Monoclonal antibody specific to a major fish allergen: parvalbumin

Microfluidic Chip Coupled with MALDI-TOF MS for Multitarget Detection of Allergens in Crucian Carp (Carassius auratus)

The goal of the present study was to establish a rapid, simple method for simultaneous allergy testing of sera from multiple fish-allergic patients. Sera from fish-allergic patients were pooled and used for capturing allergens in fish muscle of crucian carp (Carassius auratus), which was studied as a fish model. Sarcoplasmic proteins of crucian carp (Carassius auratus) were extracted for the analysis of allergens. Anti-human IgE antibody-functionalized magnetic beads were utilized to collect IgE antibodies from human pooled sera. The isolation of allergenic proteins was immunomagnetically performed in microfluidic channels, and the elution of the captured allergenic proteins was done with 5% (v/v) acetic acid aqueous solution. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and peptide mass fingerprinting were used for the analysis of tryptic digests of eluted proteins. Ten potential allergenic proteins were identified from crucian carp (Carassius auratus). The present protocol provides a rapid, efficient, and simple method for simultaneous detection of multiple allergens, based on multitargeted antibodies from pooled sera of allergic patients. The constructed multiple antibody-modified MBs can be applied for the deallergenicity of food matrices. The efficiency of allergen detection can be greatly improved, with promising application in allergen discovery and filtration for other muscle-based foods.

Thermostable allergens in canned fish: Evaluating risks for fish allergy

BACKGROUND

Major fish allergens, including parvalbumin (PV), are heat stable and can withstand extensive cooking processes. Thus, the management of fish allergy generally relies on complete avoidance. Fish-allergic patients may be advised to consume canned fish, as some fish-allergic individuals have reported tolerance to canned fish. However, the safety of consuming canned fish has not been evaluated with comprehensive immunological and molecular analysis of canned fish products.

METHODS

We characterized the in vitro immunoreactivity of serum obtained from fish-allergic subjects to canned fish. Seventeen canned fish products (salmon n = 8; tuna n = 7; sardine n = 2) were assessed for the content and integrity of PV using allergen-specific antibodies. Subsequently, the sIgE binding of five selected products was evaluated for individual fish-allergic patients (n = 53). Finally, sIgE-binding proteins were identified by mass spectrometry.

RESULTS

The canned fish showed a markedly reduced PV content and binding to PV-specific antibodies compared with conventionally cooked fish. However, PV and other heat-stable fish allergens, including tropomyosin and collagen, still maintained their sIgE-binding capacity. Of 53 patients, 66% showed sIgE binding to canned fish proteins. The canned sardine contained proteins bound to sIgE from 51% of patients, followed by canned salmon (43%-45%) and tuna (8%-17%). PV was the major allergen in canned salmon and sardine. Tropomyosin and/or collagen also showed sIgE binding.

CONCLUSION

We showed that canned fish products may not be safe for all fish-allergic patients. Canned fish products should only be considered into the diet of individuals with fish allergy, after detailed evaluation which may include in vitro diagnostics to various heat-stable fish allergens and food challenge conducted in suitable environments.

Seafood allergy: Allergen, epitope mapping and immunotherapy strategy

Seafoods are fashionable delicacies with high nutritional values and culinary properties, while seafood belongs to worldwide common food allergens. In recent years, many seafood allergens have been identified, while the diversity of various seafood species give a great challenge in identifying and characterizing seafood allergens, mapping IgE-binding epitopes and allergen immunotherapy development, which are critical for allergy diagnostics and immunotherapy treatments. This paper reviewed the recent progress on seafood (fish, crustacean, and mollusk) allergens, IgE-binding epitopes and allergen immunotherapy for seafood allergy. In recent years, many newly identified seafood allergens were reported, this work concluded the current situation of seafood allergen identification and designation by the World Health Organization (WHO)/International Union of Immunological Societies (IUIS) Allergen Nomenclature Sub-Committee. Moreover, this review represented the recent advances in identifying the IgE-binding epitopes of seafood allergens, which were helpful to the diagnosis, prevention and treatment for seafood allergy. Furthermore, the allergen immunotherapy could alleviate seafood allergy and provide promising approaches for seafood allergy treatment. This review represents the recent advances and future outlook on seafood allergen identification, IgE-binding epitope mapping and allergen immunotherapy strategies for seafood allergy prevention and treatment.

