REVIEWImmunology and zebrafish: Spawning new models of human disease
Introduction
In the late 1960s, George Streisinger embarked upon a quest to develop a vertebrate model organism that would not only be amenable to forward genetics but would also be able to effectively model human diseases, a characteristic mostly lacking in invertebrates [1]. Perhaps because of his history as a life-long fish-hobbyist, Streisinger, auditioned several species of fish for the role, and eventually settled on the zebrafish (Danio rerio), a small tropical fish popular in aquariums. His goal was to develop protocols designed to rapidly identify germ-line recessive mutations, and his first success was seen in the early 1970s when he was able to create haploid embryos [1]. He later worked out procedures to produce homozygous diploid clones of zebrafish, the details of which were outlined in his landmark paper published in the 1981 issue of Nature [2].
The zebrafish has favorable characteristics that make it an ideal organism for the study of vertebrate developmental biology (see below), and in 1993 two large-scale phenotype-driven genetic screens (Tübingen and Boston) were undertaken to identify embryonic lethal mutations. Rapidly, an unprecedented number of developmental genes and pathways were uncovered in a vertebrate model, and as the scientific publications mounted, the status of the zebrafish as a bona fide research model was cemented.
Over the last decade, the zebrafish has been adopted into a variety of research arenas beyond developmental biology, and the number of new zebrafish models of human disease continues to grow. This is certainly the case in the fields of infection and immunology as evidenced by the recent workshop held in Leiden, Netherlands, under the auspices of EMBO and entitled, “Model systems for infectious disease and cancer in zebrafish.” A variety of new and more established models were presented, shedding new light on zebrafish immune function and cancer, as well as human disease. The success of this inaugural meeting resulted in its establishment as a satellite workshop in conjunction with the biannual conferences of the European zebrafish community.
In this review, we begin with a summary of the unique characteristics of the zebrafish as a model organism. We then provide an overview of the zebrafish immune system, and its remarkable similarity to its mammalian counterparts. Finally, we detail the various models that have been created using zebrafish to study both innate and adaptive immunity as well as immune-cell-derived malignancies.
Section snippets
Zebrafish model advantages and disadvantages
The zebrafish has many advantages when compared to other animal models. Among animals with a fully developed adaptive and innate immune system, the zebrafish is one of the smallest (⩽5 cm), allowing large numbers of fish to be housed in a relatively small space. They are prolific, with a given pair able to produce 200–300 new progeny each week. Fertilization of eggs and the subsequent development of embryos occur ex vivo, facilitating visual tracking of maturation processes. Furthermore, embryos
Mechanisms for disease model development
Most zebrafish disease models were created through forward genetics. The zebrafish was first established as a valid model organism by developmental biologists who uncovered large numbers of genes and pathways through phenotype-driven screens (reviewed in [10], [11], [12]). Because of its size and fecundity, large screens can be carried out speedily and at relatively low cost. Furthermore, point mutations can be easily introduced into the germline by ethyl-nitroso-urea (ENU). Other methods that
Overview of the zebrafish immune system
In general, the zebrafish immune system has proven to be remarkably similar to that of humans (reviewed in [23]). The evolution of the adaptive immune system coincided with the emergence of jawed vertebrates, far in advance of the divergence of fishes from other vertebrates [24], [25]. Thus, the adaptive and innate branches of the immune system are remarkably conserved across jawed fishes (teleosts) and other vertebrates, including mammals. Studies of hematopoiesis have revealed that most if
Models of infection and innate immunity
The zebrafish model has proven to be useful in characterizing three aspects of the innate immune system: the acute-phase response to infection, the interaction of host and pathogen (often making use of fluorescently labeled bacteria), and the chemotactic response to injury. Current progress in these three areas is detailed below. The combination of translucent fish and fluorescent labeling of immune cells and/or infectious organisms allows for the real-time assessment of the vertebrate innate
Adaptive immunity models
Regarding the adaptive immune response, there are at least three categories of disease models that can be envisioned in zebrafish: autoimmunity, lymphoproliferative disease, and immunodeficiency. As of yet, there are no good models for autoimmunity in the zebrafish; however, there are at least three arguments that autoimmunity should occur in the zebrafish. Firstly, the manner in which T and B cells undergo antigen receptor rearrangements in zebrafish is very similar to that of humans. Thus, it
Immune system malignancies
As introduced above, there are several models of clonal lymphoproliferation in the zebrafish. All published models make use of the overproduction of known oncogenes driven by endogenous promoters in transgenic fish. Two oncogenes have been used to drive T cell and one for B cell malignancies.
T cell acute lymphoblastic leukemia (T-ALL) was first induced in transgenic zebrafish carrying the mouse c-myc gene under control of the zebrafish rag2 promoter. To facilitate visualization of the tumor
A novel screen to identify new zebrafish models of immune dysregulation
As noted above, transgenic zebrafish containing fluorochrome-expressing constructs driven by lineage-specific promoters allow for in vivo cell tracking using fluorescent microscopy. One such transgenic is the lck:eGFP line wherein green fluorescence is driven by the T cell-specific tyrosine kinase, p56lck. In these animals, immature and mature T cells fluoresce green, and this transgenic line has facilitated characterization of T cell development in the zebrafish. For example, immature T cells
Conclusion
The zebrafish has emerged as a powerful new vertebrate model of human disease. Although its power for gene discovery was first utilized by developmental biologists, this small fish is now found in laboratories crossing multiple areas of study, including immunology. As initially envisioned by George Streisinger 40 years ago, the zebrafish has proven to present a unique combination of characteristics facilitating rapid gene discovery, and the ability to model human disease. This is certainly true
References (105)
- et al.
