Quantitative correspondence between the in vivo and in vitro activity of teratogenic agents

We have tested 74 teratogenic and 28 nonteratogenic agents in a recently developed in vitro teratogen assay system. The assay identifies teratogens by their ability to inhibit attachment of ascites tumor cells to plastic surfaces coated with concanavalin A. There is a qualitative agreement between in vivo animal data and in vitro activity for 81 of the 102 agents (79%). Quantitative analysis shows a highly significant correlation coefficient of 0.69 between the inhibitory in vitro dose and the lowest reported teratogenic dose for 54 of the 60 inhibitory teratogens. The doses analyzed ranged over 5 orders of magnitude. We interpret these results to mean that attachment inhibition in concert with other, complementary, in vitro assay systems can become a useful method for the assessment of the teratogenic potential of environmental agents.