Maternal transfer of complement components C3-1, C3-3, C3-4, C4, C5, C7, Bf, and Df to offspring in rainbow trout (Oncorhynchus mykiss)

Abstract

Defense mechanisms in developing fish are poorly known but before maturation of lymphoid organs and immunocompetence, innate mechanisms are essential. The complement system represents a major part of innate immunity. Our main objective was to map the presence of complement components early in fish development. Rainbow trout eggs, embryos, and hatchlings were assayed for the onset and duration of C3-1, C3-3, C3-4, C4, C5, C7, factor B, and factor D transcription using real-time reverse transcription-polymerase chain reaction. In general, complement transcript levels increased steadily from day 28 postfertilization to hatch, followed by a decrease during yolk-sac resorption. All the complement proteins studied were found in unfertilized eggs. There was no correlation between the transcript and protein levels throughout the study period. Complement proteins appeared in the liver, kidney, and intestine between day 7 and 35 but not until day 77 in the heart. This study is the first to address the ontogeny of several complement components and represents the first evidence that maternal transfer of complement components, other than C3, occurs in teleost fish.

Deciphering microbial landscapes of fish eggs to mitigate emerging diseases

“…These results indicate that along with established factors influencing disease susceptibility, such as genetic inheritance (broodstock effect), developmental stage of the salmon eggs, environmental and other stress conditions (Hansen and Olafsen, 1999), the microbiota are also a determining factor in health and disease of fish eggs that have an immature adaptive immune system and depend on other defences for protection. In terms of genetic inheritance, components of the complement immune system were shown to be maternally transferred to the eggs for rainbow trout, zebrafish and amphibian eggs (Lovoll et al, 2006;Poorten and Kuhn, 2009;Wang et al, 2009;Walke et al, 2011), and a paternal genetic component contributed to resistance against Saprolegnia in frog eggs (Sagvik et al, 2008). The relative contribution of the genetic inheritance, the fish egg microbiome or their interplay to protect against Saprolegniosis is not clear yet.…”

The influence of parental effects on transcriptomic landscape during early development in brook charr (Salvelinus fontinalis, Mitchill)

“…Maternal effects are mediated by egg components and, later, by yolk sac components such as nutriments, hormones, components of defense mechanisms, maternally contributed mitochondria and maternal mRNAs (Kanaya et al, 1996;Løvoll et al, 2006;Bai et al, 2007;Green, 2008). The maternal mRNA present in the egg influences its quality and, consequently, embryonic development.…”

Expression of complement components coincides with early patterning and organogenesis in Xenopus laevis

“…Because of the central role of the complement system in innate immunity, expression studies of individual components of the complement system have been primarily performed on the backdrop of the development and function of innate immunity (Ellingsen et al, 2005, Gongora et al, 1998, Kato et al, 2004, Lovoll et al, 2007, Lovoll et al, 2006, Mastellos and Lambris, 2002. However, there is evidence suggesting that the function of these molecules is not strictly limited to immunity (Mastellos and Lambris, 2002) (Mastellos et al, 2005).…”