an existing bovine papilloma virus-based expression vector , pbv-1mtha , was modified to allow transformed x63ag8-653 myeloma cells , nih 3t3 fibroblasts and c127 mammary tumor cells to stably carry multiple copies of the vector , to express the inserted cdna encoding a single interleukin constitutively , and to secrete the interleukin in high quantities .
C0016030
fibroblasts
C0007634
cells