Biomedical subjects

Richard E Goodman

Publications and source records attributed to Richard E Goodman.

6 recordsLinked to original sources

PubMed2006

Detecting fish parvalbumin with commercial mouse monoclonal anti-frog parvalbumin IgG.

Parvalbumin is a calcium-binding muscle protein that is highly conserved across fish species and amphibians. It is the major cross-reactive allergen associated with both fish and frog allergy. We used two-dimensional electrophoretic and immunoblotting techniques to investigate the utility of a commercial monoclonal anti-frog parvalbumin IgG for detecting parvalbumin present in some commonly consumed fish species. The 2D electrophoresis and immunoblots revealed species-specific differences in proteins that appear to represent various numbers of isoforms of parvalbumin in carp (5), catfish (3), cod (1) and tilapia (2). No parvalbumin was detected in yellowfin tuna. Based on minor differences in relative intensities of protein staining and immunodetection, parvalbumin isoforms may have slight differences in the epitope region recognized by the anti-frog parvalbumin antibody. These results suggest that the frog anti-parvalbumin antibody can be used as a valuable tool to detect parvalbumins from the fish tested in this study, except yellowfin tuna.

Allergens↗

PubMed2006

Evaluation of IgE binding to proteins of hardy (Actinidia arguta), gold (Actinidia chinensis) and green (Actinidia deliciosa) kiwifruits and processed hardy kiwifruit concentrate, using sera of individuals with food allergies to green kiwifruit.

BACKGROUND: Allergy to green kiwifruit has become common since the fruit was introduced in North America and Europe 30 years ago. Gold kiwifruit, more recently introduced commercially, has been shown to bind IgE from some individuals allergic to green kiwifruit. Hardy kiwifruit is a third species that is now cultivated in North America with potential application as a fresh fruit and in processed foods. OBJECTIVE: To compare the IgE binding properties of proteins in hardy kiwifruit extract and processed hardy kiwifruit concentrate to each other and to extracts of green and gold kiwifruits to evaluate the potential for allergic cross-reactions. METHODS: Sera from kiwifruit-allergic subjects and individuals without allergies to kiwifruit were assayed for IgE binding to soluble proteins in green, gold and hardy kiwifruits and heat-processed concentrate from hardy kiwifruit using immunoblots and direct enzyme-linked immunosorbent assay (ELISA). RESULTS: Marked IgE binding to specific hardy kiwifruit proteins was identified. However, IgE binding to heat-processed hardy kiwifruit concentrate was remarkably lower than to the raw fruit extract. CONCLUSIONS: These results suggest that some kiwifruit-allergic individuals may suffer allergic cross-reactions if they consume raw hardy kiwifruit. However, heat processing of the hardy kiwifruit alters allergenic protein structure, dramatically reducing in vitro IgE binding. Processing likely reduces the risk of eliciting an allergic response in those with allergies to raw kiwifruit.

Actinidia↗

PubMed2006

Practical and predictive bioinformatics methods for the identification of potentially cross-reactive protein matches.

A bioinformatics comparison of proteins introduced into food crops through genetic engineering provides a mechanism to identify those proteins that may present an increased risk of allergic reactions for individuals with existing allergies. The goal is to identify proteins that are known to be allergens or are so similar to an allergen that they may induce allergic cross-reactions. Three comparative approaches have traditionally been used, or considered for safety evaluations. One identifies any short (6-8) amino acid segment of the protein that exactly matches a known allergen sequence. The second is an overall primary sequence comparison using Basic Local Alignment Search Tool (BLAST) or FASTA to find matches of greater than 35% identity over 80 amino acids. The third is based on 3-D prediction programs to identify 3-D similarities that might predict potential cross-reactivity. The utility of each of these approaches was debated in the bioinformatics workshop. The consensus agreement from the expert workshop participants was that the short-segment match (e. g., 6-8 amino acids) provides an unacceptably high rate of false positive matches and an uncertain rate of true positive matches, and was not particularly useful for an allergenicity evaluation performed in the context of comprehensive safety evaluation. There was no consensus regarding the most appropriate bioinformatics method, an acceptable scoring criteria for triggering closer examination subsequent to a positive match, or an acceptable scoring mechanism for ranking the utility of the various 3-D approaches that were discussed during the workshop. However, the general consensus was that the most practical approach at this time is to evaluate primary sequence identities to known allergens using either FASTA or BLAST. While there was good agreement that identities of greater than 35% over 80 or more amino acids (recommended by Codex in 2003) is quite conservative, the conclusion was that additional data or studies would be needed to justify changing this criterion as there is some evidence that some individuals sensitized to proteins in evolutionarily conserved protein families may experience cross-reactions to proteins sharing approximately 40% identity.

