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PubMed2004

Copper hypersensitivity: dermatologic aspects.

Reports of immune reactions of both the immediate and delayed types due to cutaneous or systemic exposure to copper have been reviewed, in the endeavor to draw a comprehensive profile of the immunogenic potential of that metal and its compounds. The metal's immunotoxic potential is also briefly reviewed. In principle, as noted for other transition metals, the electropositive copper ion is potentially immunogenic due to its ability to diffuse through biological membranes to form complexes in contact with tissue protein. Based on predictive guinea pig test and the local lymph node assay (LLNA), copper has a low sensitization potential. Reports of immune reactions to copper include immunologic contact urticaria (ICU), allergic contact dermatitis (ACD), systemic allergic reactions (SAR) and contact stomatitis (STO), but considering the widespread use of copper IUDs and the importance of copper in coinage, items of personal adornment and industry, unambiguous reports of sensitization to the metal are extremely rare, and even fewer are the cases, which appear clinically relevant. Reports of immune reactions to copper mainly describe systemic exposure from intrauterine devices and prosthetic materials in dentistry, implicitly excluding induction of the hypersensitivity from contact with the skin as a risk factor. We provide a diagnostic algorithm that might clarify the frequency of copper hypersensitivity.

Copper↗

PubMed1994

Contact sensitivity to Tinuvin P in mice.

The contact sensitizing potential of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (Tinuvin P) was investigated using the murine local lymph node assay (LLNA) and the mouse ear swelling test with some modification in the induction procedure (modified MEST). Topical exposure of the ears to Tinuvin P in acetone:olive oil (AOO) for 3 consecutive days induced no increase in auricular lymph node weight and lymph node cell proliferation. In the LLNA, Tinuvin P was negative, and its sensitizing potential was determined as not strong. In the modified MEST, mice were sensitized with a combination of an intradermal injection of 0.2% Tinuvin P in Freund's complete adjuvant into the shaved abdomen and topical application of 1% Tinuvin P in AOO on both ears for 3 consecutive days. The ear thickness in mice previously treated with Tinuvin P increased significantly on challenge with Tinuvin P. A cross-reaction test between Tinuvin P and various substituted benzotriazole ultraviolet light (UV) absorbers was performed. Challenge with these benzotriazole compounds on the ears of the mice previously sensitized to Tinuvin P showed no increase in ear thickness. These data indicated that Tinuvin P had a contact sensitizing ability, while Tinuvin P-sensitized mice did not cross-react with the other benzotriazole UV absorbers.

Animals↗

PubMed1996

Dichloronitrobenzene: a reappraisal of its skin sensitization potential.

Unlike the closely related chemical dinitrochlorobenzene (DNCB), which is a very strong contact allergen, dichloronitrobenzene (DCNB) has been widely regarded as a non-allergen and, as such, a useful control for its strongly sensitizing counterpart. Nevertheless, it is still an organic chemical species readily capable of penetrating skin and, rather than being regarded as completely inert, it has even been suggested to react with the immune system in such a way that it induces specific tolerance to its chemical structure. We investigated whether DCNB was in reality a non-allergen, or rather merely a weak contact sensitizer. In both a rigorously conducted guinea pig maximization test and in a modified murine local lymph node assay, DCNB was demonstrated to possess weak sensitizing activity. On this basis, DCNB cannot be regarded as inert with respect to contact allergic potential, and is therefore inappropriate as a negative control in studies of skin sensitization.

Animals↗

PubMed1999

Skin sensitization risk assessment: a comparative evaluation of 3 isothiazolinone biocides.

