Related Experiment Videos
Ligation of selectin L and integrin CD11b/CD18 (Mac-1) induces release of gelatinase B (MMP-9) from human neutrophils
Objective And Design:
To examine whether ligation of the adhesive receptors - selectin L and Mac-1 on the neutrophil surface could induce gelatinase B exocytosis.
Materials:
Neutrophils were isolated from fresh heparinized blood of human donors by Gradisol G centrifugation and hypotonic lysis of erythrocytes.
Methods:
Integrin CD1 1b/CD18 and selectin L mediated adhesive interaction of human neutrophils were mimicked by binding antibodies to these receptors on the surface of isolated leukocytes. Neutrophils (5 x 10(6)/ml) were incubated with antibodies against selectin L (40/microg/ml) and CD18 or CDI 1b (10microg/ml). The secretion of gelatinase was examined by determination of enzyme activity and gelatin substrate zymography of cell supernatants.
Results:
Ligation of selectin L, CD18 and CD11b integrin subunits by monoclonal antibodies induced a rapid release of 24.6+/-1.8% (p<0.005), 24.0+/-2.9% (p<0.001) and 22.7+/-2.0% (p < 0.005) of total neutrophil gelatinase, respectively as compared with 11.1+/-1.6% in the control. These values were equivalent to N-formyl-methionylleucyl-phenylalanine (fMLP)-stimulated secretion of gelatinase. Under these experimental conditions there was no significant beta-glucuronidase release from azurophilic granules. Gelatinase exocytosis elicited by selectin L and CD18 ligation was inhibited by 82.7+/-10.1% and 49.3+/-5.9%, respectively after preincubation of the neutrophils with 10 microM herbimycin A.
Conclusions:
Ligation of selectin L and integrin CD11b/ CD18 provides stimulatory signals to neutrophils which induce secretion of gelatinase B that may facilitate their transmigration into sites of inflammation.