Host: The Japanese Society of Toxicology
Name : The 50th Annual Meeting of the Japanese Society of Toxicology
Date : June 19, 2023 - June 21, 2023
[Background and purpose] LLNA: BrdU-ELISA (LLNA-BrdU) is widely used to evaluate the skin sensitization potential of chemicals as well as LLNA-RI. In LLNA, estimated concentration (EC) that chemicals induce positive response is used as indicator of skin sensitization potency, and EC1.6 in LLNA-BrdU and EC3 in LLNA-RI can be used for GHS sub-categorization and quantitative risk-assessment. Since there have been no reports of quantitative comparison for EC1.6 and EC3, relationship between these two parameters was statistically analyzed based on existing data, and regression equation was constructed. Additionally, practicality of the equation was examined by comparing predicted EC3 with the actual value.
[Materials and Methods] Regression analyses were performed on the existing data of EC3 and EC1.6 (15 sensitizers) listed in the performance standard of LLNA, and the optimal regression equation was determined based on R2 values. We estimated the 95% confidence interval of existing EC3 data (34 sensitizers). In addition, practicality was examined by comparing predicted EC3 with the actual EC3 using 32 sensitizers, in which the actual EC1.6 and EC3 were known, listed in ICCVAM LLNA: BrdU-ELISA evaluation report.
[Results] The established regression equation (LogEC3=0.972LogEC1.6+0.118(±0.618)) showed good predictive accuracy for EC3 and it was confirmed to be practical: 27/32 sensitizers were within the estimated variation range and deviations of estimated EC3 for remaining 5 sensitizers from the estimated range were minimal.
