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Bactericidal/permeability-increasing protein promotes complement activation for neutrophil-mediated phagocytosis on bacterial surface
- Source :
- Immunology. 103:519-525
- Publication Year :
- 2001
- Publisher :
- Wiley, 2001.
-
Abstract
- The neutrophil bactericidal/permeability-increasing protein (BPI) has both bactericidal and lipopolysaccharide-neutralizing activities. The present study suggests that BPI also plays an important role in phagocytosis of Escherichia coli by neutrophils through promotion of complement activation on the bacterial surface. Flow cytometric analysis indicated that fluorescein-labelled E. coli treated with BPI were phagocytosed in the presence of serum at two- to five-fold higher levels than phagocytosis of the bacteria without the treatment. In contrast, phagocytosis of the fluoresceined bacteria with or without treatment by BPI did not occur at all in the absence of serum. The phagocytosis stimulated by BPI and serum was dose-dependent. The effect of BPI on phagocytosis in the presence of serum was not observed on Gram-positive bacteria (Staphylococcus aureus). Interestingly, the complement C3b/iC3b fragments were deposited onto the bacterial surface also as a function of the BPI concentration under conditions similar to those for phagocytosis. Furthermore, the BPI-promoted phagocytosis was blocked completely by anti-C3 F(ab')(2) and partially by anti-complement receptor (CR) type 1 and/or anti-CR type 3. These findings suggest that BPI accelerates complement activation to opsonize bacteria with complement-derived fragments, leading to stimulation of phagocytosis by neutrophils via CR(s).
- Subjects :
- Blood Bactericidal Activity
Neutrophils
Phagocytosis
Immunology
Dose-Response Relationship, Immunologic
Macrophage-1 Antigen
Biology
medicine.disease_cause
Cell Line
Microbiology
Escherichia coli
medicine
Humans
Immunology and Allergy
Complement Activation
Membrane Proteins
Blood Proteins
Complement C3
Original Articles
Opsonin Proteins
Bactericidal/permeability-increasing protein
biology.organism_classification
humanities
Culture Media
Complement system
Staphylococcus aureus
Complement C3b
Receptors, Complement 3b
biology.protein
iC3b
Bacteria
Antimicrobial Cationic Peptides
Subjects
Details
- ISSN :
- 13652567 and 00192805
- Volume :
- 103
- Database :
- OpenAIRE
- Journal :
- Immunology
- Accession number :
- edsair.doi.dedup.....7a81f7b4b1b02923ca6393cdb26b5226