A ranavirus-induced thymus cDNA library was constructed from Chinese giant salamander, the largest extant amphibian species. Among the 137 putative immune-related genes derived from this library, these molecules received particular focus: immunoglobulin heavy chains (IgM, IgD, and IgY), IFN-inducible protein 6 (IFI6), and T cell receptor beta chain (TCRb). Several unusual features were uncovered: IgD displays a structure pattern distinct from those described for other amphibians by having only four constantdomains plus a hinge region. A unique IgY form (IgY(DFc)), previously undescribed in amphibians, is present in serum. Alternative splicing is observed to generate IgH diversification. IFI6 is newly-identified in amphibians, which occurs in two forms divergent in subcelluar distribution and antiviral activity. TCRb immunoscope profile follows the typical vertebrate pattern, implying a polyclonal T cell repertoire. Collectively, the pioneering survey of ranavirus-induced thymus cDNA library from Chinese giant salamander reveals immune components and characteristics in this primitive amphibian. Developmental and Comparative Immunology, 2014, in press. Rong Zhu, Zhong-Yuan Chen, Jun Wang, Jiang-Di Yuan, Xiang-Yong Liao, Jian-Fang Gui, Qi-Ya Zhang. State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. zhangqy@ihb.ac.cn