Confocal image of green-fluorescent macrophage aggregate surrounding red-fluorescent Mycobacterium marinum, located in the retinal parenchyma.

The mycobacteria are intracellular within macrophages (arrows) as well as extracellular (arrowheads). Scale bar, 50 μm.

Anatomical localization of intraocular granuloma after M. marinum infection.

(A) Schematic representation showing localization of granulomas near the retinal vasculature (arrowhead), and in retinal pigment epithelium-choroid complex (dotted circle). (B) Localization of intraocular granulomas (within dotted regions); in the outer eye of zebrafish larvae corresponding to the retinal pigment epithelium-choroid complex, and in the choroid in human ocular TB. (C) Localization of perivascular infection (arrowheads); as seen as bacterial aggregates in close association of blood vessels in zebrafish, and retinal periphlebitis associated with focal chorioretinitis overlying the blood vessel in human ocular TB. (B-C) Confocal images of ocular infection in Tg(mpeg:YFP) and Tg(kdrl:dsRed2) zebrafish, and fundus photographs of human ocular TB. Scale bars, 25 μm and 750 μm, respectively.

Recruitment of peripheral blood monocytes in granuloma formation.

(A-C) Granuloma formation in Tg(mfap4:tdTomato) fish with red-fluorescent macrophages and infected with green-fluorescent M. marinum. Hoechst-positive (blue-fluorescent) peripheral blood monocytes which have been recruited into the infected eye are seen within the granuloma (inset and panel B) and in contact with a single infected macrophage (inset and panel C). The retinal microglia are incorporated into the granuloma and also dispersed uniformly within the ocular tissues. Scale bars, 30 μm.