局部淋巴结试验与局部封闭斑贴试验应用于化妆品皮肤变态反应评价的比较

目的 通过局部淋巴结试验法和局部封闭斑贴试验应用于化妆品皮肤变态反应的比较,探讨局部淋巴结试验应用于化妆品成品的可行性。方法 采用局部淋巴结试验与体内局部封闭斑贴试验对标准的阳性物以及市面上的2种染发剂进行评价。结果 局部淋巴结试验表明,2种染发剂的SI值<1.8,均为阴性,判断结果与局部封闭斑贴试验结果一致。结论 局部淋巴结试验相对局部封闭斑贴试验具有检验周期短、测试简便、评价客观等优点,是一种较好的用于评价染发类态产品过敏反应的替代方法。     

Screening Petrochemicals for Contact Hypersensitivity Potential: A Comparison of the Murine Local Lymph Node Assay with Guinea Pig and Human Test Data

Over the last few years, the Murine Local Lymph Node Assay (MLLNA)has received considerable attention as a more quantitative,less expensive alternative to the guinea pig assays currentlyemployed to identify potential human contact allergens. At thistime, several companies are involved in both independent andjoint efforts to validate the MLLNA with their products. Thisreport describes the preliminary results of an Exxon-sponsoredresearch effort to validate the assay with selected materialsthat are representative of our company's diverse chemical andpetroleum product groups. Nine test materials were chosen forwhich there already existed guinea pig and/or human patch sensitizationdata. When the MLLNA results were compared to those data obtainedfrom currently used predictive tests (guinea pig, human patchtest), the MLLNA showed good agreement for moderate and strongsensitizers. However, the assay may be prone to the potentialconfounding effects of irritation (false positives), may beinsensitive to weak sensitizers, and may be influenced by vehicleselection.     

硫普罗宁注射液腘窝淋巴结试验研究

目的用小鼠腘窝淋巴结试验（Popliteal lymph node assay,PLNA）以及检测淋巴细胞表面分子（CD4＋/CD8＋）来评价硫普罗宁注射液的免疫毒性。方法将昆明种小鼠随机分为5组,每组12只,设阳性对照组（盐酸氯丙嗪20.83mg.kg-1BW）、阴性对照组（氯化钠注射液）和硫普罗宁注射液（3.33、13.33、53.33mg.kg-1BW）3个剂量组,采用小鼠腘窝淋巴结试验方法测定腘窝淋巴结重量及细胞指数,淋巴细胞亚群测定采用流式细胞技术法,观察不同剂量组与对照组的差别。结果小鼠分别给予不同剂量的硫普罗宁注射液后,PLN（腘窝淋巴结）重量指数、细胞指数未见统计学意义的改变,但随用药剂量的增大而表现为增加的趋势。CD4＋/CD8＋淋巴细胞的比例无明显变化。结论硫普罗宁注射液有引起小鼠淋巴结肿大、增殖细胞的趋势。     

A murine local lymph node assay for the identification of contact allergens

The development of an alternative predictive test for the identification of contact sensitizing chemicals is described. The method is based upon the fact that, following epicutaneous application, sensitizing chemicals initiate a primary immunological response in the draining lymph node(s) which is characterized by lymphocyte proliferation. Experimental conditions for the measurement in vitro of the induced lymph node cell proliferative response have been optimized. On the basis of the data presented a local lymph node assay was developed in which CBA/Ca strain mice were exposed daily, for 3 consecutive days, to various concentrations of the test chemical, or to vehicle alone, on the dorsum of the ear. Lymph node activation was measured subsequently as a function of increased node weight, the frequency of large pyroninophilic cells and lymphocyte proliferation in the presence or absence of an exogenous source of interleukin 2 (IL-2). The results of a validation study are reported in which 22 well-characterized sensitizing chemicals of varying potency were examined. With the exception of three chemicals where water was used as the application vehicle, positive responses, defined as a substantial increase in lymphocyte proliferative activity, were recorded with all these test materials. Under the conditions employed non-sensitizing chemicals, including non-sensitizing irritant chemicals, failed to influence the immunological status of the draining lymph node. Taken together, the data suggest that the local lymph node assay provides the basis for a rapid and cost-effective alternative to the currently available guinea pig predictive test methods. The local lymph node assay may be of particular value for the evaluation of coloured or irritant chemicals.     

