My Beloved Neutrophil Dr Boxer 2014 Neutropenia Family Conference
The Beloved Neutrophil: Its Function in Health and Disease Stem Cell Multipotent Progenitor Myeloid Lymphoid CMP IL-3, SCF, GM-CSF CLP Committed Progenitor MEP GMP GM-CSF, IL-3, SCF EPO TPO G-CSF M-CSF IL-5 IL-3 SCF RBC Platelet Neutrophil Monocyte/ Basophil B-cells Macrophage Eosinophil T-Cells Mast cell NK cells Mature Cell Dendritic cells PRODUCTION AND KINETICS OF NEUTROPHILS CELLS % CELLS TIME Bone Marrow: Myeloblast 1 7 - 9 Mitotic Promyelocyte 4 Days Myelocyte 16 Maturation/ Metamyelocyte 22 3 – 7 Storage Band 30 Days Seg 21 Vascular: Peripheral Blood Seg 2 6 – 12 hours 3 Marginating Pool Apoptosis and ? Tissue clearance by 0 – 3 macrophages days PHAGOCYTOSIS 1. Mobilization 2. Chemotaxis 3. Recognition (Opsonization) 4. Ingestion 5. Degranulation 6. Peroxidation 7. Killing and Digestion 8. Net formation Adhesion: β 2 Integrins ▪ Heterodimer of a and b chain ▪ Tight adhesion, migration, ingestion, co- stimulation of other PMN responses LFA-1 Mac-1 (CR3) p150,95 a2b2 a CD11a CD11b CD11c CD11d b CD18 CD18 CD18 CD18 Cells All PMN, Dendritic Mac, mono, leukocytes mono/mac, PMN, T cell LGL Ligands ICAMs ICAM-1 C3bi, ICAM-3, C3bi other other Fibrinogen other GRANULOCYTE CHEMOATTRACTANTS Chemoattractants Source Activators Lipids PAF Neutrophils C5a, LPS, FMLP Endothelium LTB4 Neutrophils FMLP, C5a, LPS Chemokines (a) IL-8 Monocytes, endothelium LPS, IL-1, TNF, IL-3 other cells Gro a, b, g Monocytes, endothelium IL-1, TNF other cells NAP-2 Activated platelets Platelet activation Others FMLP Bacteria C5a Activation of complement Other Important Receptors on PMNs ñ Pattern recognition receptors – Detect microbes - Toll receptor family - Mannose receptor - bGlucan receptor – fungal cell walls ñ Cytokine receptors – enhance PMN function - G-CSF, GM-CSF - TNF Receptor ñ Opsonin receptors – trigger phagocytosis - FcgRI, II, III - Complement receptors – ñ Mac1/CR3 (CD11b/CD18) – C3bi ñ CR-1 – C3b, C4b, C3bi, C1q, Mannose binding protein From JG Hirsch, J Exp Med 116:827, 1962, with permission.
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