In general, higher vertebrates such as mouse and rat are used as model organisms in immunological research. Nevertheless, the zebrafish and Medaka model systems offer some advantages over higher vertebrates which can also be exploited to answer questions in immunological science. Zebrafish and Medaka are extraordinarily fecund. This opens up the possibility to carry out genetic studies such as mutagenesis screens. Such screens are also performed to identify genes and pathways which are important for the development and function of the immune system. Sequencing of fish genomes and analysis of gene functions have shown that there are less differences between fish and humans than expected. This implies that results from mutagenesis screens in fish can be transferred to and used for studies on hereditary diseases affecting the human immune system.
The rapid extracorporal development and the transparency of zebrafish and Medaka embryos is another advantage of these model organisms, making them superior to higher vertebrates for certain experimental approaches. For example, transgenic lines make it possible to monitor the development of the embryo and its organs in vivo on a cellular level. Furthermore, the fish embryo is easily accessible allowing manipulation of and interference with developmental processes.
The fish facility at the Max Planck Institute of Immunobiology and Epigenetics was opened in 2007. It houses zebrafish (Danio rerio) and Medaka (Oryzias latipes). Each room is equipped with an independent water treatment unit. Access to the facility is restricted and automatically recorded; technical parameters of the entire facility are remotely controlled. A separate quarantine room provides opportunity for short term experiments without compromising the high hygienic standards of the main facility. Currently, about 50 different lines carrying ENU-induced mutations affecting different developmental processes and several transgenic lines are kept in the system. Wild-type strains are maintained for breeding experiments as well as for general egg and embryo supply.