{HEAD ~ The method} for {TAIL ~ the cultivation} of primary cells may be one step in a method for the amplification of viruses, wherein the cells are then infected with a subject virus and the infected cells are cultivated in serum free medium until progeny virus is produced 
for
{ HEAD ~ The method } for { TAIL ~ the cultivation } of primary cells may be one step in a method for the amplification of viruses , wherein the cells are then infected with a subject virus and the infected cells are cultivated in serum free medium until progeny virus is produced
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