THE DEVELOPMENT IN VITRO OF CHIMERIC AGGREGATES OF DISSOCIATED EMBRYONIC CHICK AND MOUSE CELLS

Abstract

Dissociated cells from various organ rudiments of chick and mouse embryos when intermixed in suspension cultures, readily aggregated and combined to form composite, chimeric tissues. Under suitable conditions of culture, such reconstituted tissues differentiated histotypically. This communication reports on combinations of chondrogenic, nephrogenic, and hepatogenic cells of chick and mouse embryos and S91 mouse melanoma cells. In aggregates of intermixed chick and mouse cells of same type (i.e., chick and mouse chondrogenic cells) the cells reconstructed a uniform fabric which differentiated histotypically into a chimeric tissue consisting of interspersed chick and mouse cells. In aggregates of intermixed chick and mouse cells of different types (i.e., chick nephrogenic and mouse chondrogenic cells) the cells became associated according to type and formed separate groupings which developed in accordance with the original histogenetic properties of the cells. Due to the clear morphological differences between chick and mouse cells, it was possible precisely to identify and localize them in the chimeric aggregates. The evidence thus obtained suggested conclusively that (a) in the course of tissue reconstruction the dissociated embryonic cells became grouped preferentially, according to their original type identities, regardless of their generic origin, and (b) under the present experimental conditions no transformation of one cell type to another was observed.