Interlaboratory validation of the modified murine local lymph node assay based on adenosine triphosphate measurement.
BACKGROUND
The murine local lymph node assay (LLNA) is a well-established alternative to the guinea pig maximization test (GPMT) or Buehler test (BT) for the assessment of the skin sensitizing ability of drugs and chemicals. Daicel Chemical Industries Ltd. has developed a modified LLNA based on the adenosine triphosphate (ATP) content (LLNA-DA). We conducted 2 interlaboratory validation studies to evaluate the reliability and relevance of LLNA-DA.


METHODS
The experiment involved 17 laboratories, wherein 14 chemicals were examined under blinded conditions. In the first study, 3 chemicals were examined in 10 laboratories and the remaining 9 were examined in 3 laboratories. In the second study, 1 chemical was examined in 7 laboratories and the remaining 4 chemicals were examined in 4 laboratories. The data were expressed as the ATP content for each chemical-treated group, and the stimulation index (SI) for each chemical-treated group was determined as the increase in the ATP content relative to the concurrent vehicle control group. An SI of 3 was set as the cut-off value for exhibiting skin sensitization activity.


RESULTS
The results of the first study obtained in the experiments conducted for the 3 chemicals that were examined in all the 10 laboratories and for 5 of the remaining 9 chemicals were sufficiently consistent with small variations in their SI values. The sensitivity, specificity, and accuracy of LLNA-DA against those of GPMT/BT were 7/8 (87.5%), 3/3 (100%), and 10/11 (90.9%), respectively. In the second study, all the 5 chemicals studied demonstrated acceptably small interlaboratory variations.


CONCLUSIONS
In the first study, a large variation was observed for 2 chemicals; in the second study, this variation was small. It was attributed to the application of dimethylsulfoxide as the solvent for the metallic salts. In conclusion, these 2 studies provide good evidence for the reliability of the LLNA-DA.
Omori
Takashi
T
Kyoto University School of Public Health, Japan. omori@pbh.med.kyoto-u.ac.jp
Idehara
Kenji
K
Kojima
Hajime
H
Sozu
Takashi
T
Arima
Kazunori
K
Goto
Hirohiko
H
Hanada
Tomohiko
T
Ikarashi
Yoshiaki
Y
Inoda
Taketo
T
Kanazawa
Yukiko
Y
Kosaka
Tadashi
T
Maki
Eiji
E
Morimoto
Takashi
T
Shinoda
Shinsuke
S
Shinoda
Naoki
N
Takeyoshi
Masahiro
M
Tanaka
Masashi
M
Uratani
Mamoru
M
Usami
Masahito
M
Yamanaka
Atsushi
A
Yoneda
Tomofumi
T
Yoshimura
Isao
I
Yuasa
Atsuko
A
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D007509:Irritants / Q000633:toxicity*; D023441:Local Lymph Node Assay; D051379:Mice; D008808:Mice, Inbred CBA; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D018675:Toxicity Tests / Q000379:methods
D007509:Irritants; D012997:Solvents; D000255:Adenosine Triphosphate