Conglutinin is a high molecular-weight lectin originally detected in bovine serum. It belongs to the family of collectins that bind sugar residues in a Ca(2+)-dependent manner and are effector molecules in innate immunity. Conglutinin appears to play an important role in immune defense mechanisms, showing antiviral and antibacterial activities when tested in vivo and in vitro. The present study evaluated the effect of conglutinin on the respiratory bursts in bovine peripheral phagocytes. Using nitroblue tetrazolium and hydrogen peroxide assays, we showed that sugar ligand-bound conglutinin stimulated the production of superoxide and H2O2 in granulocytes whereas the non-sugar-bound form of conglutinin inhibited these processes. These results indicate that both forms of conglutinin are able to interact with surface leukocyte receptors but have opposite effects on phagocytic activity. Our findings suggest that conglutinin bound to sugar residues on microbial surfaces can induce oxygen burst in phagocytes, and thereby mediates the elimination of pathogens and prevents the spread of infection.
Animals ; Cattle/*immunology ; Collectins/*pharmacology ; Enzyme-Linked Immunosorbent Assay/veterinary ; Female ; Granulocytes/*drug effects/immunology ; Hydrogen Peroxide/immunology ; Immunity, Innate/drug effects/immunology ; Phagocytosis/immunology ; Reactive Oxygen Species/*immunology ; Respiratory Burst/*drug effects/immunology ; Serum Globulins/*pharmacology ; Statistics, Nonparametric ; Superoxides/immunology

This study was to explore the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on neutrophil morphology, function and phenotype in patients with acute leukemia undergoing chemotherapy. Neutrophil morphology was observed under microscope with oil immersion; phagocytotic function was examined by measuring the amount of hydrogen peroxide produced by neutrophil; chemotaxis was analyzed by agarose method; oxidative burst was analyzed by flow cytometry using immunofluorescence technique; neutrophil phenotype was analyzed by flow cytometry and immunofluorescence techniques. The results showed that after rhG-CSF administration, the increased "toxic" granulation, vacuoles and Döhle bodies were observed in neutrophils of patients with acute leukemia. Compared with normal control, the functions of phagocytosis, chemotaxis, oxidative burst of neutrophil were impaired after chemotherapy, while these functions were enhanced and returned to normal level or even to be exceeded after administration of rhG-CSF. In patients with acute leukemia the neutrophil presented significantly higher expression of CD64 and CD62L than that in normal control, and a mild increase of CD64 expression and significant increase of CD62L expression were found in patients after rhG-CSF treatment. No modifications of CD16, CD32, CD14 and CD11b expression were detected in these patients before or after G-CSF administration. It is concluded that rhG-CSF administration can modify the morphology, function and phenotype of neutrophils in the patients with acute leukemia undergoing chemotherapy, and these modifications of neutrophil behavior may be supposed to be a reason for the enhancement of organism anti-infection ability.
Acute Disease ; Adult ; Aged ; Chemotaxis ; drug effects ; Female ; Flow Cytometry ; Fluorescent Antibody Technique ; Granulocyte Colony-Stimulating Factor ; therapeutic use ; Humans ; Immunophenotyping ; L-Selectin ; analysis ; Leukemia ; blood ; drug therapy ; pathology ; Male ; Middle Aged ; Neutrophils ; drug effects ; immunology ; pathology ; Phagocytosis ; drug effects ; Receptors, IgG ; analysis ; Recombinant Proteins ; Respiratory Burst ; drug effects