The Susceptibility to Leprosy Bacilli of Various Inbred Strains of Mice

Abstract

Comparative observations were made of the susceptibility of various inbred mouse strains (DDD, C3H, C57BL/6, BALB/C, CF#1, CFW, RR, A, NC, SS, KK and fm) to hind foot pad infection with leprosy bacilli (N-ANETa strain, originally isolated by Shepard) under the same dietary and environmental conditions.
There were no remarkable differences, such as observed in response to subcutaneous infection with murine leprosy bacilli, in the susceptibility among these strains. Pattyn examined the multiplication of leprosy bacilli in foot pads of 5 strains of mice, and reported that some differences appeared among the experimental animals, but he interpreted that these differences were due to small differences in the original inoculum size. This claim is generally accepted in our experiments. However significant but slight differences were verified by the following results.
1) Multiplication of acid fast bacilli in the foot pads was much slower in DDD mice than in the others.
2) In KK mice the multiplication of the bacilli occurred earlier and greater yields of the bacilli were harvested from the foot pads compared with the other mice.
3) Mice of the C57BL/6 strain showed earlier multiplication but lower yields of the bacilli than the others.