Indirect immunostaining of human megakaryocytes with proplatelet formation. The collected megakaryocytes that were derived from peripheral blood CD34⁺ cells stimulated with 10 ng/mL TPO and 10 ng/mL SCF were incubated in the absence of antibodies in a 96-well tissue culture plate for 24 hours. After fixation, megakaryocytes were exposed to the anti-GP-IIb MoAb (5B12), followed by staining with biotinylated antimouse immunoglobulins and alkaline phosphatase-conjugated streptavidin. Megakaryocytes and proplatelets were stained with anti-GP-IIb MoAb (bar, 50 μm).