Morphology of the MTHC colonies. (a through d) Examples of the various types of colonies observed in methylcellulose. Examples shown are indicative of (a) a compact colony, (b) a diffuse colony, (c) a mixed colony with a compact center, and diffuse cells surrounding and (d) a mixed halo colony with a compact center, diffuse cells radiating outward and a compact ring of cells surrounding it. (e and f ) The presence of giant cells in colonies and, for comparison, in liquid culture of Kit-expressing MTHC. (e) Shows the size comparison of a giant cell colony and a normal-sized compact MTHC colony. (f ) The same comparison in liquid culture with the arrows indicating a nonadherent giant cell in the middle of the photograph and an adherent giant cell to the extreme right.