Partial inhibition of the growth of Mycobacterium lepraemurium in C3H mice immunized with cell wall skeletons.

C3H mice stimulated with M. lepraemurium cell wall skeletons (LM-CWS) were challenged with viable M. lepraemurium, and delayed-type hypersensitivity (DTH) to picryl chloride was measured. In one type of experiment the mice were challenged at the time when stimulation of cell-mediated resistance by means of LM-CWS was undertaken. The major purpose was to investigate principles pertaining to immunotherapy. In contrast to the loss of a detectable DTH response to picryl chloride, development of murine leprosy was partially suppressed. In the second type of experiment the mice were stimulated with oil-attached LM-CWS seven weeks before challenge with M. lepraemurium. Findings were: a) that nonspecific DTH as measured by sensitization and challenge with picryl chloride was activated before the infection with M. lepraemurium and b) that the DTH which developed was associated with partial protection against the growth of lepromata. The murine leprosy which developed in C3H mice stimulated with LM-CWS was progressive after some delay.