Hello,

I am doing a research project on the production of purified protein derivative used in TB tests. From my research there are many methods but not enough information on what one particular company does. I know that the protein is extracted from Johnston human strain of

M. tuberculosis var. hominis and then expressed in E. coli. Does anyone know how we go from M. tuberculosis to PPD for TB tests? Which methods are used? Such as materials, media, mass spectrometry, incubation times, methods of concentration and purification procedures? Any help will be appreciated.

Thank you.