Angiopoietin-4 in Human Lung. Angiopoietin-4 was detected in immersion fixed paraffin-embedded sections of human lung using 10 µg/mL Goat Anti-Human Angiopoietin-4 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF964) overnight at 4 °C. Before incubation with the primary antibody tissue was subjected to heat-induced epitope retrieval using Antigen Retrieval Reagent-Basic (Catalog # CTS013). Tissue was stained with the Anti-Goat HRP-DAB Cell & Tissue Staining Kit (brown; Catalog # CTS008) and counterstained with hematoxylin (blue). Lower panel shows a lack of labeling if primary antibodies are omitted and tissue is stained only with secondary antibody followed by incubation with detection reagents. View our protocol for Chromogenic IHC Staining of Paraffin-embedded Tissue Sections.