(A) HIV infection and inhibition thereof by OKT4A MoAbs at day 5 of megakaryopoietic cell culture (representative results from the same experiment shown in Fig 2). Cells preincubated or not with 1 to 5 μg OKT4A MoAb were infected with 0.1 m.o.i. NL4-3. After extensive washing, MoAb was added again and cells maintained in culture medium. Results from BaL-1 infection of day 5 MKs are also shown. UT-7 cells challenged with infectious NL4-3 and MKs treated with heat-inactivated virus were used as negative controls. (•) MK and NL4-3; (▪) MK + 1 μg OKT4A + NL4-3; (□) MK + 5 μg OKT4A + NL4-3; (○) UT-7 + NL4-3; (▴) MK-inactivated NL4-3; (▵) MK BaL-1. (B) RT-PCR of total RNA isolated from day 12 harvested cells infected at day 0 or day 5 with infectious or heat-inactivated (inactiv.) NL4-3 or infectious BaL-1 strain. CEM and primary monocytes (Mon.), infected with NL4-3 or BaL-1, respectively, were used as positive controls. β₂m RT-PCR was performed on MKs cells for mRNA normalization.