Inhibition of the rat clearance system for agalacto-orosomucoid by yeast mannans and by mannose

L-Fucose-terminated glycoconjugates are recognized by pinocytosis receptors on macrophages.

“…The enzyme was assayed by using phenolphthalein glucuronide as described by Stahl and Touster (21). Ligands were iodinated by the chloramine-T method (22) to a specific activity of [1][2][3][4][5][6][7][8][9][10] ,uCi/,ug (1 Ci = 3.7 x 10'°becquerels) as described (13).…”

“…Recognition and plasma clearance of lysosomal glycosidases (1) and mannose/N-acetylglucosamine-terminated glycoproteins (2)(3)(4)(5) are mediated by cell surface pinocytosis receptors associated with liver sinusoidal cells (6)(7)(8)(9)(10)(11) and other cells of the mononuclear phagocyte system (12)(13)(14). In vitro studies with isolated macrophages have disclosed that mannose-terminated glycoproteins bind to cell surface receptors with high affinity after which they are rapidly internalized and transported to lysosomes (11)(12).…”

Modification of the blood-brain barrier: increased concentration and fate of enzymes entering the brain.

“…Peroxidase is a glycoprotein rich in mannosyl residues. Specific receptors for mannose-terminal glycoproteins have been demonstrated in cells of non-neural tissue (25,26). The possibility exists that a similar mannosyl-specific receptor is present on neuronal membranes.…”

Receptor-mediated binding and internalization of leukocyte elastase by alveolar macrophages in vitro.

“…The work described in this report demonstrates that HLE binds rapidly and specifically to alveolar 20 The binding of HLE to macrophages is distinct from the receptor-mediated binding of mannose or N-acetyl glucosamine-terminal glycoprotein lysosomal enzymes to macrophages (10, 11), which are responsible for in vivo clearance of these substances from the extracellular space (25)(26)(27)(28)(29)(30). This distinction is demonstrated by the trypsin insensitivity of binding of HLE, by the lack of requirement for divalent cation, and by the failure of yeast mannan to inhibit binding.…”