Cross-reactive monoclonal antibodies against fish parvalbumins as a tool for studying antigenic similarity of different parvalbumins and analysis of fish extracts

Fish parvalbumins are heat-stable calcium-binding proteins that are highly cross-reactive in causing allergy symptoms in fish-sensitized patients. The reactivities of parvalbumin-specific monoclonal or polyclonal antibodies with parvalbumins of different fish species allowed their application for development of various immunoassays for allergen identification in fish samples. In this study, monoclonal antibodies (MAbs) were generated against two parvalbumins - natural Atlantic cod parvalbumin and recombinant common carp β-parvalbumin expressed in E. coli. Large collections of recombinant parvalbumins and natural allergen extracts of different fish species and other animals were used to identify the specificities of these MAbs using ELISA, Western blot, and dot blot. MAbs demonstrated different patterns of cross-reactivities with recombinant parvalbumins. Their binding affinities were affected by the addition and removal of Ca²⁺ ions. Moreover, all MAbs showed a broad reactivity with the target antigens in natural fish, chicken, and pork extracts. The ability of two MAbs (clones 7B2 and 3F6) to identify and isolate native parvalbumins from allergen extracts was confirmed by Western blot. Epitope mapping using recombinant fragments of Atlantic cod parvalbumin (Gad m 1) and common carp parvalbumin (Cyp c 1) revealed that 4 out of 5 MAbs recognize parvalbumin regions that contain calcium binding sites. In conclusion, the generated broadly reactive well-characterized MAbs against fish β-parvalbumins could be applied for investigation of parvalbumins of fish and other animals and their detection in allergen extracts.

Parvalbumin: A Major Fish Allergen and a Forensically Relevant Marker

Parvalbumins (PVALBs) are low molecular weight calcium-binding proteins. In addition to their role in many biological processes, PVALBs play an important role in regulating Ca2+ switching in muscles with fast-twitch fibres in addition to their role in many biological processes. The PVALB gene family is divided into two gene types, alpha (α) and beta (β), with the β gene further divided into two gene types, beta1 (β1) and beta2 (β2), carrying traces of whole genome duplication. A large variety of commonly consumed fish species contain PVALB proteins which are known to cause fish allergies. More than 95% of all fish-induced food allergies are caused by PVALB proteins. The authentication of fish species has become increasingly important as the seafood industry continues to grow and the growth brings with it many cases of food fraud. Since the PVALB gene plays an important role in the initiation of allergic reactions, it has been used for decades to develop alternate assays for fish identification. A brief review of the significance of the fish PVALB genes is presented in this article, which covers evolutionary diversity, allergic properties, and potential use as a forensic marker.

Development of a sensitive sandwich ELISA with broad species specificity for improved fish allergen detection

A sensitive Enzyme-linked Immunosorbent Assay (ELISA) with improved broad species specificity was developed for the detection of southern hemisphere fish residues in processed foods. The polyclonal antibodies were raised against parvalbumins from 13 fish species representing 7 fish orders selected for their molecular diversity and immunoreactivity profile. The optimized ELISA-2 (based on the rabbit capture antibody (RB#4) - sheep detection antibody (S2#4) pair) displayed an improved detection limit of 0.6 μg/L (3.7 μg of /kg). Our immunoreactivity-directed species selection approach in the strategized antibody production significantly improved the detection of no or weakly immunoreactive fish species previously not detected immunochemically. Of 37 commercially important fish species tested, the ELISA-2 could detect 28 fish species (76%). The optimized sample extraction with a buffer additive achieved good protein recoveries of 87.2 - 117.3% (within the AOAC recommended range). The ELISA-2 was able to detect fish residues in five highly processed food products.

Development and Characterization of Monoclonal Antibodies for the Detection of Fish Protein

This study developed and characterized anti-fish monoclonal antibodies (mAbs) capable of detecting fish, a major allergenic food, in processed food products to protect fish sensitized individuals. Of the three mAbs raised against crude protein extract of cooked fish muscle, mAb 8F5 exhibited a positive reaction to all 50 common food fish species tested with no cross-reactions to shellfish, land animals, or food additives. Although the ELISA results were negative against swordfish and yellowfin tuna, western blot clearly detected both after cooking. The ~36 kDa antigenic protein of mAb 8F5, which was found in all fish species, was detectable by mAb 8F5 in all of the fish samples even after prolonged heat treatment (100 °C, up to 60 min). These findings suggest that mAb 8F5 has great potential utility as a probe for the immunochemical detection of fish tissue in cooked food.

