Limits...
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: 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.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.

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

PMN adhesion to ICs. Isolated wild-type (squares) or Mac-1–  (diamonds) PMNs were incubated with BSA–anti-BSA ICs (A) or BSA  alone (B), and fixed and stained with Wright-Giemsa. The percentage of  adhesion (i.e., the percentage of control that was set as 100% for the adhesion to IC present at 5 min in wild-type cells) was similar in cells of both  genotypes at 5 and 12 min but decreased significantly in Mac-1– cells  at 25 and 40 min. No difference was seen between the percentage of  wild-type and  cells adherent to BSA alone. n = 7 experiments. *P  <0.005, #P <0.05 compared to wild-type cells.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2211718&req=5

Figure 4: PMN adhesion to ICs. Isolated wild-type (squares) or Mac-1– (diamonds) PMNs were incubated with BSA–anti-BSA ICs (A) or BSA alone (B), and fixed and stained with Wright-Giemsa. The percentage of adhesion (i.e., the percentage of control that was set as 100% for the adhesion to IC present at 5 min in wild-type cells) was similar in cells of both genotypes at 5 and 12 min but decreased significantly in Mac-1– cells at 25 and 40 min. No difference was seen between the percentage of wild-type and cells adherent to BSA alone. n = 7 experiments. *P <0.005, #P <0.05 compared to wild-type cells.

Mentions: We examined adhesion and spreading of wild-type and Mac-1– PMNs on IC-coated surfaces. To mimic the GBM–anti-GBM interactions in vitro, slides were coated with BSA–anti-BSA IgG complexes. The IC-coated surfaces were incubated with resting peripheral blood PMNs isolated from wild-type and mice (under static conditions) in the absence of serum, thus eliminating potential effects of complement in the assay. The total number of adherent cells was measured at 5, 12, 25, and 40 min. A similar analysis was conducted on PMNs incubated with BSA-coated surfaces alone to discern effects due to BSA from those that were IC-specific. A time course of total binding of PMNs to IC-coated surfaces revealed that initial adhesion to IC, within 5 and 12 min after addition of PMNs, was similar in mutant and wild-type mice (Fig. 4). At 25 and 40 min, wild-type PMNs continued to accumulate on the IC, leading to a >50% increase over that seen at 12 min. In Mac-1– PMNs, the number of IC-adherent PMNs remained the same over a similar time course. Incubation times >40 min did not lead to further enhancement in numbers of adherent PMNs in either wild-type or mutant samples (data not shown). The number of wild-type and mutant PMNs adherent to BSA at 5 or 40 min was similar in wild-type and cells, suggesting that the observed Mac-1–mediated effects are specific for IC-coated surfaces (Fig. 4).


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)

PMN adhesion to ICs. Isolated wild-type (squares) or Mac-1–  (diamonds) PMNs were incubated with BSA–anti-BSA ICs (A) or BSA  alone (B), and fixed and stained with Wright-Giemsa. The percentage of  adhesion (i.e., the percentage of control that was set as 100% for the adhesion to IC present at 5 min in wild-type cells) was similar in cells of both  genotypes at 5 and 12 min but decreased significantly in Mac-1– cells  at 25 and 40 min. No difference was seen between the percentage of  wild-type and  cells adherent to BSA alone. n = 7 experiments. *P  <0.005, #P <0.05 compared to wild-type cells.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 4: PMN adhesion to ICs. Isolated wild-type (squares) or Mac-1– (diamonds) PMNs were incubated with BSA–anti-BSA ICs (A) or BSA alone (B), and fixed and stained with Wright-Giemsa. The percentage of adhesion (i.e., the percentage of control that was set as 100% for the adhesion to IC present at 5 min in wild-type cells) was similar in cells of both genotypes at 5 and 12 min but decreased significantly in Mac-1– cells at 25 and 40 min. No difference was seen between the percentage of wild-type and cells adherent to BSA alone. n = 7 experiments. *P <0.005, #P <0.05 compared to wild-type cells.
Mentions: We examined adhesion and spreading of wild-type and Mac-1– PMNs on IC-coated surfaces. To mimic the GBM–anti-GBM interactions in vitro, slides were coated with BSA–anti-BSA IgG complexes. The IC-coated surfaces were incubated with resting peripheral blood PMNs isolated from wild-type and mice (under static conditions) in the absence of serum, thus eliminating potential effects of complement in the assay. The total number of adherent cells was measured at 5, 12, 25, and 40 min. A similar analysis was conducted on PMNs incubated with BSA-coated surfaces alone to discern effects due to BSA from those that were IC-specific. A time course of total binding of PMNs to IC-coated surfaces revealed that initial adhesion to IC, within 5 and 12 min after addition of PMNs, was similar in mutant and wild-type mice (Fig. 4). At 25 and 40 min, wild-type PMNs continued to accumulate on the IC, leading to a >50% increase over that seen at 12 min. In Mac-1– PMNs, the number of IC-adherent PMNs remained the same over a similar time course. Incubation times >40 min did not lead to further enhancement in numbers of adherent PMNs in either wild-type or mutant samples (data not shown). The number of wild-type and mutant PMNs adherent to BSA at 5 or 40 min was similar in wild-type and cells, suggesting that the observed Mac-1–mediated effects are specific for IC-coated surfaces (Fig. 4).

Bottom Line: 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.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.

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