To study the asthmatogenic effect of certain airborne elements of the home environment, we studied a group of guinea pigs exposed to aerosolized cockroach allergen (CRa) and side-stream cigarette (S-SC) smoke. Four groups of guinea pigs were exposed to aerosols, either saline or CRa, for 4 weeks, after a sham or S-SC smoke pretreatment. Anaphylactic antibodies were measured by passive cutaneous anaphylaxis (PCA) assay and by skin test. Animals were challenged with aerosol CRa on day 35, and lung function and leukotrienes (LTB₄ and LTC₄/D₄) were measured. Skin tests were positive on days 21 and 29. The antibodies were heat-stable, IgG1a-like antibodies (PCA titers 1:2–18). The CRa challenge caused an immediate reduction in both the maximal expiratory flow rate at 50% of the lung capacity and respiratory compliance. The decreased lung function continued for up to 6 h (p < 0.0001). LTB₄ and LTC₄/D₄ were elevated (p < 0.0001) in the sensitized animals at the corresponding times of reduced lung function. S-SC smoke did not affect the CRa sensitization; instead, a protective effect on the CRa-induced bronchospasms was noted. Thus, the study indicates that a simple airborne CRa exposure without an adjuvant sensitizes guinea pigs, and that the animals respond to antigen challenge with CRa-specific airway obstructions.

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Of the various arthropods, humans have the greatest contact with mites and cockroaches, and as a result, allergies to these two groups have been the most frequently reported. Changes in lifestyle and living environment have encouraged the growth of arthropods other than mites and cockroaches, and consequently, human exposure to antigens derived from the new arthropods has increased. Although systematic approaches to and immunobiochemical studies of these arthropods are relatively sparse compared with those of mites and cockroaches, recent reports have shown that many species of household arthropods can elicit IgE-mediated reactions via inhalation, biting, or stinging. In this chapter, we review the other arthropods that can induce allergic reaction to human beings. Where the information exists, the frequency of sensitivity and clinical manifestation, and the characterization of the allergens are also reviewed. Virtually all species of arthropods may be sources of allergens that can sensitize and induce IgE-mediated allergic reactions in humans.

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