Plasma from some cancer patients inhibits adenoviral Ad5f35 vector transduction of dendritic cells

Background: Pooled AB serum is often used as a media supplement for cell culture but it has the potential to transmit infectious diseases. To avoid this risk, we used autologous plasma as a media supplement for manufacturing dendritic cells (DCs) for cancer immunotherapy. We noticed inconsistencies in the DCs and investigated their nature and cause.

Methods: Adenovirus human epidural growth factor receptor 2 (adHER2/neu) DCs for 21 patients were manufactured from autologous peripheral blood monocytes that were treated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4 for 3 days, transduced with Ad5f35HER2ECTM and then treated with lipopolysaccharide and interferon (IFN)-γ for 1 day. The cells were cultured in RPMI-1640 supplemented with either 10% heat inactivated autologous or AB plasma.

Results: Twenty-eight adHER2/neu DCs were manufactured for 21 patients using autologous plasma and 68 were manufactured for 20 of those patients using AB plasma. The expression of human epidural growth factor receptor 2 (HER2/neu) was less for DCs manufactured with autologous plasma (70.3 ± 33.3% versus 86.1 ± 22.8%; P <0.01). Manufacturing adHER2/neu DCs using monocytes from three healthy subjects and plasma from one patient with low HER2/neu expression (18%) resulted in low HER2/neu expression by all three DCs (13%, 16% and 23%). Analysis of the levels of 1322 proteins in eight plasma samples associated with low HER2/neu expression and in 12 associated with high HER2/neu expression revealed that the levels of 14 predicted HER2/neu transduction efficiency.

Conclusion: The manufacture of adHER2/neu DC using autologous plasma as a media supplement resulted in inconsistent HER2/neu expression. It is likely that variability in the levels of multiple proteins in autologous plasma contributed to low HER2/neu expression.