The regulatory use of the Local Lymph Node Assay for the notification of new chemicals in Europe

The regulatory use of the Local Lymph Node Assay (LLNA) for new chemicals registration was monitored by screening the New Chemicals Database (NCD), which was managed by the former European Chemicals Bureau (ECB) at the European Commission Joint Research Centre (JRC). The NCD centralised information for chemicals notified after 1981, where toxicological information has been generated predominantly according to approved test methods. The database was searched to extract notifications for which the information for skin sensitisation labelling was based on results derived with the LLNA. The details of these records were extracted and pooled, and evaluated with regard to the extent of use of the LLNA over time, as well as for analysing the information retrieved on critical aspects of the procedure e.g. strain and amount of animals used, lymph node processing, solvent and doses selected, stimulation indices, and for assessing their level of compliance to the OECD Test Guideline 429. In addition the accuracy of the reduced LLNA when applied to new chemicals was investigated.     

Evaluating the sensitization potential of surfactants: integrating data from the local lymph node assay, guinea pig maximization test, and in vitro methods in a weight-of-evidence approach

An integral part of hazard and safety assessments is the estimation of a chemical's potential to cause skin sensitization. Currently, only animal tests (OECD 406 and 429) are accepted in a regulatory context. Nonanimal test methods are being developed and formally validated. In order to gain more insight into the responses induced by eight exemplary surfactants, a battery of in vivo and in vitro tests were conducted using the same batch of chemicals. In general, the surfactants were negative in the GPMT, KeratinoSens and hCLAT assays and none formed covalent adducts with test peptides. In contrast, all but one was positive in the LLNA. Most were rated as being irritants by the EpiSkin assay with the additional endpoint, IL1-alpha. The weight of evidence based on this comprehensive testing indicates that, with one exception, they are non-sensitizing skin irritants, confirming that the LLNA tends to overestimate the sensitization potential of surfactants. As results obtained from LLNAs are considered as the gold standard for the development of new nonanimal alternative test methods, results such as these highlight the necessity to carefully evaluate the applicability domains of test methods in order to develop reliable nonanimal alternative testing strategies for sensitization testing.     

Skin sensitization in chemical risk assessment: report of a WHO/IPCS international workshop focusing on dose-response assessment

An international workshop was held in 2006 to evaluate experimental techniques for hazard identification and hazard characterization of sensitizing agents in terms of their ability to produce data, including dose-response information, to inform risk assessment. Human testing to identify skin sensitizers is discouraged for ethical reasons. Animal-free alternatives, such as quantitative structure-activity relationships and in vitro testing approaches, have not been sufficiently developed for such application. Guinea pig tests do not generally include dose-response assessment and are therefore not designed for the assessment of potency, defined as the relative ability of a chemical to induce sensitization in a previously naive individual. In contrast, the mouse local lymph node assay does include dose-response assessment and is appropriate for this purpose. Epidemiological evidence can be used only under certain circumstances for the evaluation of the sensitizing potency of chemicals, as it reflects degree of exposure as well as intrinsic potency. Nevertheless, human diagnostic patch test data and quantitative elicitation data have provided very important information in reducing allergic contact dermatitis risk and sensitization in the general population. It is therefore recommended that clinical data, particularly dose-response data derived from sensitized patients, be included in risk assessment.     

Comparison of BALB/c and CBA/J mice for the local lymph node assay using bromodeoxyuridine with flow cytometry (LLNA: BrdU-FCM)

