Allergy information for: Lobster (Homarus americanus)

Name: Lobster
Scientific Name: Homarus americanus
Occurrence: Generally eaten as cooked lobster but also in mixed seafood dishes such as paella.
Allergy Information:
Lobsters along with crabs, crayfish, and shrimps are crustaceans. Food allergy to crustaceans is relatively common, symptoms ranging from mild oral allergy to severe symptoms such as anaphylaxis. Cooking does not remove the allergen. Crustacea are the third most important cause of food induced anaphylaxis after peanuts and tree nuts (cashews, almonds, pecans, walnuts, etc.). Thus crustacea and products thereof are listed in annex IIIa of the EU directive on labelling of foods and must be labelled when used as ingredients in pre-packaged food.
Most allergy to crustacea seems to involve a muscles protein called tropomyosin, which is very similar in a wide range of crustacean foods. As a result someone with allergy to tropomyosin from one kind of crustacean is likely to react to others. Thus individuals with allergy to one kind of crustacean are usually advised to avoid all types of crustacean foods.
In addition, some individuals with allergies to insects such as cockroach or moths can suffer food allergy to crustacean foods. Whilst most individuals with allergy to shrimps (crustacea) can tolerate molluscs, individuals with allergy to both types of shellfish have been reported. However, individuals allergic to finfish (such as cod or salmon) do not generally have allergies to shellfish.

