02214nas a2200253   4500000000100000008004100001260001300042653001200055653001300067653001700080653002800097653001200125653000900137653002400146653002500170653001700195100001100212245007400223856007800297300001100375490000700386520155300393022001401946       1975                            d  c1975 May10aAnimals10aHindlimb10aImmunization10aImmunization, Secondary10aleprosy10aMice10aMice, Inbred BALB C10aMycobacterium leprae10aTime Factors1 aLevy L00aSuperinfection in mice previously infected with Mycobacterium leprae.  uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC415184/pdf/iai00233-0218.pdf  a1094-90 v113 a<p>Previous studies of the protection of mice by prior infection with Mycobacterium leprae in one hind footpad against challenge with M.leprae in the opposite hind footpad had produced conflicting results; therefore, the problem was restudied. In several experiments, BALB/c mice were inoculated first in the right hind footpad with 5,000 M. leprae and then challenged in the left hind footpad with 5,000 M. leprae of the same strain at intervals after primary infection, at the same time that uninfected mice were inoculated. Multiplication of the M. leprae of the secondary challenge inoculum occurred at the same rate and to the same level as multiplication in uninfected mice when challenges were made soon after primary infection. Multiplication was slowed but proceeded to the same level in previously infected as in uninfected mice when the challenges were administered between 76 and 106 days after primary infection (47 to 17 days before the M. leprae of the primary inoculum had multiplied to the level of 10-6 organisms per footpad). Finally, the M. leprae of a secondary challenge administered at the time that the organisms of the primary inoculum had multiplied to 10-6 per footpad or later not only multiplied more slowly in previously infected than in control animals, but multiplication in the previously infected animals reached a lower maximum. These results are similar to those observed when mice previously infected with M. bovis (BCG), M. marinum, Toxoplasma gondii, or Besnoitia jellisoni were challenged with M. leprae.</p>  a0019-9567