Cells in the upstream bioreactor produce viral vector particles, which
flow into a downstream chromatography column. The column's packed bed
retains impurities (host-cell DNA/protein, empty capsids) while letting full,
correctly-assembled vector particles pass through; the purified stream is
then dispensed into vials at fill-finish.
yield = particles_out / particles_in
purity = full_vector / (full_vector + impurities) after column
titer = vg / mL of purified pool
- Vector type — AAV yields higher titer per batch; lentivirus is larger and yields fewer particles per cell but integrates its payload.
- Production scale — sets the upstream production rate (particles generated per second in the bioreactor).
- Purification stringency — a stricter column rejects more impurities (raising purity) but also rejects more real product (lowering yield) — the classic downstream trade-off.
- Run batch — starts a production run; watch particles travel bioreactor → column → vials in real time.