title: Preparation of tuberculin antigen L.
abstract: The preparation of antigen L using culture filtrates of live BCG is described. The procedure consisted essentially of precipitating this filtrate with 10% trichloroacetic acid in the presence of N-butyl alcohol 4% final concentration. The precipitate was chromatographed on carboxy-methyl-trisacryl-M and then on DEAE-trisacryl-M; in both cases, maximal biological activity (delayed-type hypersensitivity) was found in the void volume. The product thus obtained was chromatographed on a molecular sieve so as to eliminate poorly active fractions. The final product was 30-fold more active on guinea-pigs sensitized with live BCG than on those sensitized with inactivated BCG.
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology / Q000302:isolation & purification*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006168:Guinea Pigs; D007525:Isoelectric Focusing; D014373:Tuberculin / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D014373:Tuberculin; C032774:antigen L