Association of hCLCA1 with mucin granules within NHBE cells. Ultra-thin sections of NHBE cells cultured on Transwell® inserts were evaluated by ultrastructural immunohistochemistry to elucidate the subcellular distribution of hCLCA1. Tissue sections were incubated with primary rabbit anti-mclca3 antibody followed by incubation with 12 nm gold-labeled goat anti-rabbit secondary antibody. CLCA1 appears to be localized in proximity to the mucin granules (arrows, B). Negative control using rabbit IgG as the primary antibody; little if any background staining is observed (A). Magnification is at 70Kx.