Do fish lymphocytes secrete interferon‐γ?

Abstract

Macrophage activating factor (MAF)-containing supernatants, generated by mitogen (Con A!PMA) stimulation of rainbow trout leucocytes, were found to confer viral resistance (interferon. IFN. activity) on a rainbow trout epithelial cell line challenged with infectious pancreatic necrosis virus. Both the MAF and IFN activities co-eluted by HPLC size exclusion chromatography and showed similar sensitivities to acid (pH 2), temperature (60" C) and trypsin. The mode of induction of this IFN, its acid and temperature sensitivity and its possible MAF activity suggest that fish leucocytes can secrete an IFN-7 like molecule.

Channel catfish reovirus (CRV) inhibits replication of channel catfish herpesvirus (CCV) by two distinct mechanisms:viral interference and induction of an anti-viral factor

“…Furthermore, rapidlyproliferating MLC cultures contain increased numbers of activated natural killer and/or T cells (Stuge et al 1997) and likely synthesize interferon y and a variety of other cytokines. Consistent with these results, Graham & Secombes (1990) found that an interferon y-like activity was secreted by trout leukocytes following mitogen stimulation. However, attempts in our laboratory to detect mRNA encoding type I interferon or tumor necrosis factor (TNF) a in long-term catfish lymphoid cell lines by Northern blot analysis using mammalian probes for TNFa, interferon a, and interferon P or by reverse transcription polymerase chain reaction (RT-PCR) were not successful.…”

“…Although interferon-mediated anti-viral effects are well characterized in mammals (Weissman & Weber 1986, Vilcek & Sen 1996, much less is known about the role they play in lower vertebrates (Yano 1996). Interferon-like activities have been identified in a variety of fish species, but definitive identification based on physiochemical and genetic properties is lacking (Beasley et al 1966, Oie & Loh 1971, De Sena & Rio 1975, Eaton 1990, Graham & Secombes 1990, RogelGaillard et al 1993, Snegaroff 1993, Yano 1996. Furthermore, despite considerable effort, interferon genes from lower vertebrates (i.e.…”

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

“…Similar to their mammalian counterparts, rainbow trout (Oncorhynchus mykiss) macrophages can be activated by a MAF produced by mitogen-stimulated T (surface immunoglobulin negative) cells to enhanced spreading, adherence, respiratory burst and bactericidal activity (Secombes, 1987;Graham & Secombes, 1988, 1990a. The MAF activity present in such supernatants cofractionates with IFN activity, and both activities share the same temperature and pH sensitivities, suggesting that an IFN -like molecule is present (Graham & Secombes, 1990b).…”

Entry and sequential distribution of an aquatic birnavirus in turbot (Scophthalmus maximus)

“…This fact can be attributed to the presence of antiviral substances (neutralizing antibodies, interferon etc.). Interferon production was demonstrated in fish (Graham and Secombes, 1990;Eaton, 1990) and, recently, Dorson et al (1992 detected interferon synthesis when rainbow trout fry were inoculated with Sp strain of IPNV. We have not determined this activity in turbot, which will be a further study to carry out in the future; however, low titres of neutralizing antibodies were detected previously in turbot (Gastric et al, 1987;Novoa et al, 1994).…”