Purification and partial characterisation of striped trumpeter (Latris lineata) systemic immunoglobulin for the purpose of polyclonal anti-serum production

The striped trumpeter (Latris lineata) has been identified as a new species for diversification of the Tasmanian finfish culture industry. It is a deep water species with an unusually long, oceanic post-larval developmental stage and therefore, has not been easy to culture. Recent breakthroughs in the hatchery phase of culture have enabled the first sea cage grow-out trials. As the culture of striped trumpeter moves towards commercial-scale grow-out, knowledge of the immune system as it relates to disease resistance and vaccination is becoming more important. This study began at the basic level of immunoglobulin (Ig) characterisation and then moved onto the creation of anti-serum, which was used as an immunological tool to investigate the onset of the antibody response in the striped trumpeter. Similar to many other teleost species, striped trumpeter Ig is composed of a light chain of Mr 28 ± 3 kDa and a dominant heavy chain of Mr 86 ± 7 kDa. As seen in many other species of teleosts, these heavy and light chains form a tetrameric molecule weighing approximately 926 kDa. Purified striped trumpeter Ig was used to create polyclonal anti-serum directed against the light chain. The anti-serum was then used to investigate the ontogeny of the antibody response. Using Western blot analysis, Ig could not be detected until larvae were 225 days post-hatch (dph). This is later in terms of days post-hatch than other fish examined and could affect future husbandry and vaccination practices for this species.