Endocytosis of cigarette-smoke condensate by rabbit alveolar macrophages in vitro measured as fluorescence intensity.
It has previously been shown that alveolar macrophages (AMs) from smokers have increased fluorescence compared to AMs from nonsmokers. In the present investigation, AMs lavaged from rabbits were exposed to a cigarette-smoke condensate (CSC) in order to study its influence on the fluorescence of AMs. Flow cytofluorometry was used. Alveolar cells exposed to 0.01% of CSC showed a fluorescence which increased with higher concentrations of the CSC. Incubation with CSC for 5 min was enough to give a significant rise (p less than 0.001) in cell fluorescence compared to controls. After incubating fluorescent cells with untreated non-fluorescent AMs, fluorescent material was distributed to the non-fluorescent AMs within 30 min. Further more, fluorescence decreased when exposed cells were cultured in CSC-free medium. When incubating CSC with blood leucocytes, an almost threefold increase in fluorescence was observed among the phagocytic cells at 37 degrees C compared to 4 degrees C, whereas the fluorescence in the non-phagocytic cell population only showed a minor enhancement. Endocytosis of fluorescent material in CSC can explain the strong fluorescence seen in AMs from smokers. Exocytosis and re-endocytosis of the material by new AMs may explain the slow decline in the fluorescence of AMs observed after cessation of smoking.
Sköld
C M
CM
Dept of Thoracic Medicine, Karolinska Hospital, Stockholm, Sweden.
Eklund
A
A
Hed
J
J
Hernbrand
R
R
D000818:Animals; D002478:Cells, Cultured; D004705:Endocytosis; D005260:Female; D005434:Flow Cytometry; D005453:Fluorescence; D066298:In Vitro Techniques; D016676:Macrophages, Alveolar / Q000502:physiology*; D008297:Male; D010947:Plants, Toxic; D011817:Rabbits; D012906:Smoke; D014026:Nicotiana
D012906:Smoke