Table 1.
Development of thymus and T cells in fish.
| Species, temperature in parenthesis | Formation of thymic rudiment | Appearance of small lymphocytes | Expression of T cell relevant genes in thymus | Differentiation of Cortex/Medulla | References |
|---|---|---|---|---|---|
| Rainbow trout(14°C) (8–15°C) |
5 days pre-hatch (stage 28 *1) | 3 dph (stage 32 *1) |
cd8α: 1wpf tcrβ: 2 wpf |
[28] [31] |
|
| Carp (22–25°C) Hatching occurs 2–3.5 days after fertilization | 2 dph (stage 27–31 *2) 3 dpf |
8 dph (stage 35–36 *2) 4 dpf (WCL9+ve cells) |
rag1: 4 dpf |
4 wpf 1 wpf (rag1/WCL9) |
[32] [22] [33] |
| Zebrafish (27–28.5 °C) Hatching occurs 3 days after fertilization | 54–60 hpf | 7 dpf |
ikaros, gata3, rag1, lck: 72 hpf 3.5dpf tcrα & rag1: 4 dpf |
6 wph (rag1 expression at peripheral thymus) | [34] [35] [25] |
| Sea bass (15–16 °C) Hatching occurs 2 days after fertilization | 27 dph | 30 dph (DLT15+ve cells) |
tcrβ: 25 dph cd4, cd8α: 51 dph |
75 dph (cd4 expression) |
[36] [38,39] |
| Rock fish (20 °C) Birth occurs 4 days after hatching | 10–12 dph | 21 dph | ND | 40 dph | [29] |
hpf: hours post-fertilization; dpf: days post-fertilization; dph: days post-hatch; wpf: weeks post-fertilization; wph: weeks post-hatch. *1: Developmental stages for rainbow trout were designated according to Vernier (1969). *2: Developmental stages for carp were designated according to Balinsky (1948).