title: Further development of LLNA:DAE method as stand-alone skin-sensitization testing method and applied for evaluation of relative skin-sensitizing potency between chemicals.
abstract: To date, there has been no well-established local lymph node assay (LLNA) that includes an elicitation phase. Therefore, we developed a modified local lymph node assay with an elicitation phase (LLNA:DAE) to discriminate true skin sensitizers from chemicals that gave borderline positive results and previously reported this assay. To develop the LLNA:DAE method as a useful stand-alone testing method, we investigated the complete procedure for the LLNA:DAE method using hexyl cinnamic aldehyde (HCA), isoeugenol, and 2,4-dinitrochlorobenzene (DNCB) as test compounds. We defined the LLNA:DAE procedure as follows: in the dose-finding test, four concentrations of chemical applied to dorsum of the right ear on days 1, 2, and 3 and dorsum of both ears on day 10. Ear thickness and skin irritation score were measured on days 1, 3, 5, 10, and 12. Local lymph nodes were excised and weighed on day 12. The test dose for the primary LLNA:DAE study was selected as the dose that gave the highest left ear lymph node weight in the dose-finding study, or the lowest dose that produced a left ear lymph node of over 4 mg. This procedure was validated using nine different chemicals. Furthermore, qualitative relationship was observed between the degree of elicitation response in the left ear lymph node and the skin sensitizing potency of 32 chemicals tested in this study and the previous study. These results indicated that LLNA:DAE method was as first LLNA method that was able to evaluate the skin sensitizing potential and potency in elicitation response.
authors: Corporate Research Center, Daicel Corporation, 1239 Shinzaike, Aboshi-ku, Himeji, Hyogo, 671-1283, Japan; Faculty of Engineering, Dept. of Materials Science and Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogoya, Yokohama, Kanagawa, 240-8501, Japan.
authors: Kunihiko
authors: K
authors: Yamashita
authors: Shinsuke
authors: S
authors: Shinoda
authors: Saori
authors: S
authors: Hagiwara
authors: Hiroshi
authors: H
authors: Itagaki
mesh_terms: D000171:Acrolein / Q000009:adverse effects / Q000031:analogs & derivatives*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004423:Ear; D005054:Eugenol / Q000009:adverse effects / Q000031:analogs & derivatives*; D005260:Female; D023441:Local Lymph Node Assay; D008198:Lymph Nodes / Q000276:immunology*; D008808:Mice, Inbred CBA; D009579:Nitrobenzoates / Q000009:adverse effects*; D023422:Skin Irritancy Tests / Q000379:methods*
chemical_list: D009579:Nitrobenzoates; C080043:hexyl cinnamic aldehyde; D005054:Eugenol; C036643:isoeugenol; C109832:2,4-dinitrobenzoic acid; D000171:Acrolein