CHARACTERIZATION AND IDENTIFICATION OF LATEX ALLERGENS BY 2-DIMENSIONAL ELECTROPHORESIS AND PROTEIN MICROSEQUENCING

Background: Proteins of natural rubber latex cause IgE-mediated sensit ization in 3% to 18% df health care workers and in up to 50% of patien ts with spina bifida. Objective: This study was aimed at the generatio n of a comprehensive latex protein database by two-dimensional electro phoresis (2-DE). Methods: Proteins extracted from fresh Hevea brasilie nsis 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 ident ify the latex allergens. Results: The latex C-serum 2-DE map was very complex and exhibited about 200 distinct polypeptides. The proteins el uted from the latex particles consisted primarily of two groups of aci dic 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 2 2 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 rep resent previously undescribed latex allergens; whereas nine protein sp ots corresponded to known latex allergens, namely prohevein, hevein, p rohevein C-domain, and hevamine. As identified by monoclonal antibodie s, the IgE-reactive latex particle proteins mainly represent the aller genic rubber elongation factor. Conclusions: Two-dimensional electroph oresis, followed by immunoblotting and protein microsequencing, can ra pidly identify a large number of IgE-binding latex proteins. The 2-DE latex maps generated will provide valuable information for the develop ment of strategies to isolate the relevant latex allergens. Because th e novel latex allergens are common plant enzymes, they may also act as cross-reacting proteins in various foods.