FIGURE 2

FIGURE 2

Structure and cellular composition of granulomas. Early innate M. marinum granulomas, as described in zebrafish embryos, are composed of compact, organized aggregates of macrophages that have either transformed into epithelioid cells with tightly interdigitated cell membranes or have fused to become multinucleated giant cells. Bacilli are found both extracellularly in the necrotic core of the granuloma and intracellularly within phagocytes (A). The characteristic mature tuberculous granuloma is populated by many other cell types such as neutrophils, dendritic cells, B and T cells, natural killer cells, and foam cells, which are macrophages with accumulated lipids (B) (created with biorender.com).