Convergence of distinct pathways to heart patterning revealed by the small molecule concentramide and the mutation heart-and-soul
Curr Biol
(2001) - et al.
Discovery and use of small molecules for probing biological processes in zebrafish
Methods Cell Biol
(2004) - et al.
Mutagenesis strategies in zebrafish for identifying genes involved in development and disease
Trends Genet
(2006) - et al.
Target-selected gene inactivation in zebrafish
Methods Cell Biol
(2004) Speculations on the origin of the vertebrate immune system
Immunol Lett
(2004)Cellular dissection of zebrafish hematopoiesis
Methods Cell Biol
(2004)- et al.
Tracing hematopoietic precursor migration to successive hematopoietic organs during zebrafish development
Immunity
(2006) - et al.
The cloche and spadetail genes differentially affect hematopoiesis and vasculogenesis
Dev Biol
(1998) - et al.
Development of the zebrafish lymphatic system requires vegfc signaling
Curr Biol
(2006) - et al.
Zebrafish as an immunological model system
Microbes Infect
(2002)
Lessons from transgenic zebrafish expressing the green fluorescent protein (GFP) in the myeloid lineage
Methods Cell Biol
Myelopoiesis in the zebrafish, Danio rerio
Blood
Morphologic and functional characterization of granulocytes and macrophages in embryonic and adult zebrafish
Blood
Development of a respiratory burst assay using zebrafish kidneys and embryos
J Immunol Methods
A zebrafish orthologue (whnb) of the mouse nude gene is expressed in the epithelial compartment of the embryonic thymic rudiment
Mech Dev
T cells and the thymus in developing zebrafish
Dev Comp Immunol
Development and maturation of the immune system in zebrafish, Danio rerio: a gene expression profiling, in situ hybridization and immunological study
Dev Comp Immunol
Structural characteristics of zebrafish orthologs of adaptor molecules that associate with transmembrane immune receptors
Gene
Ontogeny of the immune system of fish
Fish Shellfish Immunol
The use of zebrafish to understand immunity
Immunity
Expression analysis of the toll-like receptor and tir domain adaptor families of zebrafish
Mol Immunol
Toll-like receptor gene family and tir-domain adapters in Danio rerio
Mol Immunol
Acute-phase response in zebrafish upon Aeromonas salmonicida and Staphylococcus aureus infection: striking similarities and obvious differences with mammals
Mol Immunol
Pathogenesis and inflammatory response to Edwardsiella tarda infection in the zebrafish
Dev Comp Immunol
Real-time visualization of mycobacterium-macrophage interactions leading to initiation of granuloma formation in zebrafish embryos
Immunity
Visualisation of zebrafish infection by GFP-labelled Vibrio anguillarum
Microb Pathog
Zebrafish as a model host for streptococcal pathogenesis
Acta Trop
New models for the study of mycobacterium–host interactions
Curr Opin Immunol
Effects of infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus infection on hematopoietic precursors of the zebrafish
Blood Cells Mol Dis
Zebrafish (Danio rerio) as a model for the study of vaccination against viral haemorrhagic septicemia virus (vhsv)
Vaccine
The interferon response is involved in nervous necrosis virus acute and persistent infection in zebrafish infection model
Mol Immunol
A star with stripes: zebrafish as an infection model
Trends Microbiol
A transgenic zebrafish model of neutrophilic inflammation
Blood
Macrophage activation during experimental allergic orchitis in rainbow trout (Salmo gairdneri)
Dev Comp Immunol
Mutations affecting thymus organogenesis in medaka, Oryzias latipes
Mech Dev
The endoderm plays an important role in patterning the segmented pharyngeal region in zebrafish (Danio rerio)
Dev Biol
Tbx1 is responsible for cardiovascular defects in velo-cardio-facial/DiGeorge syndrome
Cell
Headwaters of the zebrafish—emergence of a new model vertebrate
Nat Rev Genet
Production of clones of homozygous diploid zebra fish (Brachydanio rerio)
Nature
Chemical suppression of a genetic mutation in a zebrafish model of aortic coarctation
Nat Biotechnol
In vivo drug discovery in the zebrafish
Nat Rev Drug Discov
Prostaglandin e2 regulates vertebrate haematopoietic stem cell homeostasis
Nature
The zebrafish genome
Methods Cell Biol
Genetic dissection of thymus development in mouse and zebrafish
Immunol Rev
The art and design of genetic screens: zebrafish
Nat Rev Genet
A genetic screen for mutations affecting embryogenesis in zebrafish
Development
The identification of genes with unique and essential functions in the development of the zebrafish, Danio rerio
Development
Transposon tools and methods in zebrafish
Dev Dyn
Insertional mutagenesis in zebrafish
Dev Dyn
Genetic dissection of thymus development
Curr Top Microbiol Immunol
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