The local lymph node assay using 5-bromo-2-deoxyuridine (BrdU) with flow cytometry (LLNA: BrdU-FCM) is a modified LLNA that is used to identify skin sensitizers by counting BrdU-incorporated lymph node cells (LNCs) with flow cytometry. Unlike other LLNA methods (OECD TG 429, 442A and 442B) in which the CBA/J mouse strain is used, LLNA: BrdU-FCM was originally designed to be compatible with BALB/c, a mouse strain that is more widely used in many countries. To justify the substitution of CBA/J for BALB/c, the equivalence of the test results between two strains shall be established prior to the official implementation of LLNA: BrdU-FCM. This study aims to compare the test results of LLNA: BrdU-FCM produced in BALB/c mice with those in CBA/J mice for 18 reference substances, including 13 sensitizers and 5 non-sensitizers, listed in OECD Test Guideline 429. Based on the LLNA: BrdU-FCM test procedure, we selected an appropriate solvent and then performed preliminary tests to determine the non-irritating dose ranges for the main study, which revealed the difference in the irritation responses to 8 of the 18 chemicals between the two strains. In the main study, we measured the changes in the number of total LNCs, which indicated differences in the responses to test chemicals between the two strains. However, the stimulation index obtained with the counts of BrdU-incorporated LNCs with 7-AAD using flow cytometry yielded comparable results and 100% concordance between the BALB/c and CBA/J mouse strains was achieved, suggesting that the performance of LLNA: BrdU-FCM using BALB/c mice was equivalent to that with CBA/J mice.     

ICCVAM Evaluation of the Murine Local Lymph Node Assay: I. The ICCVAM Review Process

New test methods are being developed to improve the prediction of human and environmental risks and to benefit animal welfare by reducing, refining, and replacing animal use. Regulatory adoption of new test methods is often a complex and protracted process, requiring test method validation, regulatory acceptance, and implementation. Assessments of new test methods have not always been uniform within or among regulatory agencies. Thus, there have been increased pressures for a harmonized approach to test method evaluation and acceptance. In 1997, in response to these pressures and to U.S. Public Law 103-43, the National Institute of Environmental Health Sciences (NIEHS) established the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) to coordinate interagency consideration of new and revised test methods. This article describes the validation and acceptance criteria and process used for the first test method evaluated by ICCVAM, the murine local lymph node assay (LLNA). Based on ICCVAM's conclusions and recommendations, the LLNA has been accepted by U.S. regulatory agencies as a stand-alone assay for allergic contact dermatitis. Two related articles in this series of three present the results of the independent peer review evaluation of the LLNA and summarize the performance characteristics of the database substantiating the validity of the LLNA.     

Skin sensitization testing in potency and risk assessment.

The purpose of this article is to review, and make recommendations for, the use of relevant skin sensitization test methods, for the purposes of determination of relative potency and the threshold dose necessary for the induction of skin sensitization, and for risk assessment. In addressing the first area, the utility of three guinea pig tests (the guinea pig maximization test, the occluded patch test, and the open epicutaneous test) of the local lymph node assay (LLNA) and of human volunteer testing for the assessment of relative potency and identification of thresholds for sensitization were considered. The following conclusions were drawn. (1) Although attempts have been made to modify the guinea pig maximization test for the purposes of deriving dose-response relationships, this method is usually unsuitable for determination of relative sensitizing potency. (2) Guinea pig methods that do not require the use of adjuvant and which employ a relevant route of exposure (the occluded patch test and the open epicutaneous test) are more appropriate for the assessment of relative skin-sensitizing potency. (3) The LLNA is suitable for the determination of relative skin sensitizing potency, and the adaptation of this method for derivation of comparative criteria such as EC3 values (the estimated concentration of test chemical required to induce a stimulation index of 3 in the LLNA) provides an effective and quantitative basis for such measurements. (4) For all the methods identified above, potency is assessed relative to other chemical allergens of known skin sensitizing potential. The estimation of likely threshold concentrations is dependent upon the availability of suitable benchmark chemicals of known potency for human sensitization. (5) Human testing (and specifically, the Human Repeat Insult Patch Test) can provide information of value in confirming the absence of skin sensitizing activity of formulations and products under specific conditions of use and exposure. Based on the above, the following recommendations are made. (1) If results are already available from suitable guinea pig tests, then judicious interpretation of the data may provide information of value in assessing relative skin sensitizing potency. This option should be explored before other analyses are conducted. (2) The LLNA is the recommended method for new assessments of relative potency, and/or for the investigation of the influence of vehicle or formulation on skin sensitizing potency. (3) Whenever available, human skin sensitization data should be incorporated into an assessment of relative potency. With respect to risk assessment, the conclusion drawn is that all the available data on skin-sensitizing activity in animals and man should be integrated into the risk-assessment process. Appropriate interpretation of existing data from suitable guinea pig studies can provide valuable information with respect to potency, as the first step in the development of a risk assessment. However, for de novo investigations, the LLNA is the method favored for providing quantitative estimations of skin-sensitizing potency that are best suited to the risk assessment process. Finally, human testing is of value in the risk assessment process, but is performed only for the purposes of confirming product safety.     

