Flow cytometric isolation and phenotypic characterization of two subsets of ED2(+) (CD163) hepatic macrophages in rats.
OBJECTIVE
Macrophages in the liver are well known for their functional heterogeneity. However, subpopulations of the hepatic macrophages are not well defined.


METHODS
Two subsets of hepatic macrophages isolated from rats via FACS with immunolabeling of ED2 (anti-CD163) antibody were studied for phenotypic and functional characteristics.


RESULTS
A subset showed an ED2(high) and autofluorescence(high) (ED2(high)/AF(high)) phenotype, exhibiting characteristics consistent with the description of the Kupffer cells (KC). A second subset, displaying an ED2(dim)/AF(dim) phenotype, was smaller in size, monocyte-like and weak in phagocytosis. Transmission electron microscopy demonstrated that both subsets are phagocytes. Quantitative RT-PCR revealed that in addition to expression of macrophage-related surface markers such as CD14, ED1 (CD68), fucose receptor, and CD163, the ED2(dim)/ AF(dim) cells expressed mRNA encoding for myeloid lineage differentiation markers ERMP12 (PECAM) and ERMP20 (Ly-6C). These two subsets exhibited differential in gene expression of selected cytokines, extracellular matrix proteinases, and Toll-like receptor in normal livers, as well as significantly upregulated expression in cholestatic livers induced by bile duct ligation.


CONCLUSIONS
The data suggest that the ED2(high)/AF(high) population of the liver cells represent the conventional Kupffer cells. The ED2(dim)/AF(dim) cells, however, are small hepatic resident macrophages characteristically different from the conventional Kupffer cells.
He
Yao
Y
Comprehensive Transplant Center, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Sadahiro
Tomohito
T
Noh
Sang-Ik
SI
Wang
Hong
H
Todo
Tsuyoshi
T
Chai
Ning-Ning
NN
Klein
Andrew S
AS
Wu
Gordon D
GD