Scientists in the Netherlands wrote in their online-publication in „vaccine”: „Safety requirements stipulate the performance of the in vivo Histamine Sensitization (HS) test for quality control of acellular pertussis (aP) vaccines”. For reasons of reproducibility and animal welfare concern, they developed an in vitro assay.
The assay would reflect the mechanism of histamine sensitization and „is based on cAMP production in A10 cells to residual pertussis toxin (PT).” The scientists showed that PT induces cAMP levels in a dose-dependent manner while the sensitivity of the assay equals the sensitivity of the HS test. „Neither the individual components nor the combination vaccine DTaP-IP did affect the assay.“ The scientists declare, „the cAMP assay meets the criteria for specificity and sensitivity and therefore might be a promising candidate to replace the HS test.”

You will find te publication here:
http://www.sciencedirect.com/science/article/pii/S0264410X09017721