CELLULAR-RESPONSES OF LEUKOCYTES ISOLATED FROM THE GUT OF RAINBOW-TROUT, ONCORHYNCHUS-MYKISS (WALBAUM)

Leucocytes were isolated from the gut of rainbow trout by collagenase digestion. They were shown to be capable of producing a chemoattractant(s) for head kidney leucocytes and a macrophage activating factor, following stimulation with calcium ionophore and T-cell mitogens, respectively. They also included low but significant numbers of phagocytes, as determined by phagocytosis of fluorescent latex microspheres and oxygen free radical production. However, migration of isolated gut cells in response to head kidney chemoattractants was lacking. The significance of these results in relation to mucosal immunity is discussed.