Antigen adsorption induces silica/DODAB aggregation. Size distribution and zeta-potential (ζ) for dispersions in 5 mM Tris.HCl, pH 7.4. In (A), 500 μg/ml 18 kDa-hsp M. leprae. In (B), 0.1 mg/ml silica. In (C), 0.1 mg/ml silica and 0.05 mM DODAB BF dispersion. From D to E, 0.1 mg/ml silica, 0.05 mM DODAB BF dispersion and 18 kDa-hsp M. leprae at 0.005 (D), and 0.05 mg/ml (E). Interaction between components in the mixtures took place over 1 h before measurements. In each subfigure, mean zeta-potential and diameter ± SE are quoted.