Chimeras

Thymus/Lymphocyte Embryonic Chimeras

Chimeras made by exchanging the anterior and posterior regions of two embryos at 24 hrs after fertilization. One embryo was from an A8 albino (white skin and red eyes) strain and the other embryo was from a J (green) strain. From Basel Institute for Immunology Annual Report 1982

Another unique advantage of X. laevis for experimental immunology is the possibility to manipulate frog embryos very early in development to generate chimeras. For example, the anterior one third of a 24-h-old tail bud embryos containing the thymus anlagen can be fused by microsurgery to the posterior two-thirds of a MHC-mismatched embryos that contains the enlagen of all hematopoietic cells (Flajnik et al., 1985). Chimeras can also be made between embryos of different ploidy to follow the fate of a particular precursor population during development (Turpen, 1998). In summary, chimeras provide an excellent in vivo experimental system to study hematopoiesis, thymic education, tolerance and MHC restriction.