Comprehensive validation of T- and B-cell deficiency in rag1-null zebrafish: Implication for the robust innate defense mechanisms of teleosts

Abstract rag1 −/− zebrafish have been employed in immunological research as a useful immunodeficient vertebrate model, but with only fragmentary evidence for the lack of functional adaptive immunity. rag1-null zebrafish exhibit differences from their human and murine counterparts in that they can be...

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Bibliographic Details
Main Authors: Yumie Tokunaga, Masamichi Shirouzu, Ryota Sugahara, Yasutoshi Yoshiura, Ikunari Kiryu, Mitsuru Ototake, Takahiro Nagasawa, Tomonori Somamoto, Miki Nakao
Format: article
Language:EN
Published: Nature Portfolio 2017
Subjects:
R
Q
Online Access:https://doaj.org/article/e2e2b8bb39fa4536aa0bf6e4645fb262
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Summary:Abstract rag1 −/− zebrafish have been employed in immunological research as a useful immunodeficient vertebrate model, but with only fragmentary evidence for the lack of functional adaptive immunity. rag1-null zebrafish exhibit differences from their human and murine counterparts in that they can be maintained without any specific pathogen-free conditions. To define the immunodeficient status of rag1 −/− zebrafish, we obtained further functional evidence on T- and B-cell deficiency in the fish at the protein, cellular, and organism levels. Our developed microscale assays provided evidence that rag1 −/− fish do not possess serum IgM protein, that they do not achieve specific protection even after vaccination, and that they cannot induce antigen-specific CTL activity. The mortality rate in non-vaccinated fish suggests that rag1 −/− fish possess innate protection equivalent to that of rag1 +/− fish. Furthermore, poly(I:C)-induced immune responses revealed that the organ that controls anti-viral immunity is shifted from the spleen to the hepatopancreas due to the absence of T- and B-cell function, implying that immune homeostasis may change to an underside mode in rag-null fish. These findings suggest that the teleost relies heavily on innate immunity. Thus, this model could better highlight innate immunity in animals that lack adaptive immunity than mouse models.