Supplementary information on Shrimps and other crustaceans Allergy
Crustaceans are among the most commonly consumed seafoods. Crustaceans belong to the Arthropod family. Crustaceans are divided into six major subgroups that include 44,000 species. Amongst these is a variety of commonly and less commonly eaten sea foods like langoustine, lobster, crayfish, and crab. Other sea foods like clams, mussels, oysters, scallops, abalone and squid are no crustaceans but molluscs or shell fish. Crustacean allergy is a so-called IgE-mediated food allergy. IgE (Immunoglobulin E) is the allergy antibody.
Symptoms
Reactions range from mild oral allergy syndrome (itching of the lips, mouth, or throat, and swelling of the lips, tongue, throat, and palate) to life-threatening systemic anaphylaxis (difficulty breathing, drop in blood pressure, and even death). Symptoms occur within one to one hour of ingestion (90% of cases). However, urticaria (hives) is the most frequent symptom. Others symptoms affecting the skin (itching, swelling), gastro-intestinal tract (nausea, cramping heartburn, and diarrhoea), respiratory symptoms (asthma, hayfever), and eyes (conjunctivitis) have been reported. Shellfish are frequently implicated in fatal anaphylactic reactions and are the third most important cause of anaphylaxis after peanuts and tree nuts (cashews, almonds, pecans, walnuts, etc.).
Symptoms most often occur when the seafood is ingested (generally require higher doses to elicit a reaction), but can also appear when raw seafood is handled and even after inhaling steam while crustaceans such as shrimp are being cooked (may cause respiratory reactions). Cooking oil contaminated with seafood residues has also been reported to cause adverse reactions. Allergic reactions in workers at every stage of seafood processing also occur and are a serious public health problem in countries with major shellfish industries.
Related foods (cross-reactions)
It has been estimated that 75% of individuals who are allergic to one type of crustacean (shrimp, lobster, crawfish, or crab) are also allergic to another type. This is referred to as cross-reactivity. Cross-reactions between crustaceans and molluscs (oysters, squid, scallops) are also possible involving the same type of proteins in these foods. In fact, the molecules responsible for the cross-reactions can also cause cross-reactions between crustaceans, dust mites, cockroaches, and chironomid (used as fish food). However, no cross-reactions have been reported between crustaceans and fish such as Pollock, salmon, tuna, mackerel, trout, and anchovies.
Who, when, how long and how often?
Food allergies are most frequent in children, but adults are not exempt. Crustaceans, peanuts, fish, and tree nuts are the most common causes of food allergies among adults. Fish and shellfish allergies are estimated to affect approximately 1% of the general population. Countries where large amounts of crustaceans are consumed, such as the Scandinavian countries, have higher rates of crustacean allergies, although no species-specific studies have been conducted. Little is known about their persistence, but all evidence indicates that crustacean allergies are usually not outgrown.
How much is too much?
Symptoms most often occur when the seafood is ingested (generally require higher doses to elicit a reaction), but can also appear when raw seafood is handled and even after inhaling steam while crustaceans such as shrimp are being cooked (may cause respiratory reactions). Cooking oil contaminated with seafood residues has also been reported to cause adverse reactions. Allergic reactions in workers at every stage of seafood processing also occur and are a serious public health problem in countries with major shellfish industries.
While one shrimp is often enough to induce an allergic reaction, some people react to even smaller amounts. Lowest threshold dosages remain to be elucidated.
Diagnosis
A detailed patient history is first taken. Skin and laboratory tests are then used to help eliminate allergic foods from the diet. In the case of crustaceans, a positive skin test combined with elevated antibody levels allow shrimp allergies, for example, to be diagnosed with 87% certainty. There is no established threshold value for crustacean specific IgE.
However, food challenges (giving increasing amounts of potentially allergic food in graduated steps to patients to determine whether they will have an allergic reaction) are the most effective way of determining whether a person is truly allergic to a certain food. Initial food challenges are always conducted as double-blind, placebo controlled tests. In the case of crustaceans, for example, food challenges involve double-blind, placebo-controlled tests using increasing doses of the boiled crustacean in vanilla ice cream containing grape flavouring. If the double-blind placebo-controlled food challenge is negative, an open food challenge is generally performed. Food challenges should only be performed in a hospital setting with highly trained personnel used to dealing with anaphylactic reactions. Patients with a recent history of severe reactions should not be challenged. In addition, patients that are allergic to one type of crustacean should be tested for allergies reactions to all the other crustaceans because of the potential for cross-reactions.
Where do I find crustacean?
Crustaceans or crustacean residues may be present in certain processed foods. It is thus very important that people with allergies to crustaceans develop the habit of carefully reading ingredient labels and be aware of the words, terms, and indicators used on labels that indicate the presence of crustaceans or crustacean residues. Food products can contain hidden allergens.
Non-food products
Crustaceans are used in few non-food products such as creams. Contact with these products can induce allergic reactions.
Avoidance
For patients diagnosed with a crustacean allergy, avoidance of crustaceans is the only proven therapy, especially since adverse reactions to very small amounts of crustaceans are not uncommon. It is thus very important that people with allergies to crustaceans develop the habit of carefully reading ingredient labels and that they are aware of words, terms, and indicators used on labels that indicate the presence of crustaceans or crustacean residues. Food products can contain hidden allergens. Eating out especially in restaurants with South-East Asian cuisine is a risk factor for unexpected contact with crustaceans. Annex IIIa of the new EU labelling directive makes the listing of crustaceans and crustacean products on labels mandatory.
Other Information:
Crustacea and products thereof are listed in annex IIIa of the EU directive on labelling of foods. Crustacea include shrimps, crabs, crayfish, and lobsters.
This entry includes data on several species of lobsters and crawfish. There are two allergens with protein sequences which are tropomyosins from different species.
The image of a cooked lobster is taken with permission from the Lobster Project: http://www.src.le.ac.uk/lobster
Taxonomic Information:
Lobsters and crayfishes are decapodes and like crabs and many shrimps are believed to have evolved from a Devonian shrimp-like ancestor. Several species of the Astacidea, true lobsters and crayfishes, have been mentioned in publications on allergy including:
1. The American lobster, Homarus americanus, NEWT 6706, ITIS 97314;
2. The European lobster, Homarus gammarus, NEWT 6707;
3. The Norway lobster, Nephrops norvegicus, NEWT 6829;
4. The red swamp crayfish, Procambarus clarkii, NEWT 6728.
The suborder Pleocyemata includes Astacidea and also Palinura which includes spiny lobsters. The spiny lobsters mentioned as allergenic food include
1. Panulirus stimpsoni, NEWT 71578;
2. Panulirus homarus, NEWT 150425;
3. Panulirus argus, NEWT 6737.
An alternative grouping to that from NEWT or ITIS is given by http://tolweb.org/tree?group=Decapoda.
Last modified: 18 October 2006

