In the HIST, 40 mice are used in four doses for each preparation by injecting the test substance into its abdominal cavity.

The new test is based on CHO cells, an immortalised cell line from Chinese dwarf hamster ovaries. The cell cluster assay examines acellular vaccines, i.e. those that contain purified antigens of the pertussis pathogen Bordatella pertussis. It was developed to test for residual levels of pertussis toxin, a protein produced by the pertussis bacterium.

The cell cluster assay has been used by industry in bulk tests for many years, but a standardised protocol has only recently been developed.

A reference study involving 14 laboratories from Europe, North America and Asia has confirmed the suitability of this test.

Literature:
Markey K, Douglas-Bardsley A, Hockley J, Le Tallec D & Costanzo A (2018). Calibration of pertussis toxin BRP batch 1 in a standardised CHO cell-based clustering assay. Pharmeur Bio Sci Notes 2018: 112-123. https://www.ncbi.nlm.nih.gov/pubmed/30272557

Further information:
https://www.edqm.eu/en/news/ph-eur-replace-histamine-sensitisation-test-hist-residual-pertussis-toxin-testing
https://www.edqm.eu/en/Biological-Standardisation-Programme-mission-60.html