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The Local Lymph Node Assay
Published in Francis N. Marzulli, Howard I. Maibach, Dermatotoxicology Methods: The Laboratory Worker’s Vade Mecum, 2019
The available evidence indicates that the local lymph node assay compares favourably with guinea pig predictive tests and indeed with the results of human maximization tests (Basketter et al., 1994). The local lymph node assay offers a number of important advantages. Not least of these is that, compared with guinea pig methods, the assay is relatively rapid and cost-effective to perform. Moreover, the readout is objective and quantitative and, unlike some of the more sensitive guinea pig tests, adjuvant treatment is not required. Exposure of mice is via the relevant route, and the assay can be used for the assessment of colored materials and dyestuffs that may be the cause of interpretative difficulties in guinea pig assays where erythematous reactions are measured. Importantly, as decisions in the local lymph node assay are reached on the basis of events associated with the induction phase of sensitization, there is no necessity to elicit hypersensitivity reactions, thereby reducing the trauma to which test animals are potentially subject.
An in vitro human assay for evaluating immunogenic and sensitization potential of a personal care and cosmetic product
Published in Toxicology Mechanisms and Methods, 2021
Andrew D. Monnot, Kevin M. Towle, Shaheda S. Ahmed, Anne M. Dickinson, Ernest S. Fung
Human Repeat Insult Patch Tests (HRIPTs) have been used by clinicians for years as a confirmatory test in the evaluation of skin sensitizers. However, it has been argued that HRIPTs should be conducted rarely and in cases where the benefits outweigh the risk (Basketter and Kimber 2009). One of the most common and established methods for evaluating the skin sensitization potential of a chemical or product is the mouse Local Lymph Node Assay (LLNA) (Kimber et al. 1989; Kimber et al. 1991). Over the past ten years, there has been a global push to develop new methods for skin sensitizing potential that remove the need for animal testing. For example, in 2018, California’s legislators approved a bill to expand its existing prohibition of the sale of cosmetic products and ingredients tested on animals (Sanzo et al. 2018).
Evaluation of the skin-sensitizing potential of gold nanoparticles and the impact of established dermal sensitivity on the pulmonary immune response to various forms of gold
Published in Nanotoxicology, 2020
K. A. Roach, S. E. Anderson, A. B. Stefaniak, H. L. Shane, G. R. Boyce, J. R. Roberts
The Local Lymph Node Assay (LLNA) was performed in accordance with previously-established standardized protocols (Basketter et al. 2002). Accordingly, mice (n = 8 per group) were exposed topically to vehicle control (50% DMSO in distilled, deionized water), increasing concentrations of Au or AuNP, or positive control (10% AuCl3) on the dorsal sides of both ears (25 µL per ear) for three consecutive days (days 1, 2, and 3) (Figure 1). Following two days of rest, on day 6, mice were injected intravenously via the lateral tail vein with 20 µCi [3H]-thymidine (Dupont NEN, specific activity 2 Ci/mmol). Five hours after the [3H]-thymidine injection, mice were euthanized via CO2 asphyxiation and the left and right auricular lymph nodes (ALN) were excised from each mouse and pooled. Single-cell suspensions were prepared, and following overnight incubation in 5% trichloroacetic acid (TCA), samples were analyzed using a Packard Tri-Carb 2500TR liquid scintillation counter. Stimulation indices (SI) were calculated by dividing the mean disintegrations per minute (DPM) per test group by the mean DPM for the vehicle control group.
Non-animal methods to predict skin sensitization (I): the Cosmetics Europe database*
Published in Critical Reviews in Toxicology, 2018
Sebastian Hoffmann, Nicole Kleinstreuer, Nathalie Alépée, David Allen, Anne Marie Api, Takao Ashikaga, Elodie Clouet, Magalie Cluzel, Bertrand Desprez, Nichola Gellatly, Carsten Goebel, Petra S. Kern, Martina Klaric, Jochen Kühnl, Jon F. Lalko, Silvia Martinozzi-Teissier, Karsten Mewes, Masaaki Miyazawa, Rahul Parakhia, Erwin van Vliet, Qingda Zang, Dirk Petersohn
Existing LLNA data were available for all 128 substances. These data were collected from the literature, the NICEATM LLNA database (which includes data from studies from 1989 to 2010), included in NTP’s integrated chemical environment (Bell et al. 2017) and from the proprietary database of the Research Institute for Fragrance Materials (RIFM). The LLNA studies were conducted according to the OECD test guideline 429 ‘Skin sensitization: local lymph node assay’ (OECD 2010) or similar protocols. For inclusion of positive/sensitizing results, the LLNA EC3 value (i.e. estimated concentration [by interpolation] of a substance expected to produce a stimulation index of 3, the threshold value for a substance to be considered a sensitizer in the LLNA), highest dose tested and vehicle identity were required. In total, 575 LLNA studies were included that covered a broad spectrum of EC3 values, ranging from 0.001% (1,4-phenylenediamin; CAS no. 106–50-3) to 95.8% (Xylene; CAS no. 1330–20-7), and also contained 92 negative studies. For approximately 45% (57/128) of the substances, more than one LLNA study was available.