Effect of Processing on Fish Protein Antigenicity and Allergenicity

Fish allergy is a life-long food allergy whose prevalence is affected by many demographic factors. Currently, there is no cure for fish allergy, which can only be managed by strict avoidance of fish in the diet. According to the WHO/IUIS Allergen Nomenclature Sub-Committee, 12 fish proteins are recognized as allergens. Different processing (thermal and non-thermal) techniques are applied to fish and fishery products to reduce microorganisms, extend shelf life, and alter organoleptic/nutritional properties. In this concise review, the development of a consistent terminology for studying food protein immunogenicity, antigenicity, and allergenicity is proposed. It also summarizes that food processing may lead to a decrease, no change, or even increase in fish antigenicity and allergenicity due to the change of protein solubility, protein denaturation, and the modification of linear or conformational epitopes. Recent studies investigated the effect of processing on fish antigenicity/allergenicity and were mainly conducted on commonly consumed fish species and major fish allergens using in vitro methods. Future research areas such as novel fish species/allergens and ex vivo/in vivo evaluation methods would convey a comprehensive view of the relationship between processing and fish allergy.

IgE-Mediated Fish Allergy in Children

Fish allergy constitutes a severe problem worldwide. Its prevalence has been calculated as high as 7% in paediatric populations, and in many cases, it persists into adulthood with life-threatening signs and symptoms. The following review focuses on the epidemiology of Immunoglobulin E (IgE)-mediated fish allergy, its pathogenesis, clinical manifestations, and a thorough approach to diagnosis and management in the paediatric population. The traditional approach for managing fish allergy is avoidance and rescue medication for accidental exposures. Food avoidance poses many obstacles and is not easily maintained. In the specific case of fish, food is also not the only source of allergens; aerosolisation of fish proteins when cooking is a common source of highly allergenic parvalbumin, and elimination diets cannot prevent these contacts. Novel management approaches based on immunomodulation are a promising strategy for the future of these patients.

A review on food processing and preparation methods for altering fish allergenicity

People eat many varieties of food to satiate their hunger. Among them, a few numbers of food cause overreaction of the body's immune system, and fish holds a permanent position on that list. Processing methods, including one treatment or a combination, can have different effects on the allergenic potential of food proteins. An important point to note, however, is that not all of these methods can eliminate the potential for protein allergy. Thus, it is essential to understand the risk involved with the consumption of processed fish and its derivatives. Fish could be prepared in various ways before come to the dining plate. It has shown some of these methods can effectively manipulate the allergenicity owing to the alterations occurred in the protein conformation. This article provides an overview of the impact of fish processing methods (thermal and non-thermal) on the allergenic potential of fish along with possible causative structural modification provokes allergen stability. The article begins with current trends related to fish consumption, proceeds with the prevalence and underlying mechanism of fish allergy. Properties of clinically relevant fish proteins, projected IgE epitopes of PV, cross-reactivity of fish allergens are also addressed in this context to understand and compare the behavioral patterns of PV profiles of different species on processing methods.

Prolonged fasting followed by refeeding modifies proteome profile and parvalbumin expression in the fast-twitch muscle of pacu (Piaractus mesopotamicus)

