Figure 5

Organization of the zf-GIALT at the gill arch. (Sub-regions 4-5). Representative deconvolved confocal high-resolution images of adult zebrafish gills acquired with a transversal orientation. Images were acquired from 30 μm whole-body cryosections stained with phalloidin (green) and DAPI (blue) and where T/NK cells were labeled with anti-ZAP70 antibody (red hot). The localization of the GIALT sub-regions is illustrated in (G). (A) Lower magnification image illustrating the organization of the GIALT from two gill arches. Cyan arrows point to the numerous T/NK cells close to the basement membrane at the pharyngeal side of the gill arch. Yellow arrowheads highlight scattered T/NK cells within the gill arch, and white arrowheads localize taste buds. (B, C) Images at higher magnification of the zf-GIALT at the pharyngeal aspect of the gill arch. (D–F) Images at higher magnification of the T/NK cell clusters, forming the Amphibranchial Lymphoid Tissue (ALT), located on each side of the gill arches, at the base of filaments. The cyan arrowheads in (E, F) highlight the basement membrane and the reduction of its thickness at the level of the ALT. Images are maximum intensity projections: 2 µm (B–F). Annotations: Aaa, Afferent arch artery; ALT, Amphibranchial Lymphoid Tissue; Bc, Branchial cavity; Bm, Basement membrane; Eaa, Efferent arch artery; Ea, Efferent artery; F, Filament; La, Lamellae; M, Muscles; Mc, Mucous cell; Pvc, Pavement cell; S, Septum and Tb, Taste bud. Scale bars: 50 μm (A) and 20 μm (B–F).