SUPEROXIDE ANION RELEASE BY ALVEOLAR MACROPHAGES EXPOSED TO RESPIRABLE INDUSTRIAL FIBERS - MODIFYING EFFECT OF FIBER OPSONIZATION

Phagocyte-derived free radicals are considered to play a role in fibre -related pathology and the components of the lung lining fluid could m odify the surface of fibres. Therefore we examined the ability of long amosite asbestos and a range of man-made fibres to stimulate release of superoxide anion from rat alveolar macrophages when they were in th eir native form (unopsonised) and opsonised by incubation in rat Immun oglobulin G. We also assessed the specific amount of opsonin adsorbed to each fibre type. In the uncoated form all of the fibres produced mo dest amounts of superoxide release from macrophages. When they were op sonised however there was an effect on stimulation of release of super oxide that was fibre-specific. Both MMVF21 and RCF 1 were dramatically enhanced in their ability to stimulate release and this was related t o a high affinity of their surface for IgG. Code 100/475 and SiC were not substantially affected by opsonisation and this was reflected in t heir low affinity for IgG. Long amosite had low affinity for IgG but s howed dramatic enhancement of capacity to stimulate superoxide release . These fibre-specific differences in the effect of a coating of mater ial that is found in the lung lining points out the problems of interp retation of in vitro data and more work on this important area is warr anted.