02033nas a2200373   4500000000100000008004100001260001600042653001200058653001500070653001400085653001400099653001400113653000800127653001100135653002100146653003000167653001200197653001600209653000900225653002300234653001500257653002500272653002600297100001300323700001500336700001800351245009500369856006800464300001200532490000800544050001600552520107700568022001401645       2010                            d  c2010 Jun 0110aAnimals10aAnnexin A510aApoptosis10aCaspase 310aCaspase 910aDNA10aFemale10aFluorescent Dyes10aIn Situ Nick-End Labeling10aIndoles10aMacrophages10aMice10aMice, Inbred C57BL10aMice, Nude10aMycobacterium leprae10aStaining and Labeling1 aLahiri R1 aRandhawa B1 aKrahenbuhl JL00aInfection of mouse macrophages with viable Mycobacterium leprae does not induce apoptosis.  uhttp://jid.oxfordjournals.org/content/201/11/1736.full.pdf+html  a1736-420 v201  aLAHIRI 20103 a<p>The role played by apoptosis in host response to Mycobacterium leprae is unclear. Here, we studied in vitro induction of apoptosis in mouse bone marrow-derived macrophages infected with live and irradiated M. leprae, as a function of multiplicity of infection under permissive (33 degrees C) and nonpermissive (37 degrees C) temperatures. The infected macrophages were scored for apoptosis by using DAPI (4',6-diamindino-2-phenylindole dihydrochloride) and Annexin V staining, along with activated Caspases 3 and 9 and TUNEL (terminal dUTP nick end labeling) assay. Our results show that, in contrast to uninfected cells, murine macrophages infected with live M. leprae demonstrated little, if any, apoptosis, even when macrophages had a heavy burden of live leprosy bacilli. In contrast, elevated levels of apoptosis were observed when macrophages were infected with irradiated M. leprae. The results strongly suggest that the viability and purity of the leprosy bacilli used for in vitro studies determines the extent of apoptosis observed in infected host cells.</p>  a1537-6613