Denise M. Sailstad

THE MOUSE IgE TEST: INTERLABORATORY EVALUATION AND COMPARISON OF BALB/c AND C57BL/6 STRAIN MICE

The mouse IgE test is a novel method for the prospective identification of chemicals that have the potential to cause allergic sensitization of the respiratory tract. Activity is measured as a function of increases in the concentration of total serum IgE induced by topical exposure of mice to chemicals; those chemicals that elicit a substantial elevation in IgE are classified as respiratory allergens. The present investigations were designed to evaluate further the utility of the mouse IgE test. For this purpose theassay was conducted in each of fiveindependent laboratories using trimellitic anhydride (TMA), a known cause of respiratory sensitization and occupational asthma, and 2,4-dinitrochlorobenzene (DNCB), a potent contact allergen that is considered not to cause sensitization of the respiratory tract. For these investigations BALB/c mice were used, which are currently the strain of choice for the mouse IgE test. In four of five laboratories, exposure of mice to TMA caused a statistically significant...

Dietary vitamin A enhances sensitivity of the local lymph node assay

Murine assays such as the mouse ear swelling test (MEST) and the local lymph node assay (LLNA) are popular alternatives to guinea pig models for the identification of contact sensitizers, yet there has been concern over the effectiveness of these assays to detect weak and moderate sensitizers. Much work has been done to improve the sensitivity of the MEST, including the addition of a vitamin A acetate (VAA) enriched diet, which increases its sensitivity. Vitamin A acetate has been reported to increase the numbers of Langerhans cells (antigen presenting cells) in the skin, which could in turn enhance the cellular immune response. Because the LLNA relies on tritiated-thymidine incorporation by proliferating T cells during the induction phase, we have studied the potential of the VAA diet to enhance sensitivity of the LLNA. Results indicate that the VAA enriched diet significantly increased the LLNA sensitivity to formalin, eugenol, glutaraldehyde, trimellitic anhydride, and an azo dye at concentrations where no proliferation was observed in mice maintained on the standard diet. Maintenance on a VAA diet for 3 weeks prior to initiating the sensitization procedure was optimal. Thus, incorporation of a VAA diet improves the sensitivity of the LLNA as a quick, objective, and relatively inexpensive screen for detecting moderate and weak contact sensitizers.

Evaluation of Several Variations of the Mouse Ear Swelling Test (MEST) for Detection of Weak and Moderate Contact Sensitizers

The ability of a chemical to cause contact sensitization has traditionally been evaluated in animal models typically using the guinea pig. However, these methods are expensive and require subjective analysis of erythema, which makes evaluation of dyes difficult. The mouse ear swelling test (MEST) is a more quantitative and less costly method, but it has not always been reliable for the detection of moderate and weak sensitizers. To identify a MEST that can reliably detect weak sensitizers, several published MEST procedures were examined using the strong sensitizer 2,4-dinitrofluorobenzene (DNFB) and three weaker sensitizers, glutaraldehyde, formalin, and an azo dye (Solvent Red 1 [SR1]). Almost all variations of the MEST procedures detected the strong sensitizer (DNFB) after optimizing the chemical concentration and sensitizing procedure; however, only one protocol detected the weaker sensitizers, glutaraldehyde, formalin, and SR1. This sensitive MEST protocol required test animals to be fed a vitamin A-s...

Ultraviolet Radiation Downregulates Allergy in Balb/c Mice

The immunosuppressive effects of exposure to ultraviolet radiation (UVR) are well known and the underlying mechanisms extensively studied. The suppression of Th1 appears to account for UVR suppression of contact hypersensitivity and delayed-type hypersensitivity responses and increased susceptibility to certain infections and tumor development. The underlying mechanisms suggest Th2-mediated responses associated with immediate-type hypersensitivity and allergic lung disease should be unchanged or possibly enhanced by UVR. The hypothesis that UVR exposure enhances allergic lung disease in BALB/ c mice was tested. Effects of UVR on sensitization and elicitation of respiratory hypersensitivity were assessed using a fungal extract Metarhizium anisopliae (MACA), as the allergen. BALB/ c mice were sham or UVR (8 KJ/m2) exposed 3d before involuntary aspiration (IA) of MACA or vehicle. The mice received UVR exposures before the first and second of three IAs in the sensitization protocol and 3 d before the fourth IA in the elicitation protocol. Serum and bronchoalveolar lavage fluid (BALF) were harvested before (d 21, sensitization/d 24, elicitation) and at 1 (d 22/d 28), 3 (d 24/d 29), and 7 (d 28/d 35) d following the last IA. UVR exposure prior to sensitization suppressed two hallmarks of allergic disease, immune-mediated inflammation (eosinophil influx) and total immunoglobulin (Ig)E compared to the sham-UVR controls. There were no differences attributable to UVR exposure in previously sensitized mice. These data suggest that UVR exposure prior to sensitization suppresses allergic responses but has no effect on the elicitation of allergic responses in previously sensitized individuals. Consequently, there is no evidence that exposure to UVR enhances the induction or expression of allergic lung disease.

Evaluation of an Azo and Two Anthraquinone Dyes for Allergic Potential

Two dye mixtures and the individual component dyes were evaluated for the potential to induce contact or pulmonary hypersensitivity. These dye mixtures were suspect because of anecdotal reports of both pulmonary and contact hypersensitivity in assembly workers, and because the component dyes were structurally related to dyes known to be contact sensitizers. One mixture consisted of disperse blue 3 (DB3) and disperse red 11 (DR11), which are anthraquinones, and the other mixture contained DR11 and solvent red 1 (SR1), an azo dye. Contact hypersensitivity was examined using the local lymph node assay (LLNA) and a modified mouse ear swelling test (MEST). Both the MEST and the LLNA indicated that SR1 has weak contact-sensitizing potential. None of the other individual dye compounds or the two mixtures were identified as contact sensitizers by either method. To evaluate the mixtures as potential pulmonary allergens, guinea pigs were repeatedly exposed by inhalation (300 mg/m3, 6 hr/day) 5 days/week, for 1 week. Weekly exposures were repeated three times with 2 weeks of nonexposure time in between. Guinea pigs were then challenged through the jugular vein using a dye-dimethylsulfoxide mixture. During the challenge, breathing mechanics (dynamic compliance and resistance) were measured in mechanically ventilated animals. Changes in these measurements, indicative of bronchoconstriction, were not observed in animals exposed to either dye mixture, nor were antibodies detected in the sera of exposed animals using individual dye-specific enzyme-linked immunosorbent assays. In conclusion, two methods indicate that SR1 may have contact-sensitizing potential.(ABSTRACT TRUNCATED AT 250 WORDS)