Binding ofCoprococcus comesto the Fc portion of IgG. A possible role in the pathogenesis of Crohn's disease?

摘要

AbstractPrevious studies have shown that the fecal flora of Patients with Crohn's disease (CD) differed from the flora of healthy subjects by a higher number of anaerobic grampositive coccoid rods. Sera from patients with CD agglutinated four strains of coccoid rods (Me44, C18, Me46 and Me47) more frequently and stronger than sera from healthy subjects and patients with other diseases. One of these bacteria,Coprococcus comesstrain Me46, was not ingested by neutrophils after coating with specific IgG. In the present study, therefore, the binding of IgG and of Fab and Fc fragments to the four coccoid rods was investigated using immunofluorescence and absorption techniques. Results were compared with those obtained withStaphylococcus aureusstrain Cowan I and showed that Me46, likeS. aureus, bound (nonspecifically) IgG through its Fc portion whereas strain Me47 bound IgG through the Fab portion. Possible implications of the findings for CD are discussed.