Abstract: The present invention relates to a method for selecting a host cell population expressing a functional fusion protein comprising at least one epitope-providing amino acid sequence (epitope-tag) and the amino acid sequence of a protein that is expressed on the surface of said host cell. Preferably, the amino acid sequence comprises an alpha or beta chain of a T-cell receptor. The present invention further relates to uses of said functional T-cell receptor (TCR) alpha or beta chain fusion protein in medicine, in particular in adoptive transfer.