A packaging cell line capable of complementing recombinant adenoviruses based on serotypes from subgroup B, preferably adenovirus type 35. The cell line is preferably derived from primary diploid human cells transformed by adenovirus E1 sequences either operatively linked on one or two DNA molecules, the sequences operatively linked to regulatory sequences enabling transcription and translation of encoded proteins. Also, a cell line derived from PER.C6 that expresses functional Ad35-E1B sequences. The Ad35-E1B sequences are driven by the E1B promoter and terminated by a heterologous poly-adenylation signal. The new cell lines are useful for producing recombinant adenoviruses. The cell lines can be used to produce human recombinant therapeutic proteins such as human antibodies. In addition, the cell lines are useful for producing human viruses other than adenovirus such as influenza, herpes simplex, rotavirus, and measles.