Here, we analyzed the fast-twitch muscle of juvenile Piaractus mesopotamicus (pacu) submitted to prolonged fasting (30d) and refeeding (6h, 24h, 48h and 30d). We measured the relative rate of weight and length increase (RRI_length and RRI_weight), performed shotgun proteomic analysis and did Western blotting for PVALB after 30d of fasting and 30d of refeeding. We assessed the gene expression of igf-1, mafbx and pvalb after 30d of fasting and after 6h, 24h, 48h and 30d of refeeding. We performed a bioinformatic analysis to predict miRNAs that possibly control parvalbumin expression. After fasting, RRI_length, RRI_weight and igf-1 expression decreased, while the mafbx expression increased, which suggest that prolonged fasting caused muscle atrophy. After 6h and 24h of refeeding, mafbx was not changed and igf-1 was downregulated, while after 48h of refeeding mafbx was downregulated and igf-1 was not changed. After 30d of refeeding, RRI_length and RRI_weight were increased and igf-1 and mafbx expression were not changed. Proteomic analysis identified 99 proteins after 30d of fasting and 71 proteins after 30d of refeeding, of which 23 and 17, respectively, were differentially expressed. Most of these differentially expressed proteins were related to cytoskeleton, muscle contraction, and metabolism. Among these, parvalbumin (PVALB) was selected for further validation. The analysis showed that pvalb mRNA was downregulated after 6h and 24h of refeeding, but was not changed after 30d of fasting or 48h and 30d of refeeding. The Western blotting confirmed that PVALB protein was downregulated after 30d of fasting and 30d of refeeding. The downregulation of the protein and the unchanged expression of the mRNA after 30d of fasting and 30d of refeeding suggest a post-transcriptional regulation of PVALB. Our miRNA analysis predicted 444 unique miRNAs that may target pvalb. In conclusion, muscle atrophy and partial compensatory growth caused by prolonged fasting followed by refeeding affected the muscle proteome and PVALB expression.

Molecular characterization of B-cell epitopes for the major fish allergen, parvalbumin, by shotgun proteomics, protein-based bioinformatics and IgE-reactive approaches

Parvalbumins beta (β-PRVBs) are the main fish allergens. The only proven and effective treatment for this type of hypersensitivity is to consume a diet free of fish. We present the molecular characterization of B-cell epitopes by shotgun proteomics of different β-PRVBs combined with protein-based bioinformatics and IgE-reactive approaches. The final goal of this work is to identify potential peptide vaccine candidates for fish allergy. Purified β-PRVBs from the main fifteen different fish species that cause allergy were analyzed by shotgun proteomics. Identified β-PRVBs peptide sequences and ninety-eight β-PRVB protein sequences from UniProtKB were combined, aligned and analyzed to determine B-cell epitopes using the Kolaskar and Tongaonkar algorithm. The highest rated predicted B-cell peptide epitopes were evaluated by ELISA using the corresponding synthetic peptides and sera from healthy and fish allergic patients. A total of 35 peptides were identified as B-cell epitopes. The top B-cell peptide epitopes (LKLFLQV, ACAHLCK, FAVLVKQ and LFLQNFV) that may induce protective immune responses were selected as potential peptide vaccine candidates. The 3D model of these peptides were located in the surface of the protein. This study provides the global characterization of B-cell epitopes for all β-PRVBs sequences that will facilitate the design of new potential immunotherapies. SIGNIFICANCE: This work provides the global characterization of B-cell epitopes for all β-PRVBs sequences by Shotgun Proteomics combined with Protein-based Bioinformatics and IgE-reactive approaches. This study will increase our understanding of the molecular mechanisms whereby fish allergens elicit allergic reactions and will facilitate the design of new potential peptide vaccine candidates.

Diagnosis of fish and shellfish allergies

Seafood allergy is a hypersensitive disorder with increasing prevalence worldwide. Effective and accurate diagnostic workup for seafood allergy is essential for clinicians and patients. Parvalbumin and tropomyosin are the most common fish and shellfish allergens, respectively. The diagnosis of seafood allergies is complicated by cross-reactivity among fish allergens and between shellfish allergens and other arthropods. Current clinical diagnosis of seafood allergy is a complex algorithm that includes clinical assessment, skin prick test, specific IgE measurement, and oral food challenges. Emerging diagnostic strategies, such as component-resolved diagnosis (CRD), which uses single allergenic components for assessment of epitope specific IgE, can provide critical information in predicting individualized sensitization patterns and risk of severe allergic reactions. Further understanding of the molecular identities and characteristics of seafood allergens can advance the development of CRD and lead to more precise diagnosis and improved clinical management of seafood allergies.

