Submitted to: International Embryo Transfer Society Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: November 13, 1995
Publication Date: N/A
Conditions were examined for derivation of embryonal carcinoma (EC) cell lines and teratoma or teratocarcinoma formation from arm animal embryos in mice with severe combined immunodeficiency (SCID). Day-7 blastocysts and day-13 embryonic discs (ED) from pigs, sheep, and cowe were surgically implanted in the kidney capsule, testis, and shoulder of SCID mice. Pig and sheep embryos were produced in vivo. Cow day-7 blastocysts were from an IVM-IVF culture system and the day-13 ED's were from that same system but the blastocysts were cultured a further six days in a luteal-phase sheep uterus. For controls, D3 mouse stem cells and STO mouse fibroblasts were injected at 1 million per cell/site. After 6 weeks, mice were examined for tumors, which were then cultured to isolate EC cells, tested for species identity by PCR, and examined histologically. The D3 and STO cells produced tumors at all three sites for all fivev mice. Cow blasto- cysts produced no tumors on either day-7 (9 mice) or day-13 (14 mice). Pig day-7 blastocysts produced 1 tumor (12 mice) but the pig day-13 ED's produced 11 tumors (13 mice). Sheep day-7 blastocysts produced 3 tumors (8 mice) and the day-13 ED's yielded 8 tumors (10 mice). In tissue cultures, all tumors yielded fibroblasts, macrophages, and epithelial cells. Some tumors contained hair,bony fragments, neuronal cells, muscle fibers, and ciliated epithelium. Using species-specific primers, PCR identified all tumors as containing either pig or sheep tissue. Histolog- ical examination of tumors with Maisson-Trichrome stain showed teratoma formation which included epithelium, cartilage and connective tissue types. The SCID mouse xenografts may be useful for testing putative ES cell lines and may provide a means of deriving EC cells for farm animals.