PURPOSE: Cockroaches are the second leading allergen in Taiwan. Sensitization to Per a 2, the major American cockroach allergen, correlates with clinical severity among patients with airway allergy, but there is limited information on IgE epitopes and tissue localization of Per a 2. This study aimed to identify Per a 2 linear IgE-binding epitopes and its distribution in the body of a cockroach. METHODS: The cDNA of Per a 2 was used as a template and combined with oligonucleotide primers specific to the target areas with appropriate restriction enzyme sites. Eleven overlapping fragments of Per a 2 covering the whole allergen molecule, except 20 residues of signal peptide, were generated by PCR. Mature Per a 2 and overlapping deletion mutants were affinity-purified and assayed for IgE reactivity by immunoblotting. Three synthetic peptides comprising the B cell epitopes were evaluated by direct binding ELISA. Rabbit anti-Per a 2 antibody was used for immunohistochemistry. RESULTS: Human linear IgE-binding epitopes of Per a 2 were located at the amino acid sequences 57-86, 200-211, and 299-309. There was positive IgE binding to 10 tested Per a 2-allergic sera in 3 synthetic peptides, but none in the controls. Immunostaining revealed that Per a 2 was localized partly in the mouth and midgut of the cockroach, with the most intense staining observed in the hindgut, suggesting that the Per a 2 allergen might be excreted through the feces. CONCLUSIONS: Information on the IgE-binding epitope of Per a 2 may be used for designing more specific diagnostic and therapeutic approaches to cockroach allergy.
Amino Acid Sequence ; Cockroaches ; DNA Primers ; DNA, Complementary ; Enzyme-Linked Immunosorbent Assay ; Epitope Mapping* ; Epitopes ; Epitopes, B-Lymphocyte ; Feces ; Humans ; Hypersensitivity ; Immunoblotting ; Immunoglobulin E ; Immunohistochemistry ; Mouth ; Peptides ; Periplaneta* ; Polymerase Chain Reaction ; Protein Sorting Signals ; Taiwan

PURPOSE: Fungi have been known to be important aeroallergens for hundreds of years. Most studies have focused on total fungal concentration; however, the concentration of specific allergenic fungi may be more important on an individual basis. METHODS: Ten fungal allergic patients and 2 non-fungal allergic patients were enrolled. The patients with a decrease in physician or patient global assessment by more than 50% of their personal best were considered to have an exacerbation of allergic symptoms and to be in the active stage. Those who maintained their physician and patient global assessment scores at their personal best for more than 3 months were considered to be in the inactive stage. The concentrations of dominant fungi in the patients' houses and outdoors were measured by direct and viable counts at active and inactive stages. RESULTS: The exacerbation of allergic symptoms was not correlated with total fungal spore concentration or the indoor/outdoor ratio (I/O). Specific fungi, such as Cladosporium oxysporum (C. oxyspurum), C. cladosporioides, and Aspergillus niger (A. niger), were found to be significantly higher concentrations in the active stage than in the inactive stage. Presumed allergenic spore concentration threshold levels were 100 CFU/m3 for C. oxysporum, and 10 CFU/m3 for A. niger, Penicillium brevicompactum and Penicillium oxalicum. CONCLUSIONS: The major factor causing exacerbation of allergic symptoms in established fungal allergic patients may be the spore concentration of specific allergenic fungi rather than the total fungal concentration. These results may be useful in making recommendations as regards environmental control for fungal allergic patients.
Aspergillus niger ; Cladosporium ; Colony Count, Microbial* ; Family Characteristics ; Fungi ; Humans ; Hypersensitivity* ; Niger ; Penicillium ; Spores* ; Spores, Fungal