Comparison of flow cytometry and immunohistochemistry in non-radioisotopic murine lymph node assay using bromodeoxyuridine.
Non-radioisotopic local lymph node assay (LLNA) employing 5-bromo-2'-deoxyuridine (BrdU) with flow cytometry (FACS) or immunohistochemistry (IHC) is gaining attention due to a regulatory issue of using radioisotope, (3)H-thymidine, in vivo in traditional LLNA. In this study, to compare the performance of these non-radioisotopic endpoints, 7 chemicals with known sensitizing potencies were examined in LLNA. Mice were topically treated with chemicals or vehicle on both ears for 3 days. After intraperitoneal injection of BrdU, bilateral lymph nodes were isolated separately and undergone respectively, FACS or IHC to determine BrdU incorporated lymph node cells (LNCs). Weight and histology of treated ears were also examined to evaluate chemical-induced edema and irritation. Both FACS and IHC could successively identify the skin sensitizers from non-sensitizers. Comparison of FACS and IHC with traditional LLNA revealed that FACS has a higher sensitivity although both assays produced comparable sensitivity and performance to traditional LLNA. In conclusion, non-radioisotopic LLNA using FACS and IHC can successfully detect sensitizers with a good correlation to traditional LLNA. Notably, FACS showed almost equivalent sensitivity and accuracy to traditional LLNA.
Jung
Kyoung-Mi
KM
Amorepacific Corporation R&D Center, Giheung-gu, Yongin-si, Republic of Korea.
Bae
Il-Hong
IH
Kim
Bae-Hwan
BH
Kim
Wang-Ki
WK
Chung
Jin-Ho
JH
Park
Young-Ho
YH
Lim
Kyung-Min
KM
D000818:Animals; D001973:Bromodeoxyuridine / Q000032:analysis* / Q000378:metabolism; D002452:Cell Count; D004423:Ear / Q000473:pathology; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D007150:Immunohistochemistry / Q000379:methods*; D023441:Local Lymph Node Assay; D008198:Lymph Nodes / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009929:Organ Size / Q000187:drug effects
D001973:Bromodeoxyuridine