Evaluation of radioisotopic and non-radioisotopic versions of local lymph node assays for subcategorization of skin sensitizers compliant to UN GHS rev 4

Recently UN GHS has introduced the sub-categorization of skin sensitizers for which ECt (concentration estimated to induce stimulation index above threshold) of the murine local lymph node assay (LLNA) is used as criteria. Non-radioisotopic variants of LLNA, LLNA: DA, LLNA: BrdU-ELISA, LNCC and LLNA: BrdU-FCM were developed yet their utilities for potency sub-categorization are not established. Here we assessed the agreement of LLNA variants with LLNA or human data in potency sub-categorization for 22 reference substances of OECD TG429. Concordance of sub-categorization with LLNA was highest for LLNA: BrdU-FCM(91%, κ = 0.833, weighted kappa) followed by LLNA: BrdU-ELISA (82%, κ = 0.744) and LLNA: DA (73%, κ = 0.656) whereas LNCC only showed a modest association (64%, κ = 0.441). With human data, LLNA agreed best (77%) followed by LLNA: DA and LLNA: BrdU-FCM(73%), LLNA: BrdU-ELISA (68%) and LNCC(55%). Bland-Altman plot revealed that ECt's of LLNA variants largely agreed with LLNA where most values fell within 95% limit of agreement. Correlation between ECt's of LLNA and LLNA variants were high except for LNCC(pair-wise with LLNA, LLNA: DA, r = 0.848, LLNA: BrdU-ELISA, r = 0.744, LLNA: BrdU-FCM, r=0.786, and LNCC, r = 0.561 by Pearson). Collectively, these results demonstrated that LLNA variants exhibit performance comparable to LLNA in the potency sub-categorization although additional substances shall be analyzed in the future.     

Classification of contact allergens according to potency: proposals

It is clear that contact allergens vary substantially with regard to the relative potency with which they are able to induce skin sensitisation. Considerations of potency will in the future become a significant factor in the classification of skin sensitising chemicals. It is therefore appropriate to establish what is known of potency and thresholds in the induction of skin sensitisation and the elicitation of allergic contact dermatitis, and to identify approaches that might be available for assessment of relative potency for the purposes of categorising chemical allergens. This paper was prepared by an ECETOC (European Centre for Ecotoxicology and Toxicology) Task Force that had the objective of recommending approaches for the measurement of potency and definition of thresholds for both the induction and elicitation of contact sensitisation. The deliberations recorded here build upon recommendations made previously by an ECETOC Task Force that considered the conduct of standard skin sensitisation test methods for the purposes of hazard identification and risk assessment (ECETOC, Monograph No. 29, Brussels, 2000). The emphasis in this present paper is also on standard and accepted methods for the assessment of skin sensitisation, and for which OECD guidelines are available: the local lymph node assay (LLNA), the guinea pig maximisation test and the occluded patch test of Buehler. For various reasons, discussed in detail herein, attention focused primarily upon consideration of categorisation of chemical allergens and the identification of thresholds with respect to the induction of skin sensitisation, rather than the elicitation of allergic contact dermatitis. It is concluded that although the LLNA is the method of choice for the determination of skin sensitisation potency for the purposes of categorisation, if data are already available from appropriate guinea pig tests then their judicious interpretation may provide information of value in determinations of potency and categorisation. Included here are detailed and specific recommendations for how best the results of the three test methods considered can be used for the categorisation of chemical allergens as a function of skin sensitisation potency.     

