A lectin-like receptor on murine macrophage is involved in the recognition and phagocytosis of human red cells oxidized by phenylhydrazine.
Phenylhydrazine (Phz) is a powerful hemolytic agent which has several effects on both normal and G6PD deficient red blood cells (RBCs). We have studied the mechanism of removal of Phz-damaged human RBCs by murine macrophages. Phagocytosis of Phz-treated RBCs was found to be 50 RBCs/100 mac as compared to 2 RBCs/100 mac of the controls. EGTA and sodium azide inhibited the phagocytosis, indicating a requirement for both calcium ions and energy. Incubation of macrophages with sugars such as D-galactose or D-mannose reduced phagocytosis of Phz-treated RBCs by up to 60%, indicating the involvement of a macrophage lectin-like receptor in the recognition of Phz-treated RBCs. The presence of serum in the phagocytosis assay did not affect either phagocytosis of Phz-treated RBCs or inhibition by sugars. beta-Galactosidase, but not neuraminidase, treatment of RBCs caused a significant inhibition in phagocytosis of Phz-treated RBCs. These results suggest that galactosyl residues are exposed on RBC membrane during oxidation, probably not as a result of desialization. We conclude that Phz-treated RBCs are detected as damaged cells mainly due to sugar changes on their membrane, which are directly recognized by lectin-like receptors on the macrophages.
Horn
S
S
Department of Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Gopas
J
J
Bashan
N
N
D000818:Animals; D001386:Azides / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects*; D005690:Galactose / Q000494:pharmacology; D006801:Humans; D008264:Macrophages / Q000502:physiology*; D008358:Mannose / Q000494:pharmacology; D051379:Mice; D009439:Neuraminidase / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology*; D010659:Phenylhydrazines / Q000494:pharmacology*; D011975:Receptors, Mitogen / Q000502:physiology*; D019810:Sodium Azide; D001616:beta-Galactosidase / Q000494:pharmacology
D001386:Azides; D010659:Phenylhydrazines; D011975:Receptors, Mitogen; C030299:phenylhydrazine; D004533:Egtazic Acid; D019810:Sodium Azide; D009439:Neuraminidase; D001616:beta-Galactosidase; D008358:Mannose; D005690:Galactose