The complement system in teleost fish: Progress of post-homolog-hunting researches

Complement C5a acts as molecular adjuvant in fish by enhancing antibody response to soluble antigen

“…In many fish species, such as rainbow trout, carp (Cyprinus carpio), zebrafish (Danio rerio), medaka (Oryzias latipes), flounder (Paralichthys olivaceus) and catfish (Ictalurus punctatus), complement components were found conserved [42,43]. However, many complement components, including C2, C3, C4 and C5, have multiple isoforms in fish, and different function for these isoforms has been suggested [25,44].…”

Feeding common carp Cyprinus carpio with β-glucan supplemented diet stimulates C-reactive protein and complement immune acute phase responses following PAMPs injection

“…This might be explained by the polymorphic complexity of the complement system in common carp [34,41] and the choice of the primers used [33] which may not have detected the appropriate gene isoforms responsible for the Bf/C2 and C3 proteins expression. The results however do suggest that based on the gene expression, the lectin and classical complement pathways (c1rs and masp2 respectively) may not have been actively stimulated by oral administration of b-glucan, except in the mid-gut tissue where masp2 was up-regulated.…”

“…To a greater extent, mRNA level of a given gene may not systematically reflect protein level and activity due to post-transcriptional and transductional regulation mechanisms. In addition, the tetraploidy nature of the common carp and the preservation of multiple isoforms of innate immune proteins in fish [41,56], makes the selection of the genes to analyse harder.…”

A Review of Immune System Components, Cytokines, and Immunostimulants in Cultured Finfish Species

“…and C5 convertases are used to enhance the progression through the cascade and cleave new molecular subsets [28]. Ultimately, the complement exerts its' ability to extinguish pathogens by lysis with the MAC or targeting the cells for further removal via opsonization [14].…”