Algorithms↗

PubMed2005

Assessing genetically modified crops to minimize the risk of increased food allergy: a review.

The first genetically modified (GM) crops approved for food use (tomato and soybean) were evaluated for safety by the United States Food and Drug Administration prior to commercial production. Among other factors, those products and all additional GM crops that have been grown commercially have been evaluated for potential increases in allergenic properties using methods that are consistent with the current understanding of food allergens and knowledge regarding the prediction of allergenic activity. Although there have been refinements, the key aspects of the evaluation have not changed. The allergenic properties of the gene donor and the host (recipient) organisms are considered in determining the appropriate testing strategy. The amino acid sequence of the encoded protein is compared to all known allergens to determine whether the protein is a known allergen or is sufficiently similar to any known allergen to indicate an increased probability of allergic cross-reactivity. Stability of the protein in the presence of acid with the stomach protease pepsin is tested as a risk factor for food allergenicity. In vitro or in vivo human IgE binding are tested when appropriate, if the gene donor is an allergen or the sequence of the protein is similar to an allergen. Serum donors and skin test subjects are selected based on their proven allergic responses to the gene donor or to material containing the allergen that was matched in sequence. While some scientists and regulators have suggested using animal models, performing broadly targeted serum IgE testing or extensive pre- or post-market clinical tests, current evidence does not support these tests as being predictive or practical. Based on the evidence to date, the current assessment process has worked well to prevent the unintended introduction of allergens in commercial GM crops.

Animals↗

PubMed2002

Bioinformatic methods for allergenicity assessment using a comprehensive allergen database.

BACKGROUND: A principal aim of the safety assessment of genetically modified crops is to prevent the introduction of known or clinically cross-reactive allergens. Current bioinformatic tools and a database of allergens and gliadins were tested for the ability to identify potential allergens by analyzing 6 Bacillus thuringiensis insecticidal proteins, 3 common non-allergenic food proteins and 50 randomly selected corn (Zea mays) proteins. METHODS: Protein sequences were compared to allergens using the FASTA algorithm and by searching for matches of 6, 7 or 8 contiguous identical amino acids. RESULTS: No significant sequence similarities or matches of 8 contiguous amino acids were found with the B. thuringiensis or food proteins. Surprisingly, 41 of 50 corn proteins matched at least one allergen with 6 contiguous identical amino acids. Only 7 of 50 corn proteins matched an allergen with 8 contiguous identical amino acids. When assessed for overall structural similarity to allergens, these 7 plus 2 additional corn proteins shared >or=35% identity in an overlap of >or=80 amino acids, but only 6 of the 7 were similar across the length of the protein, or shared >50% identity to an allergen. CONCLUSIONS: An evaluation of a protein by the FASTA algorithm is the most predictive of a clinically relevant cross-reactive allergen. An additional search for matches of 8 amino acids may provide an added margin of safety when assessing the potential allergenicity of a protein, but a search with a 6-amino-acid window produces many random, irrelevant matches.

Algorithms↗

PubMedDate not supplied

Assessing the allergenicity of proteins introduced into genetically modified crops using specific human IgE assays.

Global commercial production of genetically modified (GM) crops has grown to over 67 million hectares annually, primarily of herbicide-tolerant and insect protection crop varieties. GM crops are produced by the insertion of specific genes that either encode a protein, or a regulatory RNA sequence. A comprehensive safety evaluation is conducted for each new commercial GM crop, including an assessment of the potential allergenicity of any newly introduced protein. If the gene was derived from an allergenic organism, or the protein sequence is highly similar to a known allergen, immunoassays, e.g., Western blot assays and enzyme-linked immunosorbent assay tests, are performed to identify protein-specific IgE binding by sera of individuals allergic to the gene source, or the source of the sequence-matched allergen. Although such assays are commonly used to identify previously unknown allergens, criteria have not been established to demonstrate that a protein is unlikely to cause allergic reactions. This review discusses factors that affect the predictive value of these tests, including clinical selection criteria for serum donors, selection of blocking reagents to reduce nonspecific antibody binding, inhibition assays to verify specificity of binding, and scientifically justified limits of detection (sensitivity) in the absence of information regarding biological thresholds.

Allergens↗