Fish fend off invading germs with an initial response similar to the one found in people

September 24, 2009

Since the human response to infection is highly complex, research to understand how people fight infection is facilitated by studying how similar processes occur in simpler organisms. Zebrafish are becoming an important model for human disease, since they are easily handled, maintained and manipulated and many fundamental processes between zebrafish and humans are conserved. In addition, the small zebrafish embryo is highly amenable to drug screening assays.

The functional similarity between the initial responses of embryo and humans to suggests that the zebrafish embryo may be a valuable model for understanding early immune responses and identifying potential therapeutics for infection or immune mediated disease. However, the initial response of zebrafish to infection and how it compares to the human response is not well understood.

When humans first encounter germs, like viruses or bacteria, the first stage of a two-part inflammatory response is triggered, which is termed the innate immune response. During this early phase, proteins are made around the site of infection to initiate the body's defense system and to recruit circulating immune cells, which begins the inflammatory process. A family of proteins that are critical to instigating the immune response are the interferons (IFN), particularly IFN-γ.

Scientists now report that IFN-γ is also produced in zebrafish when they are exposed to bacteria that cause disease in fish. These studies use developing zebrafish embryos whose response to infection is isolated to the innate immune response. Since the zebrafish embryo only demonstrates innate immunity, it allows for specific study of the effects of IFN-γ on these early events. This study demonstrates that both zebrafish and human IFN-γ proteins function in much the same way, despite having very distinct protein structures. In both zebrafish and humans, IFN-γ triggers the production of an array of proteins that rally the defense mechanisms of the infected cell and activate the immune system. They also found that compromising the ability of the zebrafish embryos to produce IFN-γ impairs the fish's ability to survive infection. Thus, the zebrafish embryo may provide a very simple model to understand the innate .

Interestingly, large quantities of , which would cause septic shock -- a potentially fatal condition -- in humans, do not elicit the same response in zebrafish. This suggests that some key differences between the immune systems of zebrafish and humans may also provide insight into harmful events associated with inflammation.

The characterization of IFN-γ function in zebrafish is presented in the Research Article titled 'The role of gamma interferon in innate inity in the zebrafish embryo', which was written by Dirk Sieger, Cornelia, David Neifer and Maria Leptin at the University of Cologne in Germany and Astrid van der Sar at the VU University Medical Center in Amsterdam in The Netherlands.

More information: The study is published in the November/December 2009 issue of the new research journal, Disease Models & Mechanisms (DMM),, published by The Company of Biologists, a non-profit based in Cambridge, UK.

Source: The Company of Biologists (news : web)

Explore further: Zebrafish: It's not your parents' lab rat

Related Stories

Zebrafish: It's not your parents' lab rat

July 30, 2007

Zebrafish cost about a dollar at the pet store. They grow from eggs to hunting their own food in three days. Adults can lay up to 500 eggs at once… and you have more in common with them than you think.

Zebrafish study shows key enzyme in gut is a peacemaker

December 12, 2007

University of Oregon scientists, using zebrafish to study the gastrointestinal tract, say that an enzyme long assumed to be involved in digestion instead is a detoxifying traffic cop, maintaining a friendly rapport between ...

Zebrafish provide a model for cancerous melanoma in humans

May 26, 2009

In a new study published in Disease Models & Mechanisms, scientists use the zebrafish to gain insight into the influence of known cancer genes on the development and progression of melanoma, an aggressive form of human skin ...

Recommended for you

Scientists overcome key CRISPR-Cas9 genome editing hurdle

December 1, 2015

Researchers at the Broad Institute of MIT and Harvard and the McGovern Institute for Brain Research at MIT have engineered changes to the revolutionary CRISPR-Cas9 genome editing system that significantly cut down on "off-target" ...

Study finds 'rudimentary' empathy in macaques

December 1, 2015

(—A pair of researchers with Centre National de la Recherche Scientifique and Université Lyon, in France has conducted a study that has shown that macaques have at least some degree of empathy towards their fellow ...

Which came first—the sponge or the comb jelly?

December 1, 2015

Bristol study reaffirms classical view of early animal evolution. Whether sponges or comb jellies (also known as sea gooseberries) represent the oldest extant animal phylum is of crucial importance to our understanding of ...

Trap-jaw ants exhibit previously unseen jumping behavior

December 1, 2015

A species of trap-jaw ant has been found to exhibit a previously unseen jumping behavior, using its legs rather than its powerful jaws. The discovery makes this species, Odontomachus rixosus, the only species of ant that ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.