ICCVAM Evaluation of the Murine Local Lymph Node Assay: III. Data Analyses Completed by the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods

To evaluate the reliability of the murine local lymph node assay (LLNA), a test for allergic contact dermatitis activity, the inter- and intralaboratory consistency statistics (h and k, respectively) were calculated for validation studies testing multiple chemicals. The analysis indicated the absence of excessive variability in the dose calculated to induce a threefold or greater increase in the stimulation index (SI). To assess the appropriateness of using an SI of 3 as the decision criteria for identifying a sensitizing compound, LLNA results based on SI values of 2.0, 2.5, 3.0, 3.5, and 4.0 were compared with guinea pig or human results. The results supported the use of an SI of 3 as the decision criteria. Assay performance was determined by comparing LLNA results to results obtained for guinea pigs or humans. The accuracy of the LLNA was 89% when compared with results from the guinea pig maximization test (GPMT)/Buehler assay (BA). The performance of the LLNA and the GPMT/BA was similar when each was compared to human maximization test results plus substances included as human patch test allergens. The LLNA offered advantages over the GPMT in respect to both the time required to conduct the test and the assay cost.     

ICCVAM Evaluation of the Murine Local Lymph Node Assay: II. Conclusions and Recommendations of an Independent Scientific Peer Review Panel

The validation status of the murine local lymph node assay (LLNA), a method for assessing the allergic contact dermatitis potential of chemicals, was evaluated by an independent peer review panel (Panel) convened by the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM). The LLNA measures lymphocyte proliferation using incorporation of radioactive thymidine or iododeoxyuridine into cells of the draining lymph nodes of mice topically exposed to a test article. The Panel concluded that the assay performed as well as currently accepted guinea pig methods [guinea pig maximization test (GPMT)/Buehler assay (BA)] for the hazard identification of strong to moderate chemical sensitizing agents, but that it might not correctly identify all weak sensitizers or metals (potential false negative response) or all strong irritants (potential false positive response). The Panel concluded also that the LLNA involves less pain and distress than conventional guinea pig methods. The Panel unanimously recommended the LLNA as a stand-alone alternative for contact sensitization hazard assessment, provided that certain protocol modifications were made. These included collection of individual, rather than pooled, animal response data; the inclusion of a concurrent positive control; and consideration of dose–response information and statistical analyses. A standardized LLNA protocol is provided.     

Safety assessment of allergic contact dermatitis hazards: an analysis supporting reduced animal use for the murine local lymph node assay

The original Organisation for Economic Co-operation and Development Test Guideline 429 (OECD TG 429) for the murine local lymph node assay (LLNA) required five mice/group if mice were processed individually. We used data from 83 LLNA tests (275 treated groups) to determine the impact on the LLNA outcome of reducing the group size from five to four. From DPM measurements, we formed all possible four- and five-mice combinations for the treated and control groups. Stimulation index (SI) values from each four-mice combination were compared with those from five-mice combinations, and agreement (both SI<3 or both SI ≥ 3) determined. Average agreement between group sizes was 97.5% for the 275 treated groups. Compared test-by-test, 90% (75/83) of the tests had 100% agreement; agreement was 83% for the remaining eight tests. Disagreement was due primarily to variability in animal responses and closeness of the SI to three (positive response threshold) rather than to group size reduction. We conclude that using four rather than five mice per group would reduce animal use by 20% without adversely impacting LLNA performance. This analysis supported the recent update to OECD TG 429 allowing a minimum of four mice/group when each mouse is processed individually.     

Assessing the potency of respiratory allergens: uncertainties and challenges

In contrast to skin sensitisation, there are no accepted tests for the identification of chemicals or proteins with the potential to cause sensitisation of the respiratory tract. Although progress has been made, the assessment of respiratory sensitisation potential remains associated with significant challenges and uncertainties. Nevertheless, there is interest in determining whether it is possible to assess the relative potency of respiratory sensitisers. The second Adaptation to Technical Progress (ATP) to the EU Classification, Labelling and Packaging (CLP) Regulation recently introduced changes to criteria for classification and labelling of chemicals and preparations, bringing it in line with the 3rd revision to the UN Globally Harmonised System of Classification and Labelling of Chemicals (GHS). Among other things, the second ATP introduces sub-categories for respiratory and skin sensitisers, discriminating between strong sensitisers and other sensitisers. Here we examine whether such categorisation of protein and/or chemical respiratory allergens is realistic and/or feasible. For this purpose comparisons have been drawn with skin sensitisation, where potency categorisation has now been widely accepted and successfully integrated into the regulatory process. The conclusion drawn is that, on the basis of the currently available information, potency categorisation for respiratory sensitisers is premature and could potentially be misleading.     

