The effects of asbestos inhalation on the distribution and enhancement of immunoassociated antigen expression of alveolar macrophage subpopulation.
We have studied the effects of in vivo asbestos exposure on the surface immune-associated (Ia) antigen expression and distribution of alveolar macrophage subpopulations defined by continuous iso-osmotic Percoll gradients (density range: 1.006 to 1.123 g/ml) using a rat model of asbestos inhalation. Two groups of rats were exposed by intermittent inhalation (6 hr/day for 5 days/week over 4 weeks) to either amphibole (crocidolite) or serpentine (chrysotile) asbestos. A group of control rats was sham-exposed to clean air only. Alveolar macrophages from rats of three groups were obtained by bronchoalveolar lavage. During exposure, distinct differences appeared within 7 days of asbestos exposure, and some of these findings persisted in the crocidolite-exposed group for as long as 2 to 5 months after the cessation of exposure. Furthermore, relatively greater proportions of Ia-antigen positive cells were detected in several density fractions obtained from both asbestos-exposed groups (especially the crocidolite-exposed group). Multinucleated alveolar macrophages were seen frequently in all Percoll fractions after both types of asbestos inhalation. A significant proportion of multinucleated alveolar macrophages in these fractions expressed surface Ia-antigen positivity. The finding of enriched numbers of higher-density phagocytes in bronchoalveolar lavage cell subpopulations from asbestos-exposed rats may reflect the presence of newly recruited-immature monocytes and/or macrophages at sites of intrapulmonary asbestos deposition. Also, increased proportions of Ia-antigen positive cells suggest that a part of them were functionally activated.
Inamoto
T
T
Department of Animal Microbiology and Parasitology, Faculty of Agriculture, Tohoku University, Sendai, Japan.
Georgian
M M
MM
Kagan
E
E
Ogimoto
K
K
D000280:Administration, Inhalation; D000818:Animals; D001194:Asbestos / Q000494:pharmacology*; D017638:Asbestos, Crocidolite; D017632:Asbestos, Serpentine; D001195:Asbestosis / Q000276:immunology* / Q000473:pathology; D002499:Centrifugation, Density Gradient; D004195:Disease Models, Animal; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis* / Q000187:drug effects; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000276:immunology* / Q000473:pathology; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344
D017632:Asbestos, Serpentine; D000949:Histocompatibility Antigens Class II; D017638:Asbestos, Crocidolite; D001194:Asbestos