Many of the chemicals in common use possess, to some degree, a capacity to cause skin sensitization. Consequently, it is important to conduct a thorough and accurate risk assessment when it can be anticipated that such chemicals are likely to come into contact with human skin. Such risk assessments must consider the nature and extent of dermal exposure together with the sensitizing potency of the chemical. Whilst the exposure elements of the risk assessment process are often well understood, or can at least be reasonably predicted on the basis of the proposed usage of the chemical, the determination of skin sensitizing potency may be problematic. In this paper, we describe an approach to the determination of relative potency of 3 isothiazolinone biocides. Initially, the local lymph node assay (LLNA) provides an estimate of relative sensitizing potency. Where appropriate, this can be followed by confirmatory testing in the human repeat insult patch test (HRIPT). The data generated reveal that (chloro)methyl isothiazolinone (CMI) is a significantly stronger sensitizer than either methyl trimethylene isothiazolinone (MTI) or benzisothiazolinone (BIT). Furthermore, both the LLNA and the HRIPT data show consistently that BIT is a somewhat weaker skin sensitizer than MTI. As an important additional component of the safety evaluation, the ability of these sensitizing isothiazolinones to cross-react has been considered; the data indicate that the more weakly sensitizing isothiazolinones do not elicit allergic reactions in subjects sensitized to MCI. The implications for use of these biocides in various product types are discussed.

Adolescent↗

PubMed1999

Sensitizing potential in mice, guinea pig and man of the preservative Euxyl K 400 and its ingredient methyldibromo glutaronitrile.

The allergenicity of the preservative Euxyl K 400 and its principal allergen methyldibromo glutaronitrile (MDBGN) (1,2-dibromo-2,4-dicyanobutane) was investigated using 3 animal models; in mice, the local lymph node assay (LLNA) and in guinea pigs, the guinea pig maximization test (GPMT) and the cumulative contact enhancement test (CCET) with a dose-response protocol included. Previous attempts to define the sensitization capacity of these chemicals have given conflicting results. For comparison, the frequency and causes of positive patch test reactions to Euxyl K 400 and MDBGN were studied in patients referred to an occupational dermatology clinic. This investigation showed that Euxyl K 400 and MDBGN can give rise to contact allergy in man and that the relevant cases found mainly had similar exposure as non-occupational cases. A contact allergenic potential could be detected for MDBGN in 2 animal models, i.e., the CCET and the LLNA, and also for Euxyl K 400 in the LLNA. However, statistical analysis of the results from the GPMT with MDBGN failed to detect the sensitizing potential of this particular allergen. The results indicate that to be able to detect the allergenic potential of Euxyl K 400 and MDBGN, a predictive test method with multiple topical applications at induction is required. It is therefore important that an investigator is aware of the possibility of using various predictive test models for investigation of potential contact allergens.

Allergens↗

PubMed2007

Information derived from sensitization test methods: test sensitivity, false positives and false negatives.

Predictive toxicology tests for the prospective identification of skin-sensitizing chemicals are well known and have been used for many years. However, of these, only the local lymph node assay (LLNA) has actually undergone formal independent assessment to determine the accuracy of the predictions, particularly with respect to the likelihood of false positives and false negatives. Often, efforts to increase the sensitivity of a test (reducing false negatives) tend to increase the number of false positives. In this short review, these issues are discussed in particular relation to the 3 predictive tests available in regulatory toxicology, the guinea-pig maximization test, the occluded patch test of Buehler and the LLNA. A key perspective is that no predictive test is without limitations; having a good appreciation of these limitations is necessary for making the best use of the information derived from these methods.

Animals↗

PubMedDate not supplied

Copper hypersensitivity: dermatologic aspects--an overview.

Reports of immune hypersensitivity reactions of both the immediate and the delayed type following cutaneous or systemic exposure to copper are reviewed here in an endeavor to draw a comprehensive profile of the immunogenic potential of that metal and its compounds. The immunotoxic potential of the metal is also briefly reviewed. In principle, as noted for other transition metals, the electropositive copper ion is potentially immunogenic because of its ability to diffuse through biological membranes, forming complexes when in contact with tissue protein. Based on the results of the predictive guinea pig test and the local lymph node assay (LLNA), copper has a low sensitization potential. Reports of immune reactions to copper include immunologic contact urticaria (ICU), allergic contact dermatitis (ACD), systemic allergic reactions (SAR) and contact stomatitis (STO), but considering the widespread use of copper intrauterine devices (IUDs) and the importance of copper in coinage, items of personal adornment and industry, unambiguous reports of sensitization to the metal are extremely rare, and even fewer are the cases that appear clinically relevant. Most reports of immune reactions to copper describe systemic exposure as a cause--predominantly to intrauterine devices and to prosthetic materials in dentistry--implicitly excluding the induction of hypersensitivity from contact with the skin as a risk factor.

