The following papers were accepted for publication simultaneously and, as a result of an administrative error, they appeared in separate issues of Gene Therapy. The publishers would like to apologise for this error.

Chan et al. A novel human suspension culture packaging cell line for production of high-titre retroviral vectors. Gene Therapy 2001; 8: 697–703.

Pizzato et al. Development of a suspension packaging cell line for production of high titre, serum-resistant murine leukemia virus vector. Gene Therapy 2001; 8: 737–745.