Effect of temperature on macrophage activation and the production of macrophage activating factor by rainbow trout (Oncorhynchus mykiss) leucocytes

L. J. Hardie, T. C. Fletcher, C. J. Secombes*

*Corresponding author for this work

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79 Citations (Scopus)


Production of macrophage activating factor (MAF) by rainbow trout leucocytes has been shown to be temperature dependent in vivo and in vitro. Cells from fish held at 14°C and stimulated to produce MAF immediately after isolation were capable of secreting MAF down to 6°C (the lowest temperature tested). However, after 48 h at 6°C, these leucocytes show impaired MAF secretion. Acclimation of fish to low temperatures (7°C) did not recover the inhibitory effects of low in vitro temperatures on MAF production, but if these leucocytes were preincubated at 10 or 18°C for 48 h, MAF was produced from these cells. Interestingly, macrophages isolated from fish kept at 7 or 14°C and cultured at low temperatures (6°C) were responsive to MAF-containing supernatants, and showed a higher relative increase in respiratory burst activity compared with their counterparts cultured at 10 and 18°C. Such observations clearly demonstrate that a major impairment of bactericidal activity at low temperatures resides within the specific immune compartment of fish. The implications for fish health are discussed.

Original languageEnglish
Pages (from-to)57-66
Number of pages10
JournalDevelopmental and Comparative Immunology
Issue number1
Publication statusPublished - Jan 1994



  • (MAF)
  • Macrophage activating factor
  • Macrophages
  • Rainbow trout
  • Respiratory burst
  • Temperature

ASJC Scopus subject areas

  • Immunology
  • Developmental Biology

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