Immunofluorescent Staining of IL-20/22 Receptors

OCs were grown from RA SFMCs on sterile glass slides in 24-well cell culture plates and stained for confocal microscopy as previously described [35 (link)]. Briefly, cells were fixed with 4 % paraformaldehyde for 10 minutes at RT. Non-specific binding was blocked by incubating in PBS with 0.5 % BSA and 5 % goat serum for 30 minutes at RT. Cells were stained with either anti-IL-20R1 IgG1 (173714; R&D Systems) or anti-IL-22R1 IgG1 (305405; R&D Systems) in combination with goat anti-mouse IgG1 Alexa 488 (Invitrogen). Cells were co-stained with anti-TRAP IgG2b in combination with goat anti-mouse IgG2b Alexa 647 (Invitrogen). Isotypes served as negative controls. Glass slides were placed in Prolong Gold Antifade Mountant with DAPI (Life Technologies) and allowed to dry overnight. All micrographs were collected using a Zeiss LSM-710 confocal microscope.