Jmw. Vanhaarst et al., DENDRITIC CELLS AND THEIR PRECURSORS ISOLATED FROM HUMAN BRONCHOALVEOLAR LAVAGE - IMMUNOCYTOLOGIC AND FUNCTIONAL-PROPERTIES, American journal of respiratory cell and molecular biology, 11(3), 1994, pp. 344-350
Human bronchoalveolar lavage (BAL) has been described to contain, besi
des a large number of alveolar macrophages (AM) (similar to 95%), smal
l numbers of monocyte-like cells (similar to 2%) and dendritic cells (
DC) (similar to 0.4%). To separate AM (high autofluorescence) from DC,
we used a fluorescence activated cell sorter (FACS) to separate BAL c
ells into a low autofluorescent (LAF) fraction and a high autofluoresc
ent (HAF) fraction. Immunocytologic and functional properties of these
fractions were investigated. The LAF fraction was composed of acid ph
osphatase (APh)- and RFD9-negative cells, which were strongly positive
for HLA-DR, L25, RFD1, and CD68. A portion of these cells expressed C
D1a (22%) and My4 (60%). The marker pattern of these cells is reminisc
ent to that of intraepithelial bronchial DC and to that of blood DC, T
he majority of the LAF cells had a monocyte-like morphology, but after
overnight culture the percentage of LAF cells with long cytoplasmic e
xtensions (DC morphology) was strongly augmented (from 18 to 51%). The
HAF fraction contained 100% AM, strongly positive for APh, HLA-DR, CD
68, RFD7, and RFD9. In culture, the LAF cells formed clusters with T c
ells and vigorously stimulated the proliferation of allogeneic T cells
and naive (CD45RO-negative) T cells. BAL and LAF cells produced highe
r responses in nonsmokers than in smokers. In contrast, HAF cells did
not form clusters with T cells and did not stimulate allogeneic T cell
proliferation. HAF cells even suppressed mitogen-driven T cell prolif
eration. We conclude that human BAL cells can be separated with a FACS
into (1) high autofluorescent AM with T cell-suppressive properties a
nd (2) low autofluorescent accessory cells with a very strong T cell-s
timulatory potential. These accessory cells show many features of dend
ritic cells, but do have some monocyte characteristics as well.