One day before each vaccination, DC were pulsed (co-cultured) with tumor lysate overnight, washed, and the final product was tested for sterility by Gram stain, mycoplasma and endotoxin testing prior to injection.
NWBO has said for 20 years that a big advantage of DCVax-L is that it is one batch per patient and frozen until use. The UCLA process used in the combo trials has a fresh batch made for every dose.