Table 4.
Human neutrophil states: adhesion, chemotaxis, apoptosis and function
| PMN state | PMN receptors | PMN functions |
| Circulating PMN (resting bloodstream PMN, collected by venipuncture) | Adhesion receptors: constitutive expression of L-selectin, PECAM-1 Chemoattractant receptors: constitutive expression of IL-8 receptor A, IL-8 receptor B, C5aR Apoptosis receptors: constitutive expression of TNF-α receptor I, Fas, FasL |
PMN–EC interactions: baseline PMN rolling, adhesion on activated endothelium and transmigration Chemotaxis: will undergo chemotaxis to PMN-specific and leukocyte nonspecific chemoattractants Function: minimal PMN respiratory burst (ROI•) and microbicidal activity (proteolytic enzymes) Apoptosis: constitutive apoptosis (PMN half-life ~6 h) |
| Primed PMN (PMN stimulated with priming agent in vitro) | Adhesion receptors: increased expression of CD11b, L-selectin, PECAM-1, ↔FMLPr Chemoattractant receptors: ?IL-8 receptor A, ?IL-8 receptor B, ↔C5aR Apoptosis receptors: ?TNF-α receptor I, ?Fas, ?FasL Other: CD14, PAFr ↑LTB4r, ↑PAFr |
PMN–EC interactions: unclear impact on rolling, adhesion, diapedesis Chemotaxis: no change in chemotaxis Function: when activated, display increased respiratory burst and microbicidal activity after activation Apoptosis: delayed constitutive apoptosis |
| Activated PMN (PMN stimulated with activating agent in vitro) | Adhesion receptors: ↑ CD11b, ↑ FMLPr, ?L-selectin, PECAM-1 Chemoattractant receptors: IL-8 receptor A, ↓↓ IL-8 receptor B, ↔C5aR Apoptosis receptors: unknown Other: ↓ C3br, ↓ 1C3b |
PMN–EC interactions: ↑ PMN rolling and adhesion, ?transmigration Chemotaxis: ↔chemotaxis to C5a, LTB4/ZAS; ↑ ?chemotaxis to FMLP Function: ↑ respiratory burst (ROI•) and microbicidal activity (proteolytic enzymes); ↑ phagocytosis Apoptosis: delayed apoptosis |
| Exudate PMN (PMN collected from dermal exudate milieu in vivo) | Adhesion receptors: ↑ CD11b, ↑ Mac-1, ↓ L-selectin, ↓ PECAM-1 Chemoattractant receptors: ↓ IL-8 receptor A, ↓ IL-8 receptor B, ↑ C5ar Function: ↑ FMLPr Apoptosis receptors: ↓ binding to TNF-α, ?↓ TNF receptor I, ↔Fas, FasL |
PMN–EC interactions: unknown Chemotaxis: ↑ baseline chemotaxis, ↓ chemotaxis to IL-8, ↑ chemotaxis to C5a Function: ↑ respiratory burst (ROI•), ↑ microbicidal activity and phagocytosis Apoptosis: ↓ constitutive apoptosis; ↓ TNF-α-induced, but not Fas-induced apoptosis |
| Septic PMN (PMN collected from circulation in septic patients in vivo) | Adhesion receptors: ↓ L-selectin, ?CD11b, ?FMLPr, ?PECAM-1 Chemoattractant receptors: ↓ IL-8 receptor A, ↓ IL-8 receptor B, ↓ C5aR Apoptosis receptors: ↓ TNF-α receptor I, ?Fas, ?FasL |
PMN–EC interactions: unknown Chemotaxis: ↓ chemotaxis to IL-8 and C5a Function: ? ↑ respiratory burst (ROI•), ?↑ microbicidal activity and phagocytosis Apoptosis: ↓ constitutive apoptosis; ↓ TNF-α-induced, but not Fas induced, apoptosis |
| Unresponsive or apoptotic PMN | Adhesion receptors: ↓ L-selectin, ?CD11b, ?PECAM-1 Chemoattractant receptors: unknown Apoptosis receptors: ? ↓ TNF receptor I, ?Fas, ?FasL Other: ↓ PAFr |
PMN–EC interactions: no interaction Chemotaxis: ↓ chemotaxis Function: ↓ respiratory burst (ROI•), ↓ phagocytosis Apoptosis: unresponsive PMN undergo apoptosis. and apoptotic PMN are unresponsive |
?, unknown/controversial; EC, endothelial cell; FasL, Fas ligand; FMLP, f-Met-Leu-Phe; LT, leukotriene; PAF, platelet-activating factor; PECAM, platelet–endothelial cell adhesion molecule; PMN, polymorphonuclear leukocyte; ROI, reactive oxygen intermediates; TNF, tumor necrosis factor; ZAS, zymosan activated serum.