Provided is the use of an immunotherapeutic agent comprising cell wall fragments of a virulent strain of Mycobacterium tuberculosis-complex (MTB-C) for the preparation of a drug for the prophylactic treatment of tuberculosis, wherein said agent is obtained by a method comprising the following steps: - cultivate the virulent MTB-C strain over a period equal to or greater than three weeks and, subsequently, - homogenate the cell culture in the presence of a nonionic surfactant, - separating the non-fragmented cells and the solubilized components by means of centrifugation, - subjecting the fraction of cell wall fragments to chemical or physical treatment to inactivate the eventual virulent strain cells that it eventually contains, and - optionally drying the obtained immunotherapeutic agent by means of lyophilisation.
