Comparative Study on the Ability of Various Teratocarcinomas to Form Chimeric Mouse Embryos: (mouse...

Various embryonal carcinoma cells of different origins were compared as to the ability to form chimeric blastocysts by means of aggregating with normal 8-cell stage mouse embryos. The teratocarcinoma lines examined were OTT6050 and five newly established ones including a spontaneous testicular teratocarcinoma STT-2. The present results have revealed that distinct differences existed in the ability of colonizing blastocysts among teratocarcinomas and also among embryonal carcinoma cell lines. Since STT-2 stem cells were found to be incorporated into blastocysts most efficiently, further development of the blastocysts were examined in utero. It was found that STT-2 stem cells could be incorporated into the fetuses up to the 7-to 28-somite stages. This is the first case to demonstrate that testicular teratocarcinoma cells with the male germ cell origin have the developmental potency to participate into mouse embryogenesis.