Seafood allergy: A comprehensive review of fish and shellfish allergens

Seafood refers to several distinct groups of edible aquatic animals including fish, crustacean, and mollusc. The two invertebrate groups of crustacean and mollusc are, for culinary reasons, often combined as shellfish but belong to two very different phyla. The evolutionary and taxonomic diversity of the various consumed seafood species poses a challenge in the identification and characterisation of the major and minor allergens critical for reliable diagnostics and therapeutic treatments. Many allergenic proteins are very different between these groups; however, some pan-allergens, including parvalbumin, tropomyosin and arginine kinase, seem to induce immunological and clinical cross-reactivity. This extensive review details the advances in the bio-molecular characterisation of 20 allergenic proteins within the three distinct seafood groups; fish, crustacean and molluscs. Furthermore, the structural and biochemical properties of the major allergens are described to highlight the immunological and subsequent clinical cross-reactivities. A comprehensive list of purified and recombinant allergens is provided, and the applications of component-resolved diagnostics and current therapeutic developments are discussed.

A major allergen in rainbow trout (Oncorhynchus mykiss): complete sequences of parvalbumin by MALDI tandem mass spectrometry

Fish parvalbumin (PRVB) is an abundant and stable protein in fish meat. The variation in cross-reactivity among individuals is well known and explained by a broad repertoire of molecular forms and differences between IgE-binding epitopes in fish species. PVRB has "sequential" epitopes, which retain their IgE-binding capacity and allergenicity also after heating and digestion using proteolytic enzymes. From the allergonomics perspective, PRVB is still a challenging target due to its multiple isoforms present at different degrees of distribution. Little information is available in the databases about PVRBs from Oncorhynchus mykiss. At present, only two validated, incomplete isoforms of this species are included in the protein databases: parvalbumin beta 1 (P86431) and parvalbumin beta 2 (P86432). A simple and rapid protocol has been developed for selective solubilization of PRVB from the muscle of farmed rainbow trout (Oncorhynchus mykiss), followed by calcium depletion, proteolytic digestion, MALDI MS, and MS/MS analysis. With this strategy thermal allergen release was assessed and PRVB1 (P86431), PRVB1.1, PRVB2 (P86432) and PRVB2.1 variants from the rainbow trout were sequenced. The correct ordering of peptide sequences was aided by mapping the overlapping enzymatic digests. The deduced peptide sequences were arranged and the theoretical molecular masses (Mr) of the resulting sequences were calculated. Experimental masses (Mr) of each PRVB variant were measured by linear MALDI-TOF.

A Cross-Reactive Human Single-Chain Antibody for Detection of Major Fish Allergens, Parvalbumins, and Identification of a Major IgE-Binding Epitope

Fish allergy is associated with moderate to severe IgE-mediated reactions to the calcium binding parvalbumins present in fish muscle. Allergy to multiple fish species is caused by parvalbumin-specific cross-reactive IgE recognizing conserved epitopes. In this study, we aimed to produce cross-reactive single chain variable fragment (scFv) antibodies for the detection of parvalbumins in fish extracts and the identification of IgE epitopes. Parvalbumin-specific phage clones were isolated from the human ETH-2 phage display library by three rounds of biopanning either against cod parvalbumin or by sequential biopanning against cod (Gad m 1), carp (Cyp c 1) and rainbow trout (Onc m 1) parvalbumins. While biopanning against Gad m 1 resulted in the selection of clones specific exclusively for Gad m 1, the second approach resulted in the selection of clones cross-reacting with all three parvalbumins. Two clones, scFv-gco9 recognizing all three parvalbumins, and scFv-goo8 recognizing only Gad m 1 were expressed in the E. coli non-suppressor strain HB2151 and purified from the periplasm. scFv-gco9 showed highly selective binding to parvalbumins in processed fish products such as breaded cod sticks, fried carp and smoked trout in Western blots. In addition, the scFv-gco9-AP produced as alkaline phosphatase fusion protein, allowed a single-step detection of the parvalbumins. In competitive ELISA, scFv-gco9 was able to inhibit binding of IgE from fish allergic patients’ sera to all three β-parvalbumins by up to 80%, whereas inhibition by scFv-goo8 was up to 20%. ¹H/¹⁵N HSQC NMR analysis of the rGad m 1:scFv-gco9 complex showed participation of amino acid residues conserved among these three parvalbumins explaining their cross-reactivity on a molecular level. In this study, we have demonstrated an approach for the selection of cross-reactive parvalbumin-specific antibodies that can be used for allergen detection and for mapping of conserved epitopes.

