Immunohistochemical staining of formalin-fixed, paraffin-embedded (FFPE) cell lines and select tissues with anti-PD-L2 antibody. Staining of A) Untransfected murine pre-B cell line, 300.19, B) Pre-B line stably expressing human PD-L1, C) Pre-B line stably expressing human PD-L2, D) Diffuse large B-cell lymphoma cell line SU-DHL-4, E) Mediastinal large B-cell lymphoma cell line Karpas 1106P, F) Hodgkin lymphoma line HDLM-2, G) Lymph node showing a reactive germinal center (400x), H) High power image of a reactive germinal center (1000x), I) Macrophages, including a multi-nucleated giant cell, associated with necrotic tissue. The average PDCD1LG2 copy number for each human cell line is indicated in the bottom right corner of each image. All images 1000x original magnification unless indicated.