A Replication-Competent Retrovirus Arising from a Split-Function Packaging Cell Line Was Generated by Recombination Events between the Vector, One of the Packaging Constructs, and Endogenous Retroviral Sequences

摘要: Previously we reported the presence of a replication-competent retrovirus in supernatant from vector-producing line derived widely used split-function amphotropic packaging cell line. Rigorous routine screening all retroviral stocks produced our laboratory has not, previously or since, indicated such virus. Replication-competent retroviruses have never been laboratory, and stringent routinely lines not revealed any helper viruses. Therefore, it is highly unlikely that this virus represents an adventitious cross-contaminant had imported unknowingly with stocks. PCR studies DNA infected Northern blot analysis reverse transcriptase RNA cells suggest arose by recombination events, at sites partial homology, between sequences vector, one constructs, endogenous elements. These recombinations were present initial stock line, indicating these events occurred while was being passaged for harvest