PROGEN provides a set of baculovirus cassette vectors for easy 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 under the control of 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, with the entire coding region of human IgG1 constant domains located downstream. Vectors pAc-kappa-Fc and pAc-lambda-Fc are designed for Fab fd gene fragment insertion using XhoI and SpeI recognition sites. 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.