SUMMARYWe have previously identified the hevein preprotein as a common allergen for latex allergic healthcare workers. The B cell epitopes in the hevein protein that are recognized by IgE of latex-allergic individuals have not been identified. In this study, we examined the hevein preprotein using epitope mapping. Overlapping synthetic peptides of 10 amino acids (two aa overlap) were synthesized on a derivatized cellulose membrane using Fmoc chemistry. The peptide spots were probed with pooled sera from 10 latex-allergic patients, and the IgE-reactive peptides identified with anti-IgE MoAbs. We identified six B cell epitopes within the full length hevein preprotein which bound IgE from latexallergic patients. Two were located in the N-terminal 5-kD hevein domain and four were observed in the 14-kD C-domain. A broad epitope was located between the N-terminal amino acids 13-24. This epitope had nearly complete homology to wheat germ agglutinin (WGA). Immunological cross-reactivity to WGA was confirmed by Western blot analysis with purified WGA, and this reactivity could be inhibited by latex proteins or WGA. Of the five remaining epitopes, four had homologies to other proteins in the pathogenesis-related family of plant proteins (PR-4). The data demonstrate that hevein has multiple IgE epitopes. The significant homology of these epitopes to a broad family of plant defence proteins further explains the increased prevalence of food allergies in latex-allergic individuals.

SUMMARYWe previously identified a 46-kD protein allergen in latex as having amino acid sequence homology to the patatin gene family. The objective of this study was to characterize this protein by molecular techniques. RNA was isolated from the latex or leaf material from Hevea brasiliensis and from potato tubers. Specific polymerase chain reaction (PCR) primers were designed from the amino acid sequence and reverse transcriptase (RT)-PCR amplified a specific product from latex RNA that was subsequently cloned and sequenced. This product was 1493 bp in length with an 1167 bp open reading frame. The deduced amino acid sequence encodes for a 389 aa protein, pI 4·82 with 43% homology to tobacco patatin. Northern analysis of potato, Hevea leaf, and latex RNA demonstrated the message to be most abundant in latex, weakly present in Hevea leaf, but no hybridization occurred with potato RNA. Patatin has lipid acyl-transferase and PLA 2 -like activity, suggesting it plays a role as a defence-related protein.Other defence-related proteins in latex such as hevein, glucanase, and hevamine are also allergens. Increased production of defence-related proteins as a result of increased tapping of the rubber trees to meet the demand for latex may explain the increased allergenicity of latex.

Mycoplasmafermentans is one of several Mycoplasma species that have been reported to stimulate tumor necrosis factor (TNF) secretion from monocytes. This activity has been associated primarily with the mycoplasma membrane fraction. In this article, we have characterized a membrane protein that stimulates TNF and interleukin 1,B secretion. The TNF-releasing activity partitioned into the Triton X-114 detergent phase, suggesting that the molecule is hydrophobic. The secretion of TNF is elevated in the presence of serum, which suggests that a serum component may play a role in the interaction between this mycoplasma protein and monocytes. Treatment of monocytes with monoclonal anti-CD14 antibody had no efect on the levels of TNF-releasing activity. By using the monocyte Western blot (immunoblot) technique, we have determined the molecular mass of the active molecule to be 48 kDa. This molecule appears to be distinct from the recently described family of variable lipoproteins of M. fermentans. Mycoplasma particulate material treated with proteinase K lost all inducing activity, whereas lipoprotein lipase-treated samples retained some level of activity.

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Guayule (Parthenium argentatum) is under cultivation in the southwestern United States as an alternative source of natural rubber free from proteins that cause Type I latex allergies. However, since guayule lacks the protein‐polymer interactions present in Hevea latex, its physical and chemical properties may differ. The solvent‐soluble (Sol) and insoluble (Gel) fractions from guayule and Hevea natural rubbers were isolated through a solubilization/centrifugation deproteinization process. Protein could be reduced or removed by centrifugation, or concentrated in the gel fraction for both Hevea and guayule rubber. Separation of the sol fraction of Hevea rubber reduced the overall protein level, in some cases to below detection limits, without impacting rubber thermo‐oxidative stability. Notably, no detectable cross reactions took place between guayule protein antibodies and Hevea‐based materials, nor vice‐versa. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42051.