Antigenic material captured by B cells in the presence of enzyme inhibitors is available for subsequent processing and T-cell activation. MD4 B cells were incubated at 37°C for 1 hour with either culture medium, sHEL, J558L, or J558LmHEL target cells, and in the presence or absence of 25 μM latrunculin B. MD4 B cells were then selected magnetically (purity > 85%) before an overnight incubation at 37°C with 1H11-34 T-cell hybridoma. T-cell activation was measured by determining concentrations of IL-2 in the supernatants by ELISA. Black and white bars correspond to 2 independent experiments.