Fish allergy: in review

Globally, the rising consumption of fish and its derivatives, due to its nutritional value and divergence of international cuisines, has led to an increase in reports of adverse reactions to fish. Reactions to fish are not only mediated by the immune system causing allergies, but are often caused by various toxins and parasites including ciguatera and Anisakis. Allergic reactions to fish can be serious and life threatening and children usually do not outgrow this type of food allergy. The route of exposure is not only restricted to ingestion but include manual handling and inhalation of cooking vapors in the domestic and occupational environment. Prevalence rates of self-reported fish allergy range from 0.2 to 2.29 % in the general population, but can reach up to 8 % among fish processing workers. Fish allergy seems to vary with geographical eating habits, type of fish processing, and fish species exposure. The major fish allergen characterized is parvalbumin in addition to several less well-known allergens. This contemporary review discusses interesting and new findings in the area of fish allergy including demographics, novel allergens identified, immunological mechanisms of sensitization, and innovative approaches in diagnosing and managing this life-long disease.

Immunological cross-reactivity between four distant parvalbumins-Impact on allergen detection and diagnostics

Fish are the largest and most diverse group of vertebrates. Fish are also a part of the eight food groups that cause the majority of IgE mediated food reactions. Detection tools for fish allergens are however limited due to the great diversity of fish species, despite fish allergy and its major allergen parvalbumin being well documented. The most commonly studied fish are frequently consumed in North America and Europe. However, much less is known about fish allergens in the Australasian region although fish is widely consumed in this region. A comprehensive phylogenetic analysis was performed of known parvalbumin amino acid sequences to determine possible candidate antigens for new cross-reactive antibodies to be used to detect most fish parvalbumins. Polyclonal rabbit antibodies were raised against parvalbumins from frequently consumed barramundi (Lates calcarifer), basa (Pangasius bocourti), pilchard (Sardinops sagax) and Atlantic salmon (Salmo salar). These were evaluated for cross-reactivity against a panel of 45 fish extracts (raw, heated and canned fish). Anti-barramundi parvalbumin proved to be the most cross-reactive antibody, detecting 87.5% of the 40 species analyzed, followed by anti-pilchard and anti-basa antibody. In contrast the anti-salmon antibody was very specific and only reacted to salmonidae and a few other fish. All analyzed fish species, except mahi mahi, swordfish, yellowfin tuna and all 5 canned fish had parvalbumin detected in raw extracts. However antibody reactivity to many fish was heat liable or susceptible to denaturation, demonstrating that some parvalbumins have most likely conformational epitopes, which lose antibody reactivity after heat treatment. We have demonstrated the generation of highly cross-reactive anti-parvalbumin antibodies that could be used for the detection of allergenic fish parvalbumin in contaminated food products. This cross-reactivity study thus shows processing of fish, especially canning, can have on impact on antibody recognition by ELISA, possibly similar to IgE-binding in vivo.

Purification and characterization of parvalbumin isotypes from grass carp (Ctenopharyngodon idella)

The prevalence of fish allergy is rapidly increasing because of a growing fish consumption driven mainly by a positive image of the fish and health relationship. The purpose of this study was to characterize parvalbumin isotypes from grass carp (Ctenopharyngodon idella), one of the most frequently consumed freshwater fish in China. Three parvalbumin isotypes were purified using consecutive gel filtration and reverse-phase chromatography and denoted as PVI, PVII, and PVIII. The molecular weights of the isotypes were determined to be 11.968, 11.430, and 11.512 kDa, respectively. PVI showed 74% matched amino acids sequence with PV isotype 4a from Danio rerio, while PVII and PVIII showed 46% matched amino acids sequence with PV isotypes from Hypophthalmichthys molitrix. PVII is the dominant allergen, but it was liable to gastrointestinal enzymes as PVIII; however, PVI was resistant to pepsin digestion. A further study is to characterize the epitopes of PVII, the dominant allergen.

Rapid direct detection of the major fish allergen, parvalbumin, by selected MS/MS ion monitoring mass spectrometry

Parvalbumins beta (β-PRVBs) are considered the major fish allergens. A new strategy for the rapid and direct detection of these allergens in any foodstuff is presented in this work. The proposed methodology is based on the purification of β-PRVBs by treatment with heat, the use of accelerated in-solution trypsin digestion under an ultrasonic field provided by High-Intensity Focused Ultrasound (HIFU) and the monitoring of only nineteen β-PRVB peptide biomarkers by Selected MS/MS Ion Monitoring (SMIM) in a linear ion trap (LIT) mass spectrometer. The present strategy allows the direct detection of the presence of fish β-PRVBs in any food product in less than 2 hours.

