Background: Proteins of natural rubber latex cause IgE-mediated sensitization in 3% to 18% of health care workers and in up to 50% of patients with spina bifida. Objective: This study was aimed at the generation of a comprehensive latex protein database by two-dimensional electrophoresis (2-DE). Methods: Proteins extracted from fresh Hevea brasiliensis latex were separated by 2-DE. IgE-reactive proteins were analyzed by immunoblotting with sera of health care workers with latex allergy. Protein microsequencing and monoclonal antibodies were used to identify the latex allergens. Results: The latex C-serum 2-DE map was very complex and exhibited about 200 distinct polypeptides. The proteins eluted from the latex particles consisted primarily of two groups of acidic proteins located in the 8 to 14 kd and 22 to 24 kd areas of the 2-DE map. Major IgE-reactivity was detected with C-serum proteins in the 56, 45, 30, 20, 14, and <6.5 kd areas of the immunoblots. The 8 to 14 kd particle proteins exhibited distinct IgE reactivity, whereas the 22 to 24 kd proteins were not stained. Seven of the soluble IgE-reactive protein spots showed high homology with enolase, superoxide dismutase, triosephosphate isomerase, proteasome subunit, and chitinase and represent previously undescribed latex allergens; whereas nine protein spots corresponded to known latex allergens, namely prohevein, hevein, prohevein C-domain, and hevamine. As identified by monoclonal antibodies, the IgE-reactive latex particle proteins mainly represent the allergenic rubber elongation factor. Conclusions: Two-dimensional electrophoresis, followed by immunoblotting and protein microsequencing, can rapidly identify a large number of IgE-binding latex proteins. The 2-DE latex maps generated will provide valuable information for the development of strategies to isolate the relevant latex allergens. Because the novel latex allergens are common plant enzymes, they may also act as cross-reacting proteins in various foods. (J Allergy Clin Immunol 1997;99:385-95.)
