Mr. Hirvonen et al., EFFECT OF VIABILITY OF ACTINOMYCETE SPORES ON THEIR ABILITY TO STIMULATE PRODUCTION OF NITRIC-OXIDE AND REACTIVE OXYGEN SPECIES IN RAW264.7MACROPHAGES, Toxicology, 124(2), 1997, pp. 105-114
Spores of actinomycetes, mesophilic gram-positive bacteria, isolated f
rom moldy houses, induced the expression of inducible NO-synthase (iNO
S) with a subsequent NO-production in RAW264.7 macrophages. No differe
nces were detected between production of nitric oxide (NO) by alive or
irradiated spores of different strains of Actinomycetes sp. or Strept
omyces sp. Moreover, a significant production of reactive oxygen speci
es (ROS) occurred in the macrophages after their stimulation both by a
live and irradiation killed spores of actinomycetes. However, ROS-resp
onses in macrophage induced by dead spores were significantly lower co
mpared to those induced by alive spores. The cytotoxicity of the spore
s of different actinomycetes differed widely. The production of NO and
ROS did not depend directly on the viability of the spores, suggestin
g an important role for cell wall components in the activation of the
cells. (C) 1997 Elsevier Science Ireland Ltd.