The laboratory for fish immunology deals with the development of tools and methods for the characterization of the cellular immune response in fish. Well established and novel immunological methods are used for the characterization of the naive (including ontogeny studies) and responding immune systems (after viral and bacterial infections). The laboratory has a long tradition in cell-mediated cytotoxicity.
Cell-mediated immune responses in fish
In contrast to fish humoral immune responses, virus-specific cell-mediated reactions are not well understood. Since the induction of an antibody response does not always correlate with an efficient protection cell-mediated immune responses may play an important role.
Virus infections are controlled by innate and adaptive cell-mediated cytotoxicity (CMC) in mammals. The cellular part of the innate immune system is represented by non-specific cytotoxic cells (NCC) and NK (natural killer) cells. These cells are able to kill xenogenic, allogenic and virus infected cells. However, virus infected cells are largely controlled by adaptive CMC, too. During this, virus-infected cells present MHC class I bound viral peptides on their surface to the T cell receptor (TCR) of CD8+ cytotoxic T cells (CTLs) [figure]
Sequence homologies between the piscine and mammalian MHC class I, TCR and its co-receptor CD8, suggest that antigen presentation in fish is MHC class I restricted like in mammals. While the expression of most immune-related molecules can only be indirectly determined through mRNA expression we have developed monoclonal antibodies to MHC class I and CD8alpha.
In most fish species, cytotoxicity has not been studied due to the lack of suitable methods and tools. In collaboration with Japanese and French partners we have established cytotoxicity assays using clonal rainbow trout and infected MHC class I matched target cells. For the generation of cytotoxic effector cells clonal rainbow trout are infected or are immunized by DNA encoding immunogenic viral proteins. Population-specific antibodies are used to enrich cytotoxic cells, and real time RT-PCR is used to determine the expression of immune-related genes.
Projects (recent and running)
- The Danish Council for Strategic Research: Targeted Disease Prophylaxis in Marine Fish Farming (ProFish) – Gezielte Prophylaxe von Fischkrankheiten in der marinen Aquakultur, 2012-2016
- The Norwegian Research Council: Protection against intracellular pathogens: T-cell based immunity and vaccines (T-mmune) – Immunschutz gegen intrazelluläre Erreger – T-Zell-basierte Immunität und Vakzination, 2012-2014
- EU, TargetFish, Targeted disease prophylaxis in European fish farming, 2012-2017
- German Research Council, Harnessing interleukin 2 (IL-2) family power in fish; study of rainbow trout IL-2, IL-15, IL-15L and IL-15Ralpha, 2017-2019
- EU, VetBioNet, Veterinary Biocontained facility Network for excellence in animal infectiology research and experimentation, 2017-2021
Overview of Methods
- in-vitro assays for cell-mediated cytotoxicity
- cell separation and cytology
- immunohistochemistry
- flow cytometry and cell sorting
- confocal laser scanning microscopy
- real-time RT-PCR
- sequencing
- production of monoclonal antibodies
- production of recombinant proteins
- infection trials with fish up to biosecurity level L3