Isolation of a peptido-polysaccharide from the dermatophyte Epidermophyton floccosum and a study of its reaction with human C-reactive protein and a mouse anti-phosphorylcholine myeloma serum.

Culture filtrate extracts from a number of dermatophyte and Aspergillus species precipitate with human C-reactive protein (CRP) and the lectin Con A. Using immobilized Con A, a peptidopolysaccharide (PPS) has been isolated from Epidermophyton floccosum culture filtrate by affinity chromatography and shown to precipitate with Con A, human CRP sera and a mouse myeloma serum with specificity for phosphorylcholine (PC). The PPS contains carbohydrate (60%), protein (35%), choline and phosphate. The carbohydrate portion consists almost entirely of D-mannose with only 2% hexosamine. Amino acid analysis revealed that serine, threonine, proline and glycine accounted for over 50% of the total amino acids present. Precipitation of E. floccosum PPS and pneumococcal C substance with human CRP sera and mouse anti-PC serum were compared in quantitative precipitin studies. Inhibition studies demonstrated that PC is a potent inhibitor of the serum CRP-PPS and myeloma protein-PPS precipitation reactions. The involvement of 'C substances' in a variety of biological processes is discussed.