Use of the CODEX protocol to stain cellularly dense human lymphoid tissues with a panel of 46 antibodies (n = 1 CODEX multicycle imaging of each tissue with stated antibody panel: 3 tonsils, each from a different donor, 1 spleen from another donor, and 1 lymph node from another donor). (A) The 46‐antibody panel contains antibodies to key adaptive and innate immune, functional, and stromal, and epithelial markers. (B) Overview images of five lymphoid tissue samples with Cytokeratin (blue), CD19 (red), and CD3 (green) shown. The higher magnification tile image shows tonsil 9338 with CD19 (blue), CD57 (grey), CD8 (green), Ki67 (yellow), Collagen IV (magenta), CD4 (red), and Cytokeratin (cyan). (C) Representative images of a zoomed in tile from tonsil 9338 of all markers and Hoechst staining. Scale bars: 100 μm, 20× magnification.