Figure 1

Figure 1

Neutrophils are found only in the olfactory organs of the adult brain. (A) Wholemount brain of Tg(omp:RFP);Tg(mpx:GFP) adult: neutrophils (green) are only present in the OO (OE/EN); Tel: telencephalon; pi: pineal. Scale bars A, B = 200 μm. (B) OO (from A) contains a large population of neutrophils (green, n=487 neutrophils). omp:RFP⁺ OSNs are located only in sensory epithelia (ss, red) not in non-sensory epithelia (ns). ON: olfactory nerve. (C) Neutrophils with a rounded shape, (nt1, arrow: circularity index 0.7 or greater) and amoeboid shape (nt2, arrow: circularity index of 0.4-0.6; F) were observed in the LOE. (D) Neutrophils with an amoeboid shape (nt2, arrow) were located throughout the OE and EN. (D1) Sustentacular-like cells (D1), circularity index 0.2, lie at ns-ss epithelia interface (see Figure 2). (E) Total number of neutrophils in the OO. The non-sensory (ns) tissues (respiratory epithelia + NE, blue) have more neutrophils than sensory epithelia (ss, red), n= 3 OE from 3 different fish. (E) **indicates significant statistical differences between means with a p-value < 0.002, paired t-test.. (F) Frequency distribution of nt1 and nt2 cells (n= 53 neutrophils from brain shown in C). (G) Maximal projection of whole mount Tg(mpx:GFP) adult OE: Neutrophils (green); autofluorescence (gray). (H) Neutrophils (from G) were color-coded based on (H) Z-stack depth. Total depth= 550μm. Scale bars A, B = 200 μm; C = 60 μm; D, D1 = 20 μm; G, H =100 μm. (A, B) 9 brains imaged; (C, D) 6 brains sectioned.