PLANT DEFENSE-RELATED ENZYMES AS LATEX ANTIGENS

Background: Latex allergy is an increasing hazard to people who freque ntly come into contact with latex products. Of interest concerning thi s immediate-type allergy is the crossreactivity to various vegetable f oods and pollen. Despite its high prevalence, no adequate explanation has been provided for the cross-reactive antigens. Objective: We have hypothesized that a series of plant defense-related proteins act as la tex allergens, as well as vegetable food allergens. To evaluate this h ypothesis, hydrolytic enzymes that are very likely to take on defensiv e roles in rubber trees were examined for their antigenicity. Methods: By applying chromatographic procedures, defense-related enzymes were separated from nonammoniated latex (NAL). Their antigenicity was exami ned by immunoblotting and ELISA with sera containing IgE antibodies to crude latex proteins. Results: Three kinds of hydrolytic enzymes (bas ic beta-1,3-glucanases [35, 36.5, and 38 kd], a basic chitinase/lysozy me [29.5 kd], and an acidic esterase [44 kd]) were separated from NAL. They were recognized by IgE antibodies from a significant number of p atients allergic to latex. The basic beta-1,3-glucanases and the acidi c esterase were also strongly recognized by IgE antibodies from severa l atopic subjects who were allergic to various vegetable foods rather than latex products. Conclusion: It was ascertained that the three def ense-related enzymes separated from NAL constituted part of the latex antigens. Taking together the well-known serologic or immunologic rela tionships and amino acid sequence similarities of defense-related prot eins coming from phylogenetically distant plant species, we can suspec t their universal antigenicity and cross-reactivity.