Animals↗

PubMed1998

Contact hypersensitivity to dicyclohexylcarbodiimide and diisopropylcarbodiimide in female B6C3F1 mice.

Dicyclohexylcarbodiimide (DCC) and diisopropylcarbodiimide (DIC) are two commonly used coupling reagents in protein synthesis resulting in exposure of individuals in chemical and pharmaceutical industries as well as research laboratories involved in protein synthesis and recombinant DNA techniques. The objectives of these studies were to determine the irritation and sensitizing potential of these two compounds when applied topically to B6C3F1 mice. Sensitization potential was assessed by the Mouse Ear Swelling Test (MEST) and the murine Local Lymph Node Assay (LLNA). Concentrations used in the contact hypersensitivity assays were determined by primary irritancy studies. DCC and DIC were identified as both irritants and contact sensitizers with the MEST being a more sensitive indicator of sensitization potential. The MEST identified DCC as a sensitizer at concentrations as low as 0.006% (w/v) 24 hr and 48 hr post challenge and DIC at 0.3% (w/v) and 1.5% (w/v) 24 and 48 hr post challenge, respectively. In the LLNA, the lowest concentrations yielding a significant response were 0.06% (w/v) for DCC and 10% (w/v) for DIC.

Administration, Topical↗

PubMedDate not supplied

Reduction, refinement and replacement: putting the immune system to work.

Many chemicals are known to be, or have been implicated as, contact allergens, and allergic contact dermatitis is an important occupational and environmental health issue. It is the responsibility of toxicologists to identify those chemicals that have the potential to induce skin sensitisation, and to assess the conditions under which there will exist a risk to human health. This article describes progress that has been made in the development of new approaches to the toxicological evaluation of skin sensitisation, and the benefits to animal welfare that such developments have already produced, and are likely to produce in the future. In this context, the local lymph node assay is described with regard to hazard identification and risk assessment, and possible strategies for the development of in vitro approaches to safety assessment are discussed.

Allergens↗

PubMed2003

Safety assessment of Salicylic Acid, Butyloctyl Salicylate, Calcium Salicylate, C12-15 Alkyl Salicylate, Capryloyl Salicylic Acid, Hexyldodecyl Salicylate, Isocetyl Salicylate, Isodecyl Salicylate, Magnesium Salicylate, MEA-Salicylate, Ethylhexyl Salicylate, Potassium Salicylate, Methyl Salicylate, Myristyl Salicylate, Sodium Salicylate, TEA-Salicylate, and Tridecyl Salicylate.

