Hev b 11, a class I chitinase, is another allergen from Hevea latex with a chitin binding domain and displays a different IgE binding capacity compared with hevein.

Allergies to certain fruits such as banana, avocado, chestnut and kiwi are described in 30–70% of latex-allergic patients. This association is attributed to the cross-reactivity between the major latex allergen hevein and hevein-like domains (HLDs) from fruit class I chitinases. We aimed to assess the extent of cross-reactivity between hevein and HLDs using sera from latex-allergic patients with and without plant food allergy. Hevein and HLDs of latex, banana, and avocado chitinases were expressed in Escherichia coli as fusion proteins with the maltose-binding protein and purified by affinity chromatography. IgE binding to these proteins was studied in sera from 59 latex-allergic patients and 20 banana-allergic patients without latex allergy by ELISA and ELISA inhibition. Additionally, 16,408 allergic patients’ sera were tested for IgE binding to hevein, latex chitinase, and wheat germ agglutinin using an allergen microarray. Hevein-specific IgE was detected in 34/59 (58%) latex-allergic patients’ sera. HLDs of latex, banana, and avocado chitinases were recognized by 21 (36%), 20 (34%), and 9 (15%) sera, respectively. In contrast, only one of 20 banana-allergic patients without latex allergy was sensitized to chitinase HLDs. In most tested latex-allergic patients’ sera, IgE binding to hevein was only partially reduced by preincubation with HLDs. Among hevein-sensitized, latex-allergic patients, the percentage of plant food allergy (15/34 = 44%) was equal to latex-allergic patients without hevein sensitization (11/25 = 44%). In the general allergic population, 230 of 16,408 sera (1.4%) reacted to hevein and/or a hevein-like allergen. Of these, 128 sera showed an isolated sensitization to hevein, whereas only 17 bound to latex chitinase or wheat germ agglutinin without hevein sensitization. In conclusion, the IgE response to HLDs is elicited by hevein as sensitizing allergen in most cases. Despite considerable cross-reactivity between these allergens, no correlation between latex-associated plant food allergy and sensitization to hevein or HLDs was found.

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SummaryRapid and efficient procedures for the detection of sequence polymorphisms are essential for chromosomal walking and mutation detection analyses. While DNA chip technology and denaturing high-performance liquid chromatography (DHPLC) are the methods of choice for large scale facilities, small laboratories are dependent on simple ready-to-use techniques. We show that heteroduplex analysis on high resolution gel matrices efficiently detects sequence polymorphism differing as little as a single base pair (e.g. single-nucleotide polymorphism, SNP) with standard laboratory equipment. Furthermore, the matrices also discerned differences between homoduplexes, a prerequisite for co-dominant markers. The markers thus generated are referred to as duplex analysis markers. We designed PCR primers for 36 Arabidopsis thaliana loci ranging in length from 230 bp to 1000 bp. Among three ecotypes, more than half (n⍧ 19) of the loci examined were polymorphic; five of which contained three different alleles. This simple, high resolution technique can be used to rapidly convert sequence tagged sites into co-dominant PCR-based molecular markers for fine-scale mapping studies and chromosomal walking strategies as well as for the detection of mutations in particular genes.