Adherence of a virulent strain of Listeria monocytogenes to the surface of a hepatocarcinoma cell line via lectin-substrate interaction.

Listeria monocytogenes was examined for the presence of surface carbohydrates to ascertain whether surface sugars, if present, would interact with eucaryotic surface carbohydrate receptors. We found that a virulent, but not two avirulent strains had a surface alpha-D-galactose residue as determined by agglutination with Griffonia simplicifolia (GS-I) and other lectins. The virulent strain bound to a human hepatocarcinoma cell line (HepG2), which has a well characterized receptor for alpha-D-galactose. This interaction could be blocked by pretreatment of the HepG2 cells with either alpha-D-galactose or neuraminidase, the latter of which will render the galactose receptor functionally inactive. We propose that the attachment of the virulent Listeria to eucaryotic cells occurs as a result of the interaction of the microbial alpha-D-galactose with that of the eucaryotic galactose receptor. This surface carbohydrate may provide an explanation for the mechanism of attachment and penetration of virulent Listeria into host cells during infection. As such, this may allow for amplification of pathogenesis through intracellular multiplication in nonprofessional phagocytes prior to macrophage involvement.