Salicylic Acid is an aromatic acid used in cosmetic formulations as a denaturant, hair-conditioning agent, and skin-conditioning agent--miscellaneous in a wide range of cosmetic products at concentrations ranging from 0.0008% to 3%. The Calcium, Magnesium, and MEA salts are preservatives, and Potassium Salicylate is a cosmetic biocide and preservative, not currently in use. Sodium Salicylate is used as a denaturant and preservative (0.09% to 2%). The TEA salt of Salicylic Acid is used as an ultraviolet (UV) light absorber (0.0001% to 0.75%). Several Salicylic Acid esters are used as skin conditioning agents--miscellaneous (Capryloyl, 0.1% to 1%; C12-15 Alkyl, no current use; Isocetyl, 3% to 5%; Isodecyl, no current use; and Tridecyl, no current use). Butyloctyl Salicylate (0.5% to 5%) and Hexyldodecyl Salicylate (no current use) are hair-conditioning agents and skin-conditioning agents--miscellaneous. Ethylhexyl Salicylate (formerly known as Octyl Salicylate) is used as a fragrance ingredient, sunscreen agent, and UV light absorber (0.001% to 8%), and Methyl Salicylate is used as a denaturant and flavoring agent (0.0001% to 0.6%). Myristyl Salicylate has no reported function. Isodecyl Salicylate is used in three formulations, but no concentration of use information was reported. Salicylates are absorbed percutaneously. Around 10% of applied salicylates can remain in the skin. Salicylic Acid is reported to enhance percutaneous penetration of some agents (e.g., vitamin A), but not others (e.g., hydrocortisone). Little acute toxicity (LD(50) in rats; >2 g/kg) via a dermal exposure route is seen for Salicylic Acid, Methyl Salicylate, Tridecyl Salicylate, and Butyloctyl Salicylate. Short-term oral, inhalation, and parenteral exposures to salicylates sufficient to produce high blood concentrations are associated primarily with liver and kidney damage. Subchronic dermal exposures to undiluted Methyl Salicylate were associated with kidney damage. Chronic oral exposure to Methyl Salicylate produced bone lesions as a function of the level of exposure in 2-year rat studies; liver damage was seen in dogs exposed to 0.15 g/kg/day in one study; kidney and liver weight increases in another study at the same exposure; but no liver or kidney abnormalities in a study at 0.167 g/kg/day. Applications of Isodecyl, Tridecyl, and Butyloctyl Salicylate were not irritating to rabbit skin, whereas undiluted Ethylhexyl Salicylate produced minimal to mild irritation. Methyl Salicylate at a 1% concentration with a 70% ethanol vehicle were irritating, whereas a 6% concentration in polyethylene glycol produced little or no irritation. Isodecyl Salicylate, Methyl Salicylate, Ethylhexyl (Octyl) Salicylate, Tridecyl Salicylate, and Butyloctyl Salicylate were not ocular irritants. Although Salicylic Acid at a concentration of 20% in acetone was positive in the local lymph node assay, a concentration of 20% in acetone/olive oil was not. Methyl Salicylate was negative at concentrations up to 25% in this assay, independent of vehicle. Maximization tests of Methyl Salicylate, Ethylhexyl Salicylate, and Butyloctyl Salicylate produced no sensitization in guinea pigs. Neither Salicylic Acid nor Tridecyl Salicylate were photosensitizers. Salicylic Acid, produced when aspirin is rapidly hydrolyzed after absorption from the gut, was reported to be the causative agent in aspirin teratogenesis in animals. Dermal exposures to Methyl Salicylate, oral exposures to Salicylic Acid, Sodium Salicylate, and Methyl Salicylate, and parenteral exposures to Salicylic Acid, Sodium Salicylate, and Methyl Salicylate are all associated with reproductive and developmental toxicity as a function of blood levels reached as a result of exposure. An exposure assessment of a representative cosmetic product used on a daily basis estimated that the exposure from the cosmetic product would be only 20% of the level seen with ingestion of a "baby" aspirin (81 mg) on a daily basis. Studies of the genotoxic potential of Salicylic Acid, Sodium Salicylate, Isodecyl Salicylate, Methyl Salicylate, cosmetic product would be only 20% of the level seen with ingestion of a "baby" aspirin (81 mg) on a daily basis. Studies of the genotoxic potential of Salicylic Acid, Sodium Salicylate, Isodecyl Salicylate, Methyl Salicylate, Ethylhexyl (Octyl) Salicylate, Tridecyl Salicylate, and Butyloctyl Salicylate were generally negative. Methyl Salicylate, in a mouse skin-painting study, did not induce neoplasms. Likewise, Methyl Salicylate was negative in a mouse pulmonary tumor system. In clinical tests, Salicylic Acid (2%) produced minimal cumulative irritation and slight or no irritation(1.5%); TEA-Salicylate (8%) produced no irritation; Methyl Salicylate (>12%) produced pain and erythema, a 1% aerosol produced erythema, but an 8% solution was not irritating; Ethylhexyl Salicylate (4%) and undiluted Tridecyl Salicylate produced no irritation. In atopic patients, Methyl Salicylate caused irritation as a function of concentration (no irritation at concentrations of 15% or less). In normal skin, Salicylic Acid, Methyl Salicylate, and Ethylhexyl (Octyl) Salicylate are not sensitizers. Salicylic Acid is not a photosensitizer, nor is it phototoxic. Salicylic Acid and Ethylhexyl Salicylate are low-level photoprotective agents. Salicylic Acid is well-documented to have keratolytic action on normal human skin. Because of the possible use of these ingredients as exfoliating agents, a concern exists that repeated use may effectively increase exposure of the dermis and epidermis to UV radiation. It was concluded that the prudent course of action would be to advise the cosmetics industry that there is a risk of increased UV radiation damage with the use of any exfoliant, including Salicylic Acid and the listed salicylates, and that steps need to be taken to formulate cosmetic products with these ingredients as exfoliating agents so as not to increase sun sensitivity, or when increased sun sensitivity would be expected, to include directions for the daily use of sun protection. The available data were not sufficient to establish a limit on concentration of these ingredients, or to identify the minimum pH of formulations containing these ingredients, such that no skin irritation would occur, but it was recognized that it is possible to formulate cosmetic products in a way such that significant irritation would not be likely, and it was concluded that the cosmetics industry should formulate products containing these ingredients so as to be nonirritating. Although simultaneous use of several products containing Salicylic Acid could produce exposures greater than would be seen with use of baby aspirin (an exposure generally considered to not present a reproductive or developmental toxicity risk), it was not considered likely that consumers would simultaneously use multiple cosmetic products containing Salicylic Acid. Based on the available information, the Cosmetic Ingredient Review Expert Panel reached the conclusion that these ingredients are safe as used when formulated to avoid skin irritation and when formulated to avoid increasing the skin's sun sensitivity, or, when increased sun sensitivity would be expected, directions for use include the daily use of sun protection.