Evaluation and comparison of the species-specificity of 3 antiparvalbumin IgG antibodies

Parvalbumin is a pan-allergen in fish and frogs that triggers IgE-mediated reactions in fish-allergic individuals. Previous studies demonstrated that antibodies raised against fish and frog parvalbumins displayed varying specificity for different fish species, and thus, the applicability of these antibodies for potential use in immunoassays to detect fish residues were limited. We aimed to determine the specificity of 3 IgG antibodies for various fish species. Indirect enzyme-linked immunosorbent assay (ELISA) and IgG-immunoblotting were used to compare the reactivity of the polyclonal anticod parvalbumin antibody and the commercially available, monoclonal antifrog and monoclonal anticarp parvalbumin antibodies against raw muscle extracts of 29 fish species. All antibodies demonstrated varying specificities for different fish species. Of the 3 antibodies, the polyclonal anticod parvalbumin antibody is the most suitable for the detection of fish parvalbumins as it showed reactivity to the widest range of species, including herring, pilchard, carp, pike, cod, pollock, haddock, cusk, hake, bluegill, tilapia, bass, grouper, trout, catfish, and perch, although detection was still limited for several key fish species.

Monoclonal antibody based immunodot for specific detection of proteins of the shrimp Penaeus species

Frozen shrimp continued to be the single largest item of export from India in terms of value accounting for about 44% of the total marine export earnings. Headless, peeled frozen shrimp is a common and dominant item in the market and there is need for differentiating peeled Penaeus sp from Metapenaeus, Parapenopsis and Macrobrachium sp as consumer preference and price vary. Furthermore, there is need to find out original species used in value addition of shrimp products. Hence, it is essential for development of simple and consumer friendly technique for the identification of shrimp and their products in the market. Two monoclonal antibodies (MAbs) C-15 (IgG3) and C-52 (IgG2a) reacting with 65 and 47 kD proteins of Penaeus monodon respectively in the Western blot were selected. In epitope analysis by immunodot, the two MAbs reacted and recognized specific proteins of P. monodon, Fenneropenaeus indicus and Littopenaeus vannamei and not that of Metapenaeus, Parapenopsis, Macrobrachium rosenbergii, crabs and fishes. The immunodot required 120 min for completion. The sensitivity of the immunodot to detect proteins of P. monodon was 0.225 mg with MAb C-15 and 0.028 mg with MAb C-52. The MAb based immunodot developed, could be used for identifying and differentiating meat of P. monodon, F. indicus, and L. vannamei from that of Metapenaeus, Parapenopsis, M. rosenbergii, crabs and fishes.

Preparation of a monoclonal antibody and development of an indirect competitive ELISA for the detection of chlorpromazine residue in chicken and swine liver

BACKGROUND

Chlorpromazine is a typical antipsychotic drug used to make food-producing animals calm and promote growth as feed additives. Accumulation of chlorpromazine in animal bodies would cause side effects in the circulatory and nervous systems, and have adverse effects on blood cells, the skin and the eye. To detect the chlorpromazine residue in food producing animals, an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed based on preparation of an anti-chlorpromazine monoclonal antibody.

RESULTS

The antibody generated from immunogen of cationic bovine serum albumin (cBSA) coupled with chlorpromazine showed high sensitivity toward chlorpromazine with an IC(50) value of 0.73 ppb. The ELISA method was applied to detect swine liver and chicken samples spiked by chlorpromazine and satisfactory results were obtained. The recovery rates in chicken and swine liver were in the range of 88-95% and 86-95%, respectively; the intra-assay coefficients of variation were both < 15.3% and < 13.5%, respectively.

CONCLUSION

An indirect competitive ELISA method based on a monoclonal antibody towards chlorpromazine with excellent sensitivity and specificity has been successfully developed. The immunoassay provided in this study was a hopeful alternative to chromatography spectrometry for regulatory analysis of chlorpromazine residue in food-producing animals.