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Intermediate monocytes in ANCA vasculitis: increased surface expression of ANCA autoantigens and IL-1β secretion in response to anti-MPO antibodies.

O'Brien EC, Abdulahad WH, Rutgers A, Huitema MG, O'Reilly VP, Coughlan AM, Harrington M, Heeringa P, Little MA, Hickey FB - Sci Rep (2015)

Bottom Line: Most patients harbour autoantibodies to myeloperoxidase (MPO) or proteinase 3 (PR3).Monocyte subsets respond differently to antibodies directed against MPO and PR3, with anti-MPO but not anti-PR3 leading to increased IL-1β, IL-6 and IL-8 production.These data suggest that monocytes, specifically, the intermediate subset, may play a role in ANCA vasculitis, and also indicate that substantial differences exist between the effect of anti-MPO and anti-PR3 antibodies on these cells.

View Article: PubMed Central - PubMed

Affiliation: Trinity Health Kidney Centre, Department of Clinical Medicine, Trinity College Dublin, St. James' Hospital Campus, Dublin 8, Ireland.

ABSTRACT
ANCA vasculitis encompasses several autoimmune conditions characterised by destruction of small vessels, inflammation of the respiratory tract and glomerulonephritis. Most patients harbour autoantibodies to myeloperoxidase (MPO) or proteinase 3 (PR3). Clinical and experimental data suggest that pathogenesis is driven by ANCA-mediated activation of neutrophils and monocytes. We investigated a potential role for distinct monocyte subsets. We found that the relative proportion of intermediate monocytes is increased in patients versus control individuals, and both MPO and PR3 are preferentially expressed on these cells. We demonstrate that MPO and PR3 are expressed independently of each other on monocytes and that PR3 is not associated with CD177. MPO expression correlates with that of Fc receptor CD16 on intermediate monocytes. Monocyte subsets respond differently to antibodies directed against MPO and PR3, with anti-MPO but not anti-PR3 leading to increased IL-1β, IL-6 and IL-8 production. In concordance with the observed higher surface expression of MPO on intermediate monocytes, this subset produces the highest quantity of IL-1β in response to anti-MPO stimulation. These data suggest that monocytes, specifically, the intermediate subset, may play a role in ANCA vasculitis, and also indicate that substantial differences exist between the effect of anti-MPO and anti-PR3 antibodies on these cells.

No MeSH data available.


Related in: MedlinePlus

Fc receptor binding is not required for anti-MPO-induced IL-1β production by monocytes.CD14+ monocytes were isolated from PBMCs of healthy control individuals by MACS separation. Cells were incubated with 2.5 μg/1 × 106 cells Fc Block @ 37 °C for 30 minutes followed by stimulation for 4 hours with 5 μg/ml of either monoclonal antibody (mAb) directed against MPO or an isotype control. Supernatants were then removed and levels of IL-1β measured by ELISA. Data are presented as the median and interquartile range. Statistical analysis was performed using Two-way ANOVA and Sidak test to correct for multiple comparisons (**p < 0.01).
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f8: Fc receptor binding is not required for anti-MPO-induced IL-1β production by monocytes.CD14+ monocytes were isolated from PBMCs of healthy control individuals by MACS separation. Cells were incubated with 2.5 μg/1 × 106 cells Fc Block @ 37 °C for 30 minutes followed by stimulation for 4 hours with 5 μg/ml of either monoclonal antibody (mAb) directed against MPO or an isotype control. Supernatants were then removed and levels of IL-1β measured by ELISA. Data are presented as the median and interquartile range. Statistical analysis was performed using Two-way ANOVA and Sidak test to correct for multiple comparisons (**p < 0.01).

Mentions: It has been shown previously that the binding of the Fc portion of ANCA antibodies to neutrophils is required for their activation10. This finding, along with our own finding that the Fc receptor (CD16) expression on monocytes correlates with expression of MPO led us to investigate whether blocking the Fc receptor would abrogate the effect of anti-MPO stimulation in monocytes. In order to test this hypothesis we treated cells with anti-MPO mAb after pre-treatment with either commercially available Fc blocking solution or vehicle. Monocyte activation was measured by IL-1β production. Treatment with Fc blocking solution had no effect on the ability of anti-MPO mAb to activate monocytes (Fig. 8).


