Fig. 1. Derivation of ZtA6 feeder cells from tumor-like hypertrophied testis. (A) ZtA6 cells included heterogeneous testicular cell types, including epithelial and fibroblast cells. (B) Many cells showed phagocytic activity in terms of the uptake of latex beads, which is characteristic of mammalian Sertoli cell lines (Tokuda et al., 1992; Rassoulzadegan et al., 1993). Scale bars: 50 µm.