Abstract: The present invention relates to methods of host cell transduction utilising ecotropic retroviral vector particles. The retroviral vector particle may comprise an envelope of Friend murine leukaemia virus, in particular the envelope encoded by molecular clone PVC-211 and the host cell may be engineered to recombinantly express the Reel receptor. The retroviral vector particles and methods of the invention can be used to introduce expressible polynucleotide sequences of interest into host cells with high efficiency. This results in protein production methods with higher yield (mg/L) and a reduction in manufacturing costs that could be used in a range of applications including for example, the production of therapeutic proteins, vaccines and antibodies.