Reviews (0)

References (0)

Clinical History

Number of Studies:1-5
Number of Patients:21-50
Symptoms:As patients almost always react to shrimps, crawfish, lobsters and crabs, there are no reports of reactions specifically after eating lobsters. Halmepuro et al (1987) [1802] describe the 23 patients who donated sera as having analphylactic, gasterointestinal or respiratory reactions to crustacea.

Skin Prick Test

Number of Studies:1-5
Food/Type of allergen:
Halmepuro et al. (1987) [1802] made extracts from crawfish (Procambarus clarkii), spiny Lobster (panuliris argus), white shrimp (Litopenaeus setiferus) and blue crab (Callinectes sapidus) which were boiled for 15 minutes, peeled and homogenized in approximately 2 ml/g of phosphate buffered saline, pH 7.2 (PBS). After mixing overnight at 4°C, the extract was centrifuged at 16000 x g for 30 minutes at 4°C. Supernatants were concentated by ultrafiltration with an Amicon YM2 (cut-off 2 kda) and exhausively dialysed against PBS with a 3.5 kDa membrane. The extract was centrifuged at 66000 x g for 30 minutes at 4°C and the supernatant aliquoted and stored at -20°C. A maximum of 10 mg/ml extract was used.
Protocol: (controls, definition of positive etc)Halmepuro et al. (1987) [1802] defined a positive SPT as giving a wheal of 2 mm greater diameter than the negative control.
Number of Patients:
Halmepuro et al (1987) [1802] reported testing 23 patients.
Summary of Results:Halmepuro et al (1987) [1802] reported that all 23 patients gave a positive skin prick with lobster and crawfish.

IgE assay (by RAST, CAP etc)

Number of Studies:0
Food/Type of allergen:
Halmepuro et al. (1987) [1802] made extracts from crawfish (Procambarus clarkii), spiny Lobster (panuliris argus), white shrimp (Litopenaeus setiferus) and blue crab (Callinectes sapidus) which were boiled for 15 minutes, peeled and homogenized in approximately 2 ml/g of phosphate buffered saline, pH 7.2 (PBS). After mixing overnight at 4°C, the extract was centrifuged at 16000 x g for 30 minutes at 4°C. Supernatants were concentated by ultrafiltration with an Amicon YM2 (cut-off 2 kda) and exhausively dialysed against PBS with a 3.5 kDa membrane. The extract was centrifuged at 66000 x g for 30 minutes at 4°C and the supernatant aliquoted and stored at -20°C. Lehrer & McCants (1987) [1575] made similar extracts including oyster with the a final centrifugation at 78000 x g.
IgE protocol:
Halmepuro et al. (1987) [1802] used RAST and crossed-immune electrophoresis (CRIE).
Lehrer & McCants (1987) [1575] used RAST and RAST inhibition.
Leung et al. (1996) [1557] and Leung et al (1998) [1555] used immunoblotting.
Number of Patients:
Halmepuro et al. (1987) [1802] tested 23 sera.
Leung et al. (1996) [1557] used sera from 9 shrimp allergic subjects.
Leung et al (1998) [1555] used sera from 10 crustacea allergic subjects.
Summary of Results:
Halmepuro et al. (1987) [1802] reported that all 23 sera were positive by RAST (>18% of added radioactivity) with lobster and crawfish. CRIE suggested that the allergens of shrimp, crawfish and lobster were similar.
Lehrer & McCants (1987) [1575] reported a strong correlation between RAST results for oyster and crustacea (0.82 for lobster). Raw and cooked oyster were inhibited to 85% and 89% by lobster extract (see oyster for further information).

