Isolation of a group-specific polysaccharide from tissues infected with Mycobacterium leprae.

Investigation of the immunologically active substance in Mycobacterium Zeprae has been hampered because of the unavail ability of pure cultures. However, this difficulty can now be circumvented in part by taking advantage of the identification of the group-specific antigen, Polysaccharide I (PolyINb ), present in Nocardia and Mycobacteria ( I. 3 G. 8) . This has been chemically characterized as a polymer of D-arabofuranose and D-galactopyranose in a molar ratio 3:1 (4) . The present paper deals with the identification of the group-specific polysaccharide (PolyINb ) in extracts of human leproma, after physical removal and enzymatic destruction of all other components that might have been immunologically active.