A histochemical study about the involvement of rat liver cells in the uptake of heterologous immune comples from the circulation

Abstract

Intravenously injected immune complexes (ICx) composed of bovine serum albumin (BSA) and rabbit anti-BSA were taken up by the liver. Insoluble complexes, made in antibody excess, were rapidly taken up by Kupffer cells and were metabolized within 24 h. Soluble complexes, made in antigen excess, were only partly taken up by Kupffer cells. In addition these complexes were bound, taken up and metabolized by endothelial cells. Until 2 h after injection soluble complexes could also be observed along the microvilli of hepatocytes. No signs of endocytosis in hepatocytes could be observed. It is concluded, that ICx can be taken up by Kupffer cells as well as by endothelial cells. The physical state of the complexes, soluble or insoluble, determines the cell type in which uptake occurs.

The Scavenger Function of Liver Sinusoidal Endothelial Cells in Health and Disease

“…Skogh et al (1985) then reported that radiolabeled large, soluble immune complexes of dinitrophenylated (DNP)conjugated HSA complexed by IgG distributed to Kupffer cells, whereas smaller complexes of lightly DNP-conjugated HSA complexed with IgG were taken up mainly by LSECs in rats (Skogh et al, 1985). The uptake of large immune complexes in Kupffer cells and small immune complexes in LSECs was also reported by others (van der Laan-Klamer et al, 1985.…”

“…These are formed in the blood circulation when either antibody or antigen is present in excess (Nydegger, 2007), and their clearance in LSECs via the FcγRIIb2 provides a way to remove IgG immune complexes without risk of proinflammatory activation (Anania et al, 2019). Larger complexes are phagocytosed by Fc receptors expressed on macrophages (Skogh et al, 1985;van der Laan-Klamer et al, 1985.…”

FcγRIIb on Liver Sinusoidal Endothelium Clears Small Immune Complexes

“…The LSEC, according to the literature, is a vigorous scavenger of blood stream detritus, expressing a variety of surface receptors for blood-borne material, displaying abundant coated vesicles and lysosomes appropriate for a disposal mechanism(45), and in our hands eliminating blood-borne virus with remarkable efficiency(12). Further, the uptake of IC by LSEC has been well documented by others (4, 13, 16, 46). We note parenthetically that FcγR-expressing endothelium has been found elsewhere only in the human placenta, and there too the isoform expressed is RIIb(28).…”

Kupffer cell depletionin vivoresults in preferential elimination of IgG aggregates and immune complexes via specific Fc receptors on rat liver endothelial cells

“…Within the liver, the liver macrophages (Kupffer cells, KC) are considered to be responsible for IC clearance (Benacerraf, Sebestyen & Cooper, 1959; Rifai & Mannik, 1984;Bogers et al, 1990 Very recently it has been reported that endothelial cells (EC) in rat and human liver sections are able to bind IgG-IC in vitro (Muro et al, 1987). Furthermore, in tiro studies reported binding of IgG-IC to liver EC (Skogh et al, 1985;Van Der Laan-Klamer et al, 1985, 1986bMuro etal., 1987). Despite the lack of Fc receptors on EC of ordinary blood vessels (Ryan et al, 1980;Shingu et al, 1981), the binding of IgG-IC to liver EC seems to be mediated by Fc receptors (Pulford & Souhami, 1981;Van Der Laan-Klamer et al, 1986a;Muro et al, 1987).…”