Administration, Inhalation↗

PubMed2004

Toxicity studies on western juniper oil (Juniperus occidentalis) and Port-Orford-cedar oil (Chamaecyparis lawsoniana) extracts utilizing local lymph node and acute dermal irritation assays.

The essential oil extracts of western juniper oil (Juniperus occidentalis) and Port-Orford-cedar oil (Chamaecyparis lawsoniana) were evaluated for possible dermal toxic effects on mice and rabbits. Mice were tested for their response to both extracts utilizing a local lymph node assay. Western juniper oil extract at 0.5% and 5% concentrations did not show a stimulation index (SI) greater than normal (3.0); however, a 50% concentration did show a positive response at 3.3. Port-Orford-cedar oil extract did not show a positive response at concentrations of 0.5%, 5% or 50%. An acute dermal irritation study using rabbits had a primary irritation index (PII) of 3.3 with 100% Port-Orford-cedar oil extract. This was reduced to a PII of 0.625 when diluted 1:1 with olive oil. Undiluted western juniper oil extract had a PII score of 2.7. While a 5.0% solution had a PII score of 0.3, a 0.5% solution of western juniper oil was a non-irritant. It would appear that animals bedded on wood shavings have contact with essential oils at concentrations far less than the 2% maximum by weight obtained by steam distillation extraction. These concentrations did not elicit a hypersensitivity response.

Animals↗

PubMed2003

Tritiated thymidine incorporation does not enhance sensitivity of the popliteal lymph node assay.

The popliteal lymph node (PLN) assay has been proposed as a tool to predict drugs and chemicals with the potential to induce systemic autoimmune reactions in man. In this assay, weight and cellularity indices typically are the measured endpoints. The present study was conducted to test whether incorporation of tritiated thymidine could improve sensitivity of the PLN assay. Male and female Balb/c mice were injected with 20 microCi of [3H]-methyl-thymidine intravenously 7 days after receiving 0.5, 1 or 2 mg of diphenylhydantoin, streptozotocin, sulfamethoxazole, ofloxacin, phenobarbital, or metformin intradermally. Results obtained with incorporation of tritiated thymidine were compared to weight indices. No consistent or marked differences in these endpoints were noted whatever the compound used. This study shows that incorporation of tritiated thymidine does not improve sensitivity of the PLN assay.

Animals↗

PubMed2001

Blockade of collagen-induced arthritis post-onset by antibody to granulocyte-macrophage colony-stimulating factor (GM-CSF): requirement for GM-CSF in the effector phase of disease.

There is mounting evidence for a role of the growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF) in inflammatory disease, including arthritis. In the present study, we examined the effectiveness of treatment of collagen-induced arthritis (CIA) with a neutralizing mAb to GM-CSF. DBA/1 mice were immunized for the development of CIA and treated at different times, and with different doses, with neutralizing mAb to GM-CSF or isotype control mAb. Anti-GM-CSF mAb treatment prior to the onset of arthritis, at the time of antigen challenge, was effective at ameliorating the ensuing disease. Modulation of arthritis was seen predominantly as a reduction in overall disease severity, both in terms of the number of limbs affected per mouse and the clinical score of affected limbs. Importantly, anti-GM-CSF mAb treatment ameliorated existing disease, seen both as a reduction in the number of initially affected limbs progressing and lower numbers of additional limbs becoming affected. By histology, both inflammation and cartilage destruction were reduced in anti-GM-CSF-treated mice, and the levels of tumor necrosis factor-a and IL-1beta were also reduced in joint tissue washouts of these mice. Neither humoral nor cellular immunity to type II collagen, however, was affected by anti-GM-CSF mAb treatment. These results suggest that the major effect of GM-CSF in CIA is on mediating the effector phase of the inflammatory reaction to type II collagen. The results also highlight the essential role of GM-CSF in the ongoing development of inflammation and arthritis in CIA, with possible therapeutic implications for rheumatoid arthritis.

