Their paper, titled "Resolution of the novel immune-type receptor gene cluster in zebrafish," appears online today in the Proceedings of the National Academy of Sciences.

"This is the most genetically complex system of innate immune receptors thus far described,"said principal investigator Gary Litman, PhD, Hines professor of pediatrics who works at the Children's Research Institute at the University of South Florida and All Children's Hospital. "They may be related to receptors in humans involved in natural killer cell function." Natural killer cells sense and kill malignant cells and cells infected with certain viruses.

The zebrafish, a small species of freshwater aquarium fish, increasingly serves as an animal model for the study of genetic diseases. Like humans, it has two types of immune systems innate and adaptive. Innate immune systems provide a first line of defense against foreign microorganisms. But, humans and other jawed vertebrates have also evolved more customized or adaptive immune systems, which use an arsenal of antibodies and T-cell receptors to fend off diverse pathogens and prevent repeat attacks.

Dr. Litman and his colleagues are trying to tease out details about the evolutionary transition from innate to adaptive immunity with powerful new biotechnology techniques.

They searched the genome of the zebrafish and identified a class of genes, called novel immune-type receptor (NITR) genes, which are predicted to be capable of recognizing a wide range of surface molecules. A portion of the NITR genes is very similar to variable region genes of antibodies and T-cell receptors, but the NITR genes do not undergo the compl
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Contact: Anne DeLotto Baier
abaier@hsc.usf.edu
813-974-3300
University of South Florida Health
18-Oct-2004