Cloned 3T6 cell line from CD-1 mouse fetal molar dental papillae.

Only primary pulpal cell cultures and one virally transformed mouse cell culture have been formally reported in the literature to synthesize proteins such as phosphophoryn which are unique to dentin matrix. In the present study, a mixed culture was derived from dental papilla cells of 18-19 fetal day CD-1 mouse mandibular first molars, maintained on a 3T6 plating regimen, and subsequently cloned after 28 passages. This cloned cell line (MDPC-23) exhibited several unique features, some of which were characteristic of odontoblasts in vivo. The features of this cell line included (1) epithelioid morphology of all cells with multiple cell membrane processes, (2) high alkaline phosphatase activity in all cells, (3) formation of multilayered nodules and multilayered cultures when maintained in ascorbic acid and beta-glycerophosphate, and (4) expression of two markers for odontoblast differentiation, i.e. dentin phosphoprotein and dentin sialoprotein.