PROGEN provides a set of baculovirus cassette vectors to facilitate the insertion of heavy and light chain Fv or Fab domain coding regions, enabling the expression of complete immunoglobulins. The gene elements for IgG expression were sequentially cloned into pAcUW51. The heavy chain gene cassette, preceded by the authentic IgG signal sequence from IgG1 (subgroup VHIII), is controlled by the polyhedrin promoter. In pAc-kappa-CH3 and pAc-lambda-CH3, the recognition sites of restriction endonucleases XhoI and NheI allow the insertion of a VH gene fragment, followed by the entire coding region of human IgG1 constant domains. Alternatively, vectors pAc-kappa-Fc and pAc-lambda-Fc are designed for the insertion of a Fab fd gene fragment using the recognition sites of restriction endonucleases XhoI and SpeI. The light chain gene cassette elements, starting with the authentic signal sequence of the human kappa or lambda chain, are placed in opposite orientation to the heavy chain operon under the control of the p10 promoter.