Animals↗

PubMed2007

Popliteal lymph node (PLN) assay to study adjuvant effects on respiratory allergy.

Different variants of the popliteal lymph node (PLN) assay have been published. Here we describe the adjuvant popliteal lymph node assay, an immune response assay to study the adjuvant activity of soluble substances as well as particulate matter. The substance to be studied for adjuvant activity is injected into the hind footpad of mice or rats together with an antigen. Adjuvant activity is determined as the increase in PLN weight and cell numbers in animals receiving antigen together with the substance under study, compared with PLN weight and cell numbers in animals given the antigen without the substance in question, and animals given the putative adjuvant alone. Because lymph node weight and cell numbers are immunologically non-specific parameters, specific immune response assays like serum antibody responses or antibody-forming cell numbers should additionally be performed. Different antigens and immune response assays may be used, depending on the research question asked. In relation to respiratory (or food) allergy, the assays should as a minimum include determination of specific IgE in serum, and preferably also IgG1 (mouse). Serum specific IgG2a antibody determination may be added to get an indication of the Th1-Th2-balance of the response. The adjuvant PLN assay, with cellular response assays performed in the draining popliteal lymph node and antibody determinations in serum, requires small amounts of test material. The assay offers a practical, sensitive and reproducible method to determine the adjuvant activity of soluble substances as well as particulate material, with the possibility to also perform mechanistic studies.

Adjuvants, Immunologic↗

PubMed2004

Evaluation of the use of reporter antigens in an auricular lymph node assay to assess the immunosensitizing potential of drugs.

Immune-mediated idiosyncratic drug reactions are a major problem for susceptible patients, physicians, and the pharmaceutical industry. Validated screening tools to assess the immunosensitizing capacity of orally or intravenously administered pharmaceuticals are currently not available. To date, the popliteal lymph node assay (PLNA) seems the most promising tool for this purpose. The PLNA has recently been extended with the use of reporter antigens (RA) that are coinjected together with the drug of interest. The measurement of isotypes of RA-specific antibody-secreting cells (ASC) enables the distinction of sensitizing chemicals and (nonsensitizing) irritants without radio-isotopic end points. However, the use of footpad injections raises ethical concerns. Therefore, we examined the use of RA after intradermal injection into the ear of BALB/c mice and measured RA-specific ASC in the draining auricular lymph node (ALN). We show that RA-specific IgG isotype ASC numbers are very useful and sensitive parameters to identify drug-induced hypersensitivity in both PLN and ALN. However, the type 1-associated parameters (CD8(+) cells, macrophages, IFN-gamma, TNF-alpha, and IL-1 beta) that are induced in the PLN by streptozotocin were less pronounced in the ALN. Thus, the PLNA may provide more immunologically relevant information on the mechanisms of certain chemical-induced hypersensitivity reactions. The RA-ALN assay may provide an alternative for the RA-PLNA; both assays can be used to distinguish sensitizing compounds from nonsensitizing ones.

Animals↗

PubMed2001

Positive responses to imipramine in the popliteal lymph node assay are due to primary irritation.

