Pyrogen detection is one of the mandatory release tests for sterile parenteral drugs. Today, the two main test methods in use are the bacterial endotoxin test (or LAL test) and the Rabbit Pyrogen Test.
Another test method that has increasingly been used the past few years does not need animals for pyrogen detection, in line with current European regulatory guidelines. Indeed, the monocyte activation test (MAT) uses human monocytic cells to mimic the human reaction to pyrogens in vitro.
Yet, the MAT remains little known. Its adoption rate is growing only slowly despite having been described as a compendial method in the European Pharmacopeia since 2010 (chapter 2.6.30). Recently, several test solutions have been commercialized, allowing an easy adoption and use in the lab.
The various available kits use different sources of monocytes. The solutions are based either on cryopreserved whole blood, peripheral blood mononuclear cells (PBMC) or monocytes from the Mono-Mac-6 cell line (MM6).
The MM6 cell line, which has been validated for the use in the MAT, has sometimes been questioned over its ability to detect non-endotoxin pyrogens (NEPs). To demonstrate its performance, tests have been performed using a wide panel of toll-like receptor (TLR) ligands. TLRs are monocytic receptors responsible for the detection of pyrogens. This article gives an overview of the results obtained.