Secondary bioactive compound groups were isolated from the Dendrobium orchid methanol extracts by chromatographic techniques. Each group has up to 5 pure compounds. I am confused for the selection of antibodies to do western blot analysis of HeLa and U-251 cell lines treated by these compounds group. I also want to do flow cytometry on compound treated these cells but have no idea about this. Are flow cytometry and western blot work similar?  Any different protocol for flow cytometry without using antibodies or by using only propidium iodide.