Phylogeny and expression analysis of C-reactive protein (CRP) and serum amyloid-P (SAP) like genes reveal two distinct groups in fish

P. T. Lee, S Bird, J Zou, S. A. M. Martin* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)
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The acute phase response (APR) is an early innate immune function that is initiated by inflammatory signals, leading to the release of acute phase proteins to the bloodstream to re-establish homeostasis following microbial infection. In this study we analysed the Atlantic salmon (Salmo salar) whole-genome database and identified five C-reactive protein (CRP)/serum amyloid P component (SAP) like molecules namely CRP/SAP-1a, CRP/SAP-1b, CRP/SAP-1c, CRP/SAP-2 and CRP/SAP-3. These CRP/SAP genes formed two distinct sub-families, a universal group (group I) present in all vertebrates and a fish/amphibian specific group (group II). Salmon CRP/SAP-1a, CRP/SAP-1b and CRP/SAP-1c and CRP/SAP-2 belong to the group I family whilst salmon CRP/SAP-3 is a member of group II. Gene expression analysis showed that the salmon CRP/SAP-1a as well as serum amyloid A-5 (SAA-5), one of the major acute phase proteins, were significantly up-regulated by recombinant cytokines (rIL-1β and rIFNγ) in primary head kidney cells whilst the other four CRP/SAPs remained refractory. Furthermore, SAA-5 was produced as the main acute phase protein (APP) in Atlantic salmon challenged with Aeromonas salmonicida (aroA(-) strain) whilst salmon CRP/SAPs remained unaltered. Overall, these data illustrate the potential different functions of expanded salmon CRP/SAPs to their mammalian homologues.
Original languageEnglish
Pages (from-to)42-51
Number of pages10
JournalFish & Shellfish Immunology
Early online date20 Mar 2017
Publication statusPublished - Jun 2017

Bibliographical note

This work was funded by British Society of Animal Science/Genesis Faraday to both SAM and SB Immune control of energy reallocation in fish and a BBSRC Research Experience Placements (2010).


  • acute phase protein
  • C-reactive protein
  • serum amyloid-P
  • Atlantic salmon
  • innate immunity
  • gene expression


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