In Vitro Assays

In vitro Adventitious Agent Detection assays, utilizing specific cell lines, detect viruses to ensure the absence of viral contamination in cell lines and their derivatives. Texcell has developed protocols that are fully compliant with regulatory guidelines.

Lytic and/or haemadsorbing viruses are detected after inoculation of the indicator cell line with the test article. Indicator cells are examined regularly for signs of a cytopathic effect (CPE) over a period of 14 or 28 days (with a passage after a period of 14 days). Two haemadsorption assays are carried out with each of the three erythrocyte species.

  • The number of erythrocyte species used is never reduced (human group O Rhesus Negative, chicken and guinea pig)
  • Internal interference and inhibition controls are always included

For the evaluation of cell-line-derived biologicals used as medicinal products, the US FDA’s note on “Points to Consider on the Characterization of Cell Lines Used to Produce Biologicals” recommends–as a minimum measure–that in addition to monolayer culture of the same species and tissue type used in production, a normal human diploid cell line (such as MRC-5) and a monkey kidney cell line (such as Vero) should be examined over a period of 14 days; 3 detector cell lines are therefore used. For test materials that can support the growth of human cytomegalovirus, a 28-day culture period is recommended.

The detector cell lines are chosen based upon the origin of the cell line that is producing the biotherapeutic :

Cell Origin Detector Cell Line
HUMAN MRC-5, HELA, RD19, HEK294
SIMIAN VERO, LLCMK2, FRhL2
MURINE SP2/0 Ag24, NIH3T3, BalbC, 324K
HAMSTER CHO, CHOK1, BHK21
INSECT Hi5, SF9
CANINE MDCK
RABBIT RK13
HORSE NBL6
BOVINE BT
PORCINE PPK, ST

For serum or cell lines grown with FBS, Texcell provides you with the specific assay required in guidelines 9CFR 113.53 and CPMP/BWP/1793/02, and if porcine trypsin is used Texcell provides you with the specific assay required in guidelines 9CFR part113.47-53 CPMP/BWP/1793/02.