Role of phagocytosis in LDV-mediated thrombocytopenia. (A) Antiplatelet antibodies (polyclonal rabbit IgG, 1 μg/mouse; monoclonal N1 IgG2a and F96A9K1, 100 μg/mouse) were administered 1 day after LDV infection in groups of 4 CBA/Ht mice. Animals were treated with PBS-containing or clodronate-containing liposomes (200 μL) as indicated 36 hours before antibody administration. Control mice were infected but received saline instead of antiplatelet antibody. Platelets were counted 2 days after antibody administration (results shown as means ± SEM). Experiment with polyclonal antibody was independent from experiment with monoclonal antibodies. (B) IgG (3 μg) purified from polyclonal anti-mouse platelet rabbit serum (anti-plt Ab) or control rabbit IgG was administered 1 day after LDV infection in groups of 4 CBA/Ht mice. Animals were treated with 5 daily doses of 4 mg total human IgG, where indicated, starting 3 days before antibody administration. Platelets were counted 1 day after antibody administration. ○ represents each individual datum; •, means ± SEM.