Mannan decelerates the clearance of human red blood cells in SCID mouse.
Mannans and its related compounds decelerated human (Hu) red blood cell (RBC)-clearance in severe combined immunodeficiency (SCID) mice by inhibiting erythro-phagocytosis of macrophages. Chimeric SCID mice for Hu-RBC which are generated by repeated transfusions with mature Hu-RBCs are described recently as a model for Plasmodium falciparum infection, though the Hu-RBC clearance in the mice at present is very rapid and the parasitemia in the mice is only erratic. Here, we aimed to study the method to decelerate Hu-RBC clearance in SCID mice, to establish a suitable mouse model for malaria parasites. Yeast and Candida mannans as well as lactoferrin, a glycoprotein containing both oligomannoside- and N-acetyllactosamine-type glycans, decelerated Hu-RBC clearance, but instead other saccharides such as carboxymethyl chitin, N-acetylglucosamine, and D-glucose did not. Yeast mannan and lactoferrin interfered significantly with in vitro Hu-RBC-phagocytosis which was also inhibited by mannopentaose and mannotoriose. D-mannose exhibited a moderate inhibitory activity. N-acetyl-D-glucosamine, however, showed only a slight inhibitory activity, but D-glucose had no inhibitory activity on Hu-RBC phagocytosis. These results may postulate that Hu-RBC clearance in SCID mouse might be mediated by receptor-ligand binding by a macrophage lectin like receptor with mannose specificity.
Ishihara
C
C
School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
Hiratai
R
R
Tsuji
M
M
Yagi
K
K
Nose
M
M
Azuma
I
I
D000117:Acetylglucosamine / Q000494:pharmacology; D000818:Animals; D002175:Candida / Q000378:metabolism; D002678:Chimera; D002686:Chitin / Q000031:analogs & derivatives / Q000494:pharmacology; D004195:Disease Models, Animal; D017707:Erythrocyte Transfusion; D004912:Erythrocytes; D005260:Female; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007781:Lactoferrin / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000502:physiology; D016778:Malaria, Falciparum / Q000097:blood; D008297:Male; D008351:Mannans / Q000494:pharmacology*; D051379:Mice; D016513:Mice, SCID; D010587:Phagocytosis / Q000187:drug effects*; D011975:Receptors, Mitogen / Q000187:drug effects; D015003:Yeasts / Q000378:metabolism
D008351:Mannans; D011975:Receptors, Mitogen; D002686:Chitin; C044872:O-(carboxymethyl)chitin; D007781:Lactoferrin; D005947:Glucose; D000117:Acetylglucosamine