Comparative testing of the potency of different PPD preparations.
The potency of different PPD preparations, obtained from M. tuberculosis and M. bovis was investigated in the guinea-pig test. The groups of animals were immunized with dried mycobacterium powder (obtained from M. tuberculosis, M. bovis and M. tuberculosis + M. bovis), suspended in sterile liquid paraffin oil and with BCG vaccine. The potency tests were carried out according to the WHO requirements. Independently of the immunization method, a significantly greater potency of homologous versus heterologous PPD could not be demonstrated. The mixed PPD preparation (obtained from M. tuberculosis + M. bovis) was fractionated on SEPHAROSE 6 B and SEPHACRYL S 200 column. The potency of different fractions compared to the non-fractionated material was determined in the guinea-pig tests. The animals were immunized by dried mycobacterium powder (obtained from M. tuberculosis + M. bovis), suspended in sterile liquid paraffin oil. The IU content of fractions was calculated according to their protein N content, compared to the non-fractionated material. In these experimental conditions PPD fractions with significantly greater potency than the non-fractionated material could not be found. As a final conclusion we suggest that the desired improvement of tuberculosis diagnostics can be achieved not only by using PPDs derived from different mycobacteria but by further immunochemical purification of the tuberculin preparations and extensive testing of the purified materials in human beings as well.
D000818:Animals; D006168:Guinea Pigs; D006968:Hypersensitivity, Delayed; D009163:Mycobacterium bovis / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011786:Quality Control; D013045:Species Specificity; D014373:Tuberculin / Q000008:administration & dosage / Q000592:standards*
D014373:Tuberculin