Partial Purification and Properties of a Cysteine Protease from Citrus Red Mite Panonychus citri

Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion.

Panonychus citri induced allergy among Yuzu farm workers in Koheung area / 천식및알레르기

BACKGROUND: Citrus red mite (CRM; Panonychus citri), which damages the peels and leaves of Citrus, has been reported as an important occupational allergen in Citrus farm workers. Yuzu belongs to the Citrus genus and its peels are the favorite material for tea in Korea. AIMS: We evaluated the prevalence of the sensitization to CRM in Yuzu farm workers in Koheung area (Southern provinces of Korean peninsula) and analyzed the allergenicity of CRM and the cross-reactivity between CRM and Dermatophagoides pteronyssinus (DP) with the sera of the workers and urbanites. METHODS: One hundred and eleven Yuzu farm workers and 36 respiratory allergic urban patients were enrolled in this study. Skin prick test (SPT) to CRM and DP was performed. CRM specific IgE was detected by ELISA and immunoblotting method. Cross-reactivity was investigated through inhibition ELISA and inhibition immunoblotting. RESULTS: About 39% of the workers showed positive response to CRM in SPT. Prevalence of allergic disease was 66%. Symptoms were associated with their work in 53% of patients. CRM-specific IgE from workers was not inhibited by DP crude antigen but CRM-specific IgE from urban patients was inhibited by DP crude antigen by an average of 70%. With immuno- blotting, we could identify 14.5, 15, 17, 18, 21, 22, 32, 33, 49.5 kDa CRM allergens with the sera of the worker. CONCLUSIONS: These results suggest that CRM is one of the unique occupational allergens to the Yuzu farm workers. Cross-reactivity between CRM and DP was found in urban patients.