Experimental murine leprosy. 3. Early local reaction to mycobacterium lepraemurium in C3H and C57/BL mice.

M. lepraemurium was injected subcutaneously into two inbred strains of mice, C3H and C57/BL, in order to study the local reaction at various time intervals. Within 6 hours an acute inflammatory reaction developed at the site of injection. In the course of the following days it was replaced by a mononuclear infiltrate. The influx of mononuclear cells appeared to be somewhat greater in C57/BL than in C3H mice. Apart from this, little difference was observed between the two strains until at 4 weeks when a vigorous granulomatous reaction developed in the C57/BL strain. This reaction apparently arrested further local spread of the infection. The histological appearance of the inflitrate indicated that a delayed hypersensitivity reaction was taking place. No signs of such reaction was observed in the C3H strain.