1970 Volume 39 Issue 1 Pages 7-16
This study was carried out to examine the minimum inoculum, the differences in the strain, sex and age of mice, and the multiplication of M. lepraemurium in the hind footpads of mice and hamsters which had been treated with thymectomy, thymectomy plus the administration of immunosuppressive agents, injection of Freund's imcomplete adjuvant, and gamma-ray irradiation (approximately 1200 rad) in thymectomized mice.
The strain of mice used were ICR, SW/A, CF#I, ddY-F and dd, and the hamsters used were the golden hamster.
The results obtained are summarized as follows:
1) The minimum inoculum was approximately 5.0×102 bacilli per each hind footpad.
2) Nodular swelling in the hind footpad of the mice was occasionally greater in the male than in the female, but that of the hamsters was less in the male than in the female, as was true in thymectomized hamster. Also, the differences for the age of 4 weeks (adults) and that of 6-8 months (old) in the female mouse were less in the old than in the adult. Furthermore, no significant difference was observed between the CF#I strain of mice and the others.
3) In the thymectomized mice and hamsters, leproma-formation in the hind footpad was inhibited at an early stage after the inoculation, but accelerated at a later stage after the inoculation. This difference was apparently observed in the neonatally thymectomized mice. In addition, leproma-formation was strongly inhibited by the administration of antilymphocytic serum (ALS).
4) The effect of immunosuppressive agents on the multiplication of M. lepraemurium was apparent in the testosterone propionate or progesterone-administration, but such other agents as Cortisone, Thyroxine, Pituitary hormone, Reserpine, Hydroxyurea, Mitomycin C, 5-Fluorouracil and 6-Mercaptopurine, did not show good results in our investigation. However, in the case of the hamsters leproma-formation was inhibited by the administration of progesterone.
5) The count of M. lepraemurium and leproma-formation in the footpads was strongly inhibited by an injection of an adjuvant and by gamma-irradiation.
It may be concluded from these results that the multiplication of M. lepraemurium in the footpad of mice and hamsters was mainly influenced by the presence or absence of immunity, i.e., the depression of circulating lymphocyte levels in the granuloma formation.
