Exacerbation by LDV infection of thrombocytopenia induced by monoclonal antiplatelet antibodies. (A) Control and anti-mouse platelet monoclonal antibodies were injected into groups of 3 to 4 CBA/Ht mice 1 day after (anti-CD41; 3 μg/mouse) or the same day (N1, 100 μg/mouse; F96A9K1, 300 μg/mouse) as LDV infection or administration of saline. Platelets were counted 1 day (anti-CD41) or 2 days (N1 and F96A9K1) after antibody administration. Results are shown as means ± SEM for independent experiments. (B) Anti-mouse platelet monoclonal antibody (N1, 100 μg/mouse) was administered at different times after LDV infection, as indicated, into groups of 5 CBA/Ht mice. Platelets were counted 2 days after antibody administration (○ represents each individual datum; •, means ± SEM). Control groups received neither virus nor antibody (control); virus alone 3 days before platelet count (LDV) or antibody alone 2 days before platelet counts (Ab).