Immunoblotting

Immunoblotting separation:Leung et al (1996) [1557] separated the extracts by SDS-PAGE in a 10% separating gel with a 5% stacking gel. Samples were boiled for 10 minutes in buffer with 4% SDS, 10% 2-mercaptoethanol before loading.
Immunoblotting detection method:Leung et al (1996) [1557] electrophoretically transferred proteins onto a nitrocellulose filter in a semi-dry transfer cell (Bio-Rad) at 15 V for 1 hour. Strips of the blot were blocked with 3% (w/v) nonfat dried milk in PBS for 30 minutes. Strips were incubated in the test serum (1:10 dilution) in PBS with 3% milk at 4°C overnight with shaking. The strip was washed in PBS-Tween (0.05% Tween-20 in PBS) at room temperature three times for 20 minutes each. The bound IgE on the strip was detected by incubation with ¹²⁵I-labeled anti-human IgE (Sanofi-Pasteur Diagnostics, Ohaska, Minn.) in PBS buffer with 3% milk at 4°C overnight. Nonspecific binding was removed by washing the strip with PBS-Tween at room temperature three times for 20 minutes. The strips were exposed to x-ray film with an intensifying screen from 24 hours to 1 week at -70°C.
Immunoblotting results:
Leung et al. (1996) [1557] reported that 9/9 sera from shrimp allergic patients bound to an allergen from Panuliris homarus at 38 kDa (see greasybacked shrimp entry).
Leung et al (1998) [1555] reported that the recombinant Hom a 1, rPan s 1 and rMet e 1 ran as 60 kDa GST-fusion proteins and bound IgE from sera from 10 crustacea allergic subjects.

Oral provocation

Number of Studies:0
Food used and oral provocation vehicle:
Blind:
Number of Patients:
Dose response:
Symptoms:No challenges with lobster reported

IgE cross-reactivity and Polysensitisation

Leung et al. (1996) [1557], Leung et al (1998) [1555], Leung et al (1998) [1554] and DeWitt et al. (2004) [1536] report details of the similar tropomyosin allergens from shrimps, lobsters and crabs together with IgE cross-reactivity between both extracts and recombinant allergens. Several molluscs are also shown to have cross-reactive tropomyosins.

Halmepuro et al. (1987) [1802] had earlier reported IgE cross-reactivity between extracts from crustacea and Lehrer & McCants (1987) [1575] extended this to oysters.

Other Clinical information

Binder et al (2001) [1588] reported that immunoblots of an extract of lobster (H. gammarus) show IgE binding near 40 kDa using sera of individuals allergic to the indianmeal moth. This was inhibited by preincubation of the sera with recombinant indianmeal moth arginine kinase. Thus arginine kinase may also be a lobster allergen.

Crustacea have been frequently reported as occupational allergens. Several species in addition to those mentioned in articles on food allergy have been reported as occupational allergens including snow crabs (Cartier et al, 1986 [1591]; Cartier et al, 2004 [1610]), Nephrops norvegicus or scampi (Griffin et al, 2001 [1611]) and gammarus shrimps (Fontan et al. 2005 [1765]; Baur et al. 2000 [1550]). Occupational allergy probably involves aerosols (Bang et al. 2005 [1767]; Goetz & Whisman, 2000 [1594]; Desjardins et al 1995 [1561]) and both the stability of tropomyosins in boiling water (Lehrer et al. 1990 [1607]) and their cross-reactivity may be significant. Other allergens such as the 97 kDa allergen of scampi are also stable as aerosols (Griffin et al, 2001 [1611]). Nephrops is relatively closely related to Homarus which may produce similar allergens. Contact determatis has also been reported (Aasmoe et al, 2005 [1766]; Scharer et al, 2002 [1612]).

