Bovine whole-blood culture as a tool for the measurement of endotoxin activities in Gram-negative bacterial vaccines

Pyrogen detection methods: comparison of bovine whole blood assay (bWBA) and monocyte activation test (MAT)

Background

Pyrogen detection is of utmost importance in pharmaceutical industry, laboratories and health care institutions. As an alternative to the animal-consuming rabbit pyrogen test or Limulus amoebocyte lysate test, the monocyte activation test was introduced as a gold standard method in the European Pharmacopoeia. However, the monocyte activation test has not gained wide acceptance in practice.

Methods

We stimulated bovine whole blood with different endotoxin preparations (lipopolysaccharide E.coli 0127:B8 and 0113:H10), as well as the non-endotoxin pyrogens peptidoglycan and lipoteichoic acid. Prostaglandin E₂ (PGE₂) served as read out.

Results

Employing PGE₂ as read out enabled detection limits of 0.04 EU/ml for lipopolysaccharide 0127:B8, 0.25 EU/ml for lipopolysaccharide 0113:H10 and 10 μg/ml of lipoteichoic acid as well as peptidoglycan. To evaluate the bWBA test system as a possible alternative to the MAT we performed a peer-to-peer comparison of the two methods and confirmed similar sensitivities.

Conclusions

In conclusion, the bovine whole blood assay (bWBA) reproducibly enabled sensitive detection of endotoxin and non-endotoxin pyrogens and may thus become a viable alternative for pyrogen testing.