TNF and infection: In addition to phagocyte recruitment, zebrafish also allow for the assessment of phagocyte activation and recent work in both the swimbladder and yolk models of infection demonstrate that the major cell type expressing TNF-α at the site of infection is the macrophage, whose presence there drives large increases in TNF-α expression host-wide (A.K.S., L.S.A., and R.T.W., unpublished).