Abstract: The present invention provides a pseudotyped retroviral vector particle, wherein said retroviral vector particle comprises a) an envelope protein with antigen-binding activity, wherein said envelope protein is a recombinant protein that does not interact with at least one of its native receptors and is fused at its ectodomain to a polypeptide that specifically binds to a target antigen expressed on the surface of a target cell, and wherein said envelope protein is protein H of a virus of the Paramyxoviridae family, b) an envelope protein with fusion activity of a virus of the Paramyxoviridae family, and wherein said Paramyxoviridae virus is a virus of the morbillivirus genus, and wherein said virus of the morbillivirus genus is a canine distemper virus (CDV), and wherein said retroviral vector particle comprises at least one nucleic acid sequence encoding a transgene, and wherein said retroviral vector particle is a lentiviral or gammaretroviral vector particle.

Abstract: The present invention provides a pseudotyped retroviral vector particle for activating and transducing T cells, wherein said retroviral vector particle comprises a modulating protein comprising a functional ectodomain comprising an antigen binding domain specific for the antigen CD3, wherein said antigen binding domain specific for the antigen CD3 comprises a humanized and optimized scFV sequence, wherein said retroviral vector particle comprises at least one nucleic acid sequence encoding a transgene, and wherein said retroviral vector particle is a lentiviral or gammaretroviral vector particle. A pharmaceutical composition thereof is also disclosed.