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A role for Mac-1 (CDIIb/CD18) in immune complex-stimulated neutrophil function in vivo: Mac-1 deficiency abrogates sustained Fcgamma receptor-dependent neutrophil adhesion and complement-dependent proteinuria in acute glomerulonephritis.

Tang T, Rosenkranz A, Assmann KJ, Goodman MJ, Gutierrez-Ramos JC, Carroll MC, Cotran RS, Mayadas TN - J. Exp. Med. (1997)

Bottom Line: Mac-1 (alphambeta2), a leukocyte adhesion receptor, has been shown in vitro to functionally interact with Fcgamma receptors to facilitate immune complex (IC)-stimulated polymorphonuclear neutrophil (PMN) functions.In vitro studies showed that spreading of Mac-1- PMNs to IC-coated dishes was equivalent to that of wild-type PMNs at 5-12 min but was markedly reduced thereafter, and was associated with an inability of mutant neutrophils to redistribute filamentous actin.Complement C3-deficient mice also had significantly decreased proteinuria compared to wild-type mice.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.

ABSTRACT
Mac-1 (alphambeta2), a leukocyte adhesion receptor, has been shown in vitro to functionally interact with Fcgamma receptors to facilitate immune complex (IC)-stimulated polymorphonuclear neutrophil (PMN) functions. To investigate the relevance of Mac-1-FcgammaR interactions in IC-mediated injury in vivo, we induced a model of Fc-dependent anti-glomerular basement membrane (GBM) nephritis in wild-type and Mac-1-deficient mice by the intravenous injection of anti-GBM antibody. The initial glomerular PMN accumulation was equivalent in Mac-1 and wild-type mice, but thereafter increased in wild-type and decreased in mutant mice. The absence of Mac-1 interactions with obvious ligands, intercellular adhesion molecule 1 (ICAM-1), and C3 complement, is not responsible for the decrease in neutrophil accumulation in Mac-1- deficient mice since glomerular PMN accumulation in mice deficient in these ligands was comparable to those in wild-type mice. In vitro studies showed that spreading of Mac-1- PMNs to IC-coated dishes was equivalent to that of wild-type PMNs at 5-12 min but was markedly reduced thereafter, and was associated with an inability of mutant neutrophils to redistribute filamentous actin. This suggests that in vivo, Mac-1 is not required for the initiation of Fc-mediated PMN recruitment but that Mac-1-FcgammaR interactions are required for filamentous actin reorganization leading to sustained PMN adhesion, and this represents the first demonstration of the relevance of Mac-1-FcgammaR interactions in vivo. PMN-dependent proteinuria, maximal in wild-type mice at 8 h, was absent in Mac-1 mutant mice at all time points. Complement C3-deficient mice also had significantly decreased proteinuria compared to wild-type mice. Since Mac-1 on PMNs is the principal ligand for ic3b, an absence of Mac-1 interaction with C3 probably contributed to the abrogation of proteinuria in Mac-1- mice.

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Release of LTB4  from PMNs incubated with immobilized ICs. The amount of  LTB4 released by wild-type ( )  and Mac-1–deficient ( )  PMNs incubated with ICs was  assessed over the time course  used for PMN adhesion and  spreading. LTB4 was rapidly released (within 5 min) from  PMNs adherent to ICs and accumulated over time. PMNs on  ice, adherent for 40 min to plastic or BSA (12–40 min) did not  release LTB4 demonstrating that  its release is stimulated specifically by ICs. There was no significant difference in LTB4 release between wild-type and  cells incubated with ICs. n = 3–5 experiments/time point.
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Figure 6: Release of LTB4 from PMNs incubated with immobilized ICs. The amount of LTB4 released by wild-type ( ) and Mac-1–deficient ( ) PMNs incubated with ICs was assessed over the time course used for PMN adhesion and spreading. LTB4 was rapidly released (within 5 min) from PMNs adherent to ICs and accumulated over time. PMNs on ice, adherent for 40 min to plastic or BSA (12–40 min) did not release LTB4 demonstrating that its release is stimulated specifically by ICs. There was no significant difference in LTB4 release between wild-type and cells incubated with ICs. n = 3–5 experiments/time point.

Mentions: To assess whether the decrease in PMN accumulation at 2 h is caused by inhibition of secretion of a chemoattractant by mutant PMNs, we examined the release of an arachidonic acid metabolite LTB4, since a previous study had shown that β2 integrins are required for IC-stimulated LTB4 production (21). In addition, LTB4 has been linked to the activation and morphologic polarization of PMNs and therefore may be required for sustaining PMN spreading. We measured LTB4 secreted by wild-type and mutant PMNs bound to IC-coated surfaces by an ELISA assay for murine LTB4. In wild-type PMNs, LTB4 was detected in the media at 5 min after neutrophil interaction with IC-coated surfaces and had increased 25-fold by 40 min (Fig. 6). We detected no significant differences in the amount of LTB4 released by wild-type and mutant PMNs at all time points tested, suggesting that Mac-1 is not required for LTB4 production.


