In 1963, at the university of Bordeaux, I started studying the immune system of tadpoles and earthworms, but most of the research done by my colleagues and me was achieved from 1970 to 2000 at the Basel Institute for Immunology. We used essentially the amphibian Rana catesbiana and many species of Xenopus to study phylogenetic and ontogenetic aspects of the Vertebrate immune system. Our approach was physiological (characteristics of immune responses, affinity maturation, kinetics, etc.), molecular (immunochemistry of lymphocyte membrane, monoclonal antibody reagents, etc.), genetical (formal genetics, segregation of polymorphisms, molecular biology), and aimed at understanding the generation of antibody diversity, as well the nature and the role of major histocompatibility complex and T-cell receptors in these species.

The main subjects were

  • Ontogeny of the immune response in tadpoles, role of the thymus.
  • Discovery of a Major Histocompatibility gene Complex (MHC)
  • TB cell collaboration, role of the MHC.
  • Mechanism of self-tolerance.
  • Effect of metamorphosis on the immune system.
  • Characterization of the immunoglobulin locus.
  • The role of somatic mutations in the generation of antibody diversity.
  • Heavy chain class switch.
  • Polyploidy and the immune system.
  • Making tadpoles by nuclear transplantation with lymphocyte nuclei.
  • Discovery of a novel vertebrate immunoglobulin superfamily member CTX (cortical thymocyte marker of Xenopus)

Some specific methods were developed on the way.

  • Breeding of strains of Xenopus.
  • Production of isogenic clones of Xenopus.
  • Discovery of a thymic lymphoid tumor and development of lymphoid tumor cell lines in vitro.
  • In situ hybridization on chromosomes (Ig, MHC).
  • Somatic hybrids between Xenopus lymphocytes and mouse myeloma cells.
  • Raising monoclonal antibodies to Ig heavy and light chains and to MHC class I and class II.

In addition several expeditions were organized in Africa in 1975, 1979, 1994, with colleagues from Geneva and Bristol to collect and discover new species of Xenopus that were then bred in the aquarium of the Institute. For people who might be interested some of the breeding nuclei have been transferred to the university of Rennes: