Single vector constructs for expression of a functional antibody molecule are described. The vectors have a self-processing cleavage site between two heterologous DNA coding sequences allowing for expression of two coding sequences using a single promoter. Exemplary vector constructs comprise a foot and mouth disease virus (FMDV) 2A sequence. The vector constructs can be used in methods relating to antibody delivery and therapy and in the production of a biologically active antibody or fragment thereof.