Functional characterisation of a macrophage-activating factor produced by leucocytes of gilthead seabream ( L.)

In vitro interactions between rainbow trout (Oncorhynchus mykiss) macrophages and Vibrio anguillarum serogroup O2a

“…V. anguillarum serogroup O2a was killed by rainbow trout macrophages to some degree, but opsonisation did not enhance the bactericidal activity of the macrophages. Bactericidal activity of phagocytes has been demonstrated by others against V. anguillarum serogroup O1 in gilthead seabream leucocytes (Sparus aurata L.) (Mulero & Meseguer, 1998) and against V. anguillarum serogroup O2 in Fundulus heteroclitus phagocytes (Roszell & Anderson, 1996), but neither of these studies considered the influence of antibodies. The present study indicates that killing of V. anguillarum serogroup O2a was optimal at a moi of 0·08 (i.e.…”

“…Surprisingly, in the present study, activation of the macrophages with LPS and TNF-did not increase the macrophage killing index or the moi at which killing of V. anguillarum serogroup O2a occurred, contrary to what has been reported for other pathogens (Campos-Pérez et al, 1997). An alternative way of activating macrophages is by use of macrophage-activation factors (MAF) released by leucocytes stimulated with a mitogen and PMA (Mulero & Meseguer, 1998). Activation of rainbow trout macrophages with MAF may improve the killing of V. anguillarum serogroup O2a, as Mulero & Meseguer (1998) showed that the killing of a V. anguillarum serogroup O1 strain was increased after activation of gilthead seabream macrophages with MAF.…”

“…An alternative way of activating macrophages is by use of macrophage-activation factors (MAF) released by leucocytes stimulated with a mitogen and PMA (Mulero & Meseguer, 1998). Activation of rainbow trout macrophages with MAF may improve the killing of V. anguillarum serogroup O2a, as Mulero & Meseguer (1998) showed that the killing of a V. anguillarum serogroup O1 strain was increased after activation of gilthead seabream macrophages with MAF. The conventional macrophage bactericidal activity method for fish cells (Graham et al, 1988) was modified as an essential point in this study.…”

“…Stave et al (1985), Sakai et al (1993) and Bramble & Anderson (1998) showed that live V. anguillarum (of serogroup O2, unspecified serogroup and a non-pathogenic serogroup O2 strain, respectively), induced a chemiluminescence (CL) response in macrophages of the teleost fish, striped bass (Stave et al, 1985;Bramble & Anderson, 1998) and rainbow trout (Sakai et al, 1993), using luminol to detect H 2 O 2 production. There are very few studies of the bactericidal ability of fish macrophages towards V. anguillarum, though both O1 and O2 strains have been reported to be killed (Mulero & Meseguer (1998) using gilthead seabream macrophages, and Roszell & Anderson (1996) using Fundulus heteroclitus macrophages, respectively). There is no information available on the interaction of salmonid macrophages with V. anguillarum or the role of antibody in opsonisation.…”

Molecular cloning, gene organization and expression of rainbow trout (Oncorhynchus mykiss) inducible nitric oxide synthase (iNOS) gene

“…The inability to clone the rainbow trout iNOS transcript may relate to differences in expression level in comparison with other teleost fish groups. Thus in the superorder Ostariophysi, including goldfish [4,5], carp [3] and catfish [6,7], and in the superorder Acanthopterygii, including turbot [8,9] and seabream [10], leucocytes can be readily stimulated to produce nitric oxide. This is not the case with trout (superorder Protacanthopterygii), where detection of the iNOS transcript has required nested PCR following stimulation with equivalent stimuli such as lipopolysaccharide or live bacteria [1,11].…”