Activation of rainbow trout macrophages

Rainbow trout peritoneal macrophages were stimulated in vitro using Concanavalin A (Con A) and in vivo using formalin-killed Aeromonas salmonicida in Freund's incomplete adjuvant (FIA). Whether these cells had been activated was determined by the measurements of oxygen anions (NBT reduction), H₂O₂ production (oxidation of phenol red), RNA synthesis (³H-uridine incorporation), acid phosphatase activity and bactericidal activity.
In vitro -stimulated macrophages showed an increased NBT reduction and ³H-uridine incorporation over a range of Con A concentrations, compared with untreated control macrophages, but no detectable increases in H₂O₂ production or bactericidal activity were observed. On the other hand, in vivo -stimulated peritoneal cells showed increases in all the assays compared with FIA-elicited control cells, and were considered to have been activated.