Tgfbr2

Recombinant human GDF15 was mainly Chinese hamster ovary (CHO) cell line-derived (Cat# 957-GD, R&D Systems/Bio-Techne, Abingdon, UK). The two lots of GDF15 that were mostly used here were later tested for TGF-β content by R&D Systems: Lot# EHF1713081 (purchased early 2014) showed 169.7 pg TGF-β per μg GDF15 and Lot# EHF0914051 (purchased late 2014) showed 0.73 pg TGF-β per μg GDF15 and all lots sold since these measurements were done had to pass a quality control of maximum 20 pg TGF-β-content per μg GDF15 (R&D Systems, personal communication). We also performed experiments with “mammalian cell culture”-derived GDF15 (Cat# 120–28, Lot# 1111S396, Peprotech, London, UK) and E. coli-derived GDF15 (Cat# ab125769, Abcam, Cambridge, UK). Other recombinant human proteins (activin A, BMP9, ALK1-Fc, ALK5-Fc, TGFBR2-Fc, TGFBR2-isotype 2-Fc ACVR2A-Fc, endoglin-Fc, TGFBR3-Fc and M-CSF) were from R&D Systems, except IL-6 (Gibco, Invitrogen, Carlsbad, CA, USA). SB431542 was from Sigma-Aldrich (St Louis, MO, USA). TGFBR2 (Cat# AF-241-NA), pan-TGF-β (Cat# AB-100-NA), and GDF15 (Cat# MAB957) neutralizing antibodies were from R&D Systems. Protein G Sepharose 4 Fast Flow (GE Healthcare, Oslo, Norway) was used in the neutralizing antibodies experiment to pull antibodies out from cell culture media.

Type-I collagenase, and type-I hyaluronidase were purchased from Sigma-Aldrich (St Louis, MO, USA). FACS lysing solution and Cytofix/Cytoperm solution were obtained from BD Pharmingen (San Jose, CA, USA). A rabbit anti-human LRG1 antibody, a FITC-conjugated mouse anti-rabbit IgG antibody, and a PE-conjugated mouse anti-rabbit IgG antibody were purchased from LifeSpan BioSciences (Seattle, WA, USA). PerCP-conjugated mouse anti-human CD4, PE/Cy7-conjugated mouse anti-human CD8, APC/CY7-conjugated mouse anti-human CD14, APC-conjugated mouse anti-human CD19, APC/Cy7-conjugated mouse anti-human CD16, PE/Cy7-conjugated mouse anti-human CD123, PerCP-conjugated mouse anti-human HLA-DR, PE/Cy7-conjugated mouse anti-human CD34, PerCP-conjugated mouse anti-human FcεR1, PE-conjugated mouse anti-human CD117, FITC-conjugated mouse anti-human CD90, APC-conjugated mouse anti-human TGFBR2, and PE-conjugated mouse anti-human TGFBR2 antibodies were purchased from BioLegend (San Diego, CA, USA). Allergens for skin prick tests were supplied by ALK-Abelló, Inc. (Denmark). Human LRG1, TGFBR2, and tryptase ELISA kits were purchased from R&D Systems (Minneapolis, MN). Most general-purpose chemicals such as salts and buffer components were of analytical grade.