BINDING AND DEGRADATION OF LACTOFERRIN BY PORPHYROMONAS-GINGIVALIS, PREVOTELLA-INTERMEDIA AND PREVOTELLA-NIGRESCENS

The ability of laboratory and clinical strains of Polphyromonas gingiv alis, Prevotella intermedia and Prevotella nigrescens to bind and to d egrade lactoferrin (Lf) has been assessed. Lf bound readily to whole c ells of each species apparently via a high-affinity site and one or mo re low-affinity sites. P. gingivalis showed a lower affinity for Lf th an the other two species (P < 0.001). Virtually all strains of P. ging ivalis completely degraded Lf under the conditions employed, whereas P . intermedia and P. nigrescens showed only partial degradation. These data suggest that Lf binds to a high-affinity receptor on all these ba cteria and, particularly in the case of P. gingivalis, is then degrade d by cell-associated proteases. This property may provide protection t o the cell against the effects of Lf in periodontal sites and so is a possible virulence factor in disease. There was no association between the ability to degrade Lf and whether the strains had originated from healthy or diseased oral sites.