Potency values from the local lymph node assay: Application to classification,labelling and risk assessment

Hundreds of chemicals are contact allergens but there remains a need to identify and characterise accurately skin sensitising hazards. The purpose of this review was fourfold. First, when using the local lymph node assay (LLNA), consider whether an exposure concentration (EC3 value) lower than 100% can be defined and used as a threshold criterion for classification and labelling. Second, is there any reason to revise the recommendation of a previous ECETOC Task Force regarding specific EC3 values used for sub-categorisation of substances based upon potency? Third, what recommendations can be made regarding classification and labelling of preparations under GHS? Finally, consider how to integrate LLNA data into risk assessment and provide a rationale for using concentration responses and corresponding no-effect concentrations. Although skin sensitising chemicals having high EC3 values may represent only relatively low risks to humans, it is not possible currently to define an EC3 value below 100% that would serve as an appropriate threshold for classification and labelling. The conclusion drawn from reviewing the use of distinct categories for characterising contact allergens was that the most appropriate, science-based classification of contact allergens according to potency is one in which four sub-categories are identified: ‘extreme’, ‘strong’, ‘moderate’ and ‘weak’. Since draining lymph node cell proliferation is related causally and quantitatively to potency, LLNA EC3 values are recommended for determination of a no expected sensitisation induction level that represents the first step in quantitative risk assessment.     

Neutralizing Concentrations of Anti-Botulinum Toxin Antibodies Positively Correlate with Mouse Neutralization Assay Results in a Guinea Pig Model

Botulinum neurotoxins (BoNT) are some of the most toxic proteins known and can induce respiratory failure requiring long-term intensive care. Treatment of botulism includes the administration of antitoxins. Monoclonal antibodies (mAbs) hold considerable promise as BoNT therapeutics and prophylactics, due to their potency and safety. A three-mAb combination has been developed that specifically neutralizes BoNT serotype A (BoNT/A), and a separate three mAb combination has been developed that specifically neutralizes BoNT serotype B (BoNT/B). A six mAb cocktail, designated G03-52-01, has been developed that combines the anti-BoNT/A and anti-BoNT/B mAbs. The pharmacokinetics and neutralizing antibody concentration (NAC) of G03-52-01 has been determined in guinea pigs, and these parameters were correlated with protection against an inhalation challenge of BoNT/A1 or BoNT/B1. Previously, it was shown that each antibody demonstrated a dose-dependent mAb serum concentration and reached maximum circulating concentrations within 48 h after intramuscular (IM) or intraperitoneal (IP) injection and that a single IM injection of G03-52-01 administered 48 h pre-exposure protected guinea pigs against an inhalation challenge of up to 93 LD₅₀s of BoNT/A1 and 116 LD₅₀s of BoNT/B1. The data presented here advance our understanding of the relationship of the neutralizing NAC to the measured circulating antibody concentration and provide additional support that a single IM or intravenous (IV) administration of G03-52-01 will provide pre-exposure prophylaxis against botulism from an aerosol exposure of BoNT/A and BoNT/B.     

MTT比色法与相对增殖度法对输液用包装材料的细胞毒性检测结果的比较

目的 比较四唑盐(MTT)比色法和相对增殖度法对4种输液用包装材料细胞毒性检查结果的相关性,评价2种方法在检测药包材体外细胞毒性作用上的优缺点。为建立快速有效的药包材检测新标准提供有力依据。方法 L-929细胞分别采用MTT法和细胞增殖度法对4种包装材料的浸提液进行细胞毒性研究,比较材料对细胞的毒性等级,算出细胞的相对增殖度,分析比较2种方法相关性。结果 在同样实验条件下,4种药品包材表现出对L-929细胞不同的细胞毒性。与细胞增殖度法比较,MTT法与细胞增殖法检测结果具有很好的相关性r=0.966(P<0.05)。结论 与相对增殖度法相比,MTT比色法由于实际检测所需的细胞量相对较少、试验步骤相对简便、检测周期短,因此具有一定的优越性,值得推荐作为细胞毒性检测方法。