The popliteal lymph node (PLN) assay has long been proposed as a tool to detect immunotoxicants with the potential to induce systemic autoimmunity. A major problem hampering the further validation of this assay is the need to rule out irritants that cause false-positive PLN responses. The anti-depressant, imipramine, has not been reported to induce systemic autoimmune reactions in treated patients, but has been repeatedly found positive in the PLN assay, suggesting that this is a false-positive response. To test this hypothesis, the effects of imipramine were compared to those of 50% ethanol in C57B1/6 mice. Footpad edema was evidenced in the few days after injection of both ethanol and imipramine. T-cell depletion using monoclonal antibodies against either CD4+ or CD8+ T-lymphocytes prior to the PLN assay did not influence the responses to either ethanol or imipramine. Cytokine (TNFalpha, IL-1alpha, IL-1beta, IL-2R, IL-6, IL-12 and IFN-gamma) fingerprinting of the PLNs after injection of ethanol and imipramine evidenced the same pattern of responses. These results indicate a closely similar pattern of responses following the footpad injection of either imipramine or ethanol. The conclusion can be drawn that imipramine induces positive responses in the PLN assay via primary (nonspecific) irritation.

Animals↗

PubMedDate not supplied

Investigating the TNP-OVA and direct popliteal lymph node assays for the detection of immunostimulation by drugs associated with anaphylaxis in humans.

Using current animal models, it is not possible to identify low-molecular-weight compounds (LMWCs) that are likely to be associated with anaphylaxis. It is generally accepted that the ultimate effector mechanism involves drug-induced IgE antibody. The objective of the present study was to determine if diclofenac, zomepirac and glafenine, which are associated with anaphylaxis in humans, have immunostimulating potential in the murine TNP-OVA (trinitrophenyl-ovalbumin) popliteal lymph node assay (PLNA), and more specifically to determine if the immunostimulation caused by these LMWCs results in IgE antibody production. These LMWCs were chosen because both zomepirac and glafenine were removed from the market due to high association with anaphylaxis, and diclofenac, which remains on the market, is frequently associated with anaphylaxis. In addition to conducting a TNP-OVA PLNA, the immunostimulating potential of these compounds was examined in the direct PLNA. When co-administered with TNP-OVA, all three LMWCs caused dose-dependent (0.25, 0.50, 1.00 and 1.25 mg) increases in popliteal lymph node (PLN) weight and cellularity that were observed beginning with the 0.25-mg dose. In addition, beginning with the 0.25-mg dose, all three compounds caused dose-dependent increases in TNP-OVA specific IgM and IgG(1) antibody-forming cells (AFCs). Diclofenac induced an isotype switch and caused a dose-dependent increase in the number of IgE AFCs with no detectable IgG(2a) AFCs and minimal high-dose-only IgG(2b) AFCs. Zomepirac induced IgE, IgG(2a) and IgG(2b) AFCs following the injection of 0.50 mg only, and glafenine induced IgE, IgG(2a) and IgG(2b) AFCs following the injection of 0.50-1.00 mg. In the direct PLNA, diclofenac caused dose-dependent increases in PLN weight and cellularity that were observed beginning with dose of 0.50 mg, whereas zomepirac failed to increase any PLN parameter and glafenine only increased the PLN weight. These results suggest that diclofenac, zomepirac and glafenine are immunostimulating LMWCs in the TNP-OVA PLNA with the potential to induce IgE antibody against a co-administered hapten-conjugate. Furthermore, these results suggest that the TNP-OVA PLNA offered significant advantages over the direct PLNA. Although it is not realistic to suggest that a single assay, based on a low number of test compounds, can identify all LMWCs with the potential to cause anaphylaxis in humans, these observations do demonstrate the potential utility of the PLNAs in examining LMWC-induced immunomodulation and support further development and investigation of the assays.

Adjuvants, Immunologic↗

PubMed1990

1-Chloromethylpyrene: a reference skin sensitizer and genotoxin.

1-Chloromethylpyrene (1-CMP) has been evaluated as a model mutagen and toxin related to the ultimate electrophiles derived from benzo[a]pyrene and 1-nitropyrene. It was mutagenic to Salmonella (greater than 100 pg/plate) and exceptionally reactive to DNA when assessed by the 32P-postlabelling technique. 1-CMP was inactive in a mouse bone micronucleus assay when administered by gavage, probably due to hydrolysis, whose kinetics have been studied (t1/2 approximately 23 min at 37 degrees C). However, as expected, it was a potent skin toxin as determined by its activity as a mitogen to mouse skin and its contact allergenicity, as determined using the local lymph node proliferative assay. It is concluded that 1-CMP will probably be a potent human skin carcinogen and contact allergen.

Animals↗