Tumorigenesis and anti-tumor immune responses in Xenopus

Ana Goyos, Jacques Robert

Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642

TABLE OF CONTENTS

1. Abstract

2. Introduction

3. Tumor occurrence in Xenopus

3.1. Xenopus ovarian tumors

3.2. Xenopus thymic lymphoid tumors

4. Tumorigenesis

4.1. In vivo models of tumorigenesis

4.2. Translocation/Chromosomal Aberration/Genomic Instability

5. Immune responses to tumor in Xenopus

5.1. NK-like effectors

5.2. MHC class I-restricted and -unrestricted CD8+ T cell effectors

6. Conclusions and Perspectives

7. Acknowledgements

8. References

1. ABSTRACT

Despite intense study, the role of the immune system in detecting (immunosurveillance), controlling and remodeling (immunoediting) neoplasia remains elusive. We present here a comparative view of the complex interactions between neoplasia and the host immune system. We provide evidence, in the amphibian Xenopus laevis, consistent with an evolutionarily conserved and crucial role of the immune system in controlling neoplasia, which involves a striking variety of anti-tumoral immune effectors including conventional CTLs, classical MHC class Ia unrestricted CTLs (CCU-CTLs) that interact with nonclassical MHC class Ib molecules, CD8 NKT-like cells and NK cells. We also review the tumors found in X. laevis with an emphasis on thymic lymphoid tumors and a rare ovarian dysgerminoma. Finally, we consider the use of X. laevis for in vivo study of tumorigenesis. Given our current knowledge, the experimental systems already established in X. laevis, and the rapid accumulation of genetic resources for the sister species Silurana (Xenopus) tropicalis, it is our conviction that these species provide an ideal alternative to the murine system for studying tumorigenesis and tumor immunity.