or both. The ability of microorganisms to adhere and to invade might depend on the existence of receptors which could, thus, be correlated with pathogenicity. In the present paper, we report the isolation of five stable cell lines that were producers of monoclonal antibodies to Staphylococcus aureus laminin receptors. One of these antibodies, which was of the immunoglobulin M isotype, blocked the binding of laminin to bacteria before and after fixation and recognized the putative 52-kilodalton laminin-binding protein in whole bacterial extracts. Also, purified receptor was isolated by immunoaffinity chromatography and shown to bind laminin. Furthermore, the same antibodies bound the 67-kilodalton putative receptor from mouse melanoma cells and gave positive immunofluorescence reactions against mammalian tumor cells. These data strongly suggest either the evolutionary conservation of at least some sequences in both procaryotic and eucaryotic laminin-binding proteins or convergent evolution and positive selection of epitopes cross-reacting with laminin. Some of these antibodies to the procaryotic protein could therefore become useful markers for the expression of laminin receptors by cancer cells.

Binding of staphylococci to mucus in vivo and in vitro

“…The FM-binding receptor of S. aureus was sensitive to trypsin treatment and resistant to treatment with ,-galactosidase and sodium metaperiodate (Table 4), which suggests that the receptor has a protein component. At present it is unknown whether this mucin-binding receptor is similar to previously described surface proteins of S. aureus that mediate binding to fibrinogen (18), fibronectin (24), laminin (42), collagen (29), influenza A virus-infected and control cell monolayers (15,51), the Fc piece of immunoglobulins (22), or silicone polymers (4). Surface proteins of other bacteria have been reported as receptors for mucin binding.…”

Binding of heparan sulfate to Staphylococcus aureus

“…The binding of heparan sulfate to S. aureus V8 does not appear to be mediated by any of the staphylococcal surface proteins so far described, since the Mrs of the heparan sulfate-binding proteins differ from those of other described staphylococcal adhesins. The apparent affinity of the heparan sulfate-binding proteins for their ligand is considerably lower than those of the staphylococcal adhesins which bind fibrinogen (4), fibronectin (25), laminin (20), collagen (27,30), and thrombospondin (15), which bind their respective ligands with dissociation constants of 10-9 M (10-7 M for collagen). The observation that the dissociation constant for the binding of heparan sulfate to S. aureus V8 is relatively high suggests that if the heparan sulfate-binding proteins are important in the pathogenesis of staphylococcal infections, they promote binding of the bacteria to host cells during early stages of the disease process.…”

“…Staphylococcus aureus and other staphylococcal species capable of causing diseases in humans and animals interact with various connective tissue proteins, such as fibronectin (25,29), collagens (27,30), laminin (20), and vitronectin (22). Although the consequences of these binding phenomena for host-parasite relationships are still to be explored, they could promote staphylococcal adherence to host tissues.…”

The Adhesion of Protein A‐Bearing Staphylococcus aureus Organisms to Soluble‐Staphylococcal‐Antigens‐Coated HeLa Cells Mediated by Specific Antibodies

“…It is well known that S. aureus binds to various substances existing on the surface of animal cells or tissues, such as fibronectin (10,16,29,31), laminin (10,18,22,31), type IV collagen (31), vitronectin (4), fibrinogen (3,10), and such bindings are considered to play an important role in early stages of bacterial infections (17,30). Generally, SpA is one of the major components of cell wall, for example, comprising 6.7%of the cell wall fraction of S. aureus Cowan I (9), and some previous studies suggested a possibility that SpA might play a role in bacterial binding to such substances (5,31).…”