Defensin stimulates the internalization of ¹²⁵I-Lp(a) by vascular smooth muscle cells. ¹²⁵I-Lp(a) (15 nmol/L) was incubated with HVSMC for 4 hours at 37°C in the presence of the indicated concentrations of defensin. The cells were washed and cell surface bound and internalized radioactivity was measured as described. (▪) Total cell-associated Lp(a); (♦) internalized Lp(a); (⊡) surface-bound Lp(a). The mean ± SD of three experiments is shown.