A role for Mac-1 (CDIIb/CD18) in immune complex-stimulated neutrophil function in vivo: Mac-1 deficiency abrogates sustained Fcgamma receptor-dependent neutrophil adhesion and complement-dependent proteinuria in acute glomerulonephritis.

Tang T, Rosenkranz A, Assmann KJ, Goodman MJ, Gutierrez-Ramos JC, Carroll MC, Cotran RS, Mayadas TN - J. Exp. Med. (1997)

Release of LTB4  from PMNs incubated with immobilized ICs. The amount of  LTB4 released by wild-type ( )  and Mac-1–deficient ( )  PMNs incubated with ICs was  assessed over the time course  used for PMN adhesion and  spreading. LTB4 was rapidly released (within 5 min) from  PMNs adherent to ICs and accumulated over time. PMNs on  ice, adherent for 40 min to plastic or BSA (12–40 min) did not  release LTB4 demonstrating that  its release is stimulated specifically by ICs. There was no significant difference in LTB4 release between wild-type and  cells incubated with ICs. n = 3–5 experiments/time point.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211718&req=5

Figure 6: Release of LTB4 from PMNs incubated with immobilized ICs. The amount of LTB4 released by wild-type ( ) and Mac-1–deficient ( ) PMNs incubated with ICs was assessed over the time course used for PMN adhesion and spreading. LTB4 was rapidly released (within 5 min) from PMNs adherent to ICs and accumulated over time. PMNs on ice, adherent for 40 min to plastic or BSA (12–40 min) did not release LTB4 demonstrating that its release is stimulated specifically by ICs. There was no significant difference in LTB4 release between wild-type and cells incubated with ICs. n = 3–5 experiments/time point.
Mentions: To assess whether the decrease in PMN accumulation at 2 h is caused by inhibition of secretion of a chemoattractant by mutant PMNs, we examined the release of an arachidonic acid metabolite LTB4, since a previous study had shown that β2 integrins are required for IC-stimulated LTB4 production (21). In addition, LTB4 has been linked to the activation and morphologic polarization of PMNs and therefore may be required for sustaining PMN spreading. We measured LTB4 secreted by wild-type and mutant PMNs bound to IC-coated surfaces by an ELISA assay for murine LTB4. In wild-type PMNs, LTB4 was detected in the media at 5 min after neutrophil interaction with IC-coated surfaces and had increased 25-fold by 40 min (Fig. 6). We detected no significant differences in the amount of LTB4 released by wild-type and mutant PMNs at all time points tested, suggesting that Mac-1 is not required for LTB4 production.

Bottom Line: Mac-1 (alphambeta2), a leukocyte adhesion receptor, has been shown in vitro to functionally interact with Fcgamma receptors to facilitate immune complex (IC)-stimulated polymorphonuclear neutrophil (PMN) functions.In vitro studies showed that spreading of Mac-1- PMNs to IC-coated dishes was equivalent to that of wild-type PMNs at 5-12 min but was markedly reduced thereafter, and was associated with an inability of mutant neutrophils to redistribute filamentous actin.Complement C3-deficient mice also had significantly decreased proteinuria compared to wild-type mice.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.

ABSTRACT
Mac-1 (alphambeta2), a leukocyte adhesion receptor, has been shown in vitro to functionally interact with Fcgamma receptors to facilitate immune complex (IC)-stimulated polymorphonuclear neutrophil (PMN) functions. To investigate the relevance of Mac-1-FcgammaR interactions in IC-mediated injury in vivo, we induced a model of Fc-dependent anti-glomerular basement membrane (GBM) nephritis in wild-type and Mac-1-deficient mice by the intravenous injection of anti-GBM antibody. The initial glomerular PMN accumulation was equivalent in Mac-1 and wild-type mice, but thereafter increased in wild-type and decreased in mutant mice. The absence of Mac-1 interactions with obvious ligands, intercellular adhesion molecule 1 (ICAM-1), and C3 complement, is not responsible for the decrease in neutrophil accumulation in Mac-1- deficient mice since glomerular PMN accumulation in mice deficient in these ligands was comparable to those in wild-type mice. In vitro studies showed that spreading of Mac-1- PMNs to IC-coated dishes was equivalent to that of wild-type PMNs at 5-12 min but was markedly reduced thereafter, and was associated with an inability of mutant neutrophils to redistribute filamentous actin. This suggests that in vivo, Mac-1 is not required for the initiation of Fc-mediated PMN recruitment but that Mac-1-FcgammaR interactions are required for filamentous actin reorganization leading to sustained PMN adhesion, and this represents the first demonstration of the relevance of Mac-1-FcgammaR interactions in vivo. PMN-dependent proteinuria, maximal in wild-type mice at 8 h, was absent in Mac-1 mutant mice at all time points. Complement C3-deficient mice also had significantly decreased proteinuria compared to wild-type mice. Since Mac-1 on PMNs is the principal ligand for ic3b, an absence of Mac-1 interaction with C3 probably contributed to the abrogation of proteinuria in Mac-1- mice.

Show MeSH
Related in: MedlinePlus