Figure 1.

Representative images of each granuloma category (1–6) for both rhesus and cynomolgus macaques. HE. Category 1 (A, B) granulomas are small, unorganised, diffuse foci of mixed inflammatory cells but lack a peripheral cuff of lymphocytes. Category 2 (C, D) granulomas consist of similar cells types as category 1 lesions but are larger and more defined, becoming circular in shape. Category 3 (E, F) granulomas are the same as category 2 but with the addition of focal necrosis. Category 4 (G, H) granulomas are an organised structure that are well circumscribed and consist mainly of macrophages and evidence of a few peripheral lymphocytes. Category 4 lesions that exhibit necrotic foci with degenerate neutrophils are classed as category 5 (I, J). Classic, largely well-demarcated granulomas with central, caseous necrosis and a variable rim of lymphocytes are classified as category 6 (K, L). Bars in micrographs (A, B)= 100µm, (C–J) = 250µm, (K, L) = 1000µm.