Intermediate monocytes in ANCA vasculitis: increased surface expression of ANCA autoantigens and IL-1β secretion in response to anti-MPO antibodies.

O'Brien EC, Abdulahad WH, Rutgers A, Huitema MG, O'Reilly VP, Coughlan AM, Harrington M, Heeringa P, Little MA, Hickey FB - Sci Rep (2015)

Fc receptor binding is not required for anti-MPO-induced IL-1β production by monocytes.CD14+ monocytes were isolated from PBMCs of healthy control individuals by MACS separation. Cells were incubated with 2.5 μg/1 × 106 cells Fc Block @ 37 °C for 30 minutes followed by stimulation for 4 hours with 5 μg/ml of either monoclonal antibody (mAb) directed against MPO or an isotype control. Supernatants were then removed and levels of IL-1β measured by ELISA. Data are presented as the median and interquartile range. Statistical analysis was performed using Two-way ANOVA and Sidak test to correct for multiple comparisons (**p < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493694&req=5

f8: Fc receptor binding is not required for anti-MPO-induced IL-1β production by monocytes.CD14+ monocytes were isolated from PBMCs of healthy control individuals by MACS separation. Cells were incubated with 2.5 μg/1 × 106 cells Fc Block @ 37 °C for 30 minutes followed by stimulation for 4 hours with 5 μg/ml of either monoclonal antibody (mAb) directed against MPO or an isotype control. Supernatants were then removed and levels of IL-1β measured by ELISA. Data are presented as the median and interquartile range. Statistical analysis was performed using Two-way ANOVA and Sidak test to correct for multiple comparisons (**p < 0.01).
Mentions: It has been shown previously that the binding of the Fc portion of ANCA antibodies to neutrophils is required for their activation10. This finding, along with our own finding that the Fc receptor (CD16) expression on monocytes correlates with expression of MPO led us to investigate whether blocking the Fc receptor would abrogate the effect of anti-MPO stimulation in monocytes. In order to test this hypothesis we treated cells with anti-MPO mAb after pre-treatment with either commercially available Fc blocking solution or vehicle. Monocyte activation was measured by IL-1β production. Treatment with Fc blocking solution had no effect on the ability of anti-MPO mAb to activate monocytes (Fig. 8).

Bottom Line: Most patients harbour autoantibodies to myeloperoxidase (MPO) or proteinase 3 (PR3).Monocyte subsets respond differently to antibodies directed against MPO and PR3, with anti-MPO but not anti-PR3 leading to increased IL-1β, IL-6 and IL-8 production.These data suggest that monocytes, specifically, the intermediate subset, may play a role in ANCA vasculitis, and also indicate that substantial differences exist between the effect of anti-MPO and anti-PR3 antibodies on these cells.

View Article: PubMed Central - PubMed

Affiliation: Trinity Health Kidney Centre, Department of Clinical Medicine, Trinity College Dublin, St. James' Hospital Campus, Dublin 8, Ireland.

ABSTRACT
ANCA vasculitis encompasses several autoimmune conditions characterised by destruction of small vessels, inflammation of the respiratory tract and glomerulonephritis. Most patients harbour autoantibodies to myeloperoxidase (MPO) or proteinase 3 (PR3). Clinical and experimental data suggest that pathogenesis is driven by ANCA-mediated activation of neutrophils and monocytes. We investigated a potential role for distinct monocyte subsets. We found that the relative proportion of intermediate monocytes is increased in patients versus control individuals, and both MPO and PR3 are preferentially expressed on these cells. We demonstrate that MPO and PR3 are expressed independently of each other on monocytes and that PR3 is not associated with CD177. MPO expression correlates with that of Fc receptor CD16 on intermediate monocytes. Monocyte subsets respond differently to antibodies directed against MPO and PR3, with anti-MPO but not anti-PR3 leading to increased IL-1β, IL-6 and IL-8 production. In concordance with the observed higher surface expression of MPO on intermediate monocytes, this subset produces the highest quantity of IL-1β in response to anti-MPO stimulation. These data suggest that monocytes, specifically, the intermediate subset, may play a role in ANCA vasculitis, and also indicate that substantial differences exist between the effect of anti-MPO and anti-PR3 antibodies on these cells.

No MeSH data available.


Related in: MedlinePlus