Reviews (3)

Chu KH, Tang CY, Wu A, Leung PS.
Seafood allergy: lessons from clinical symptoms, immunological mechanisms and molecular biology.
Adv Biochem Eng Biotechnol. 97:205-235.. 2005
PUBMEDID: 16261809
Lehrer SB, Ayuso R, Reese G.
Seafood allergy and allergens: a review.
Mar Biotechnol (NY). 5(4):339-348.. 2003
PUBMEDID: 14719162
Lehrer SB, Ayuso R, Reese G.
Current understanding of food allergens
Ann N Y Acad Sci. 964:69-85.. 2002
PUBMEDID: 12023195

References (14)

Binder M, Mahler V, Hayek B, Sperr WR, Scholler M, Prozell S, Wiedermann G, Valent P, Valenta R, Duchene M.
Molecular and immunological characterization of arginine kinase from the Indianmeal moth, Plodia interpunctella, a novel cross-reactive invertebrate pan-allergen.
J Immunol. 167(9):5470-5477.. 2001
PUBMEDID: 11673567
Halmepuro L, Salvaggio JE, Lehrer SB.
Crawfish and lobster allergens: identification and structural similarities with other crustacea.
Int Arch Allergy Appl Immunol. 1987;84(2):165-172.. 1987
PUBMEDID: 3654002
Cartier A, Malo JL, Ghezzo H, McCants M, Lehrer SB.
IgE sensitization in snow crab-processing workers.
J Allergy Clin Immunol. 78(2):344-348. . 1986
PUBMEDID: 3734286
Cartier A, Lehrer SB, Horth-Susin L, Swanson M, Neis B, Howse D, Jong M.
Prevalence of crab asthma in crab plant workers in Newfoundland and Labrador.
Int J Circumpolar Health 63 Suppl 2:333-336.. 2004
PUBMEDID: 15736679
Griffin P, Allan L, Gibson M, Elms J, Wiley K, Curran AD.
Measurement of personal exposure to aerosols of Nephrops norvegicus (scampi) using a monoclonal-based assay.
Clin Exp Allergy 31(6):928-933.. 2001
PUBMEDID: 11422159
Scharer L, Hafner J, Wuthrich B, Bucher C.
Occupational protein contact dermatitis from shrimps. A new presentation of the crustacean-mite syndrome.
Contact Dermatitis. 46(3):181-182.. 2002
PUBMEDID: 12000333
Goetz DW, Whisman BA.
Occupational asthma in a seafood restaurant worker: cross-reactivity of shrimp and scallops.
Ann Allergy Asthma Immunol. 85(6 Pt 1):461-466.. 2000
PUBMEDID: 11152166
Desjardins A, Malo JL, L'Archeveque J, Cartier A, McCants M, Lehrer SB.
Occupational IgE-mediated sensitization and asthma caused by clam and shrimp.
J Allergy Clin Immunol. 96(5 Pt 1):608-617.. 1995
PUBMEDID: 7499677
Aasmoe L, Bang B, Andorsen GS, Evans R, Gram IT, Lochen ML.
Skin symptoms in the seafood-processing industry in north Norway.
Contact Dermatitis 52(2):102-107.. 2005
PUBMEDID: 15725289
Bang B, Aasmoe L, Aamodt BH, Aardal L, Andorsen GS, Bolle R, Boe R, Van Do T, Evans R, Florvag E, Gram IT, Huser PO, Kramvik E, Lochen ML, Pedersen B, Rasmussen T.
Exposure and airway effects of seafood industry workers in northern Norway.
J Occup Environ Med. 2005 May;47(5):482-492.. 2005
PUBMEDID: 15891527
Lehrer SB, McCants ML, Salvaggio JE.
Identification of crustacea allergens by crossed radioimmunoelectrophoresis.
Int Arch Allergy Appl Immunol. 77(1-2):192-194.. 1985
PUBMEDID: 4008073
DeWitt AM, Mattsson L, Lauer I, Reese G, Lidholm J.
Recombinant tropomyosin from Penaeus aztecus (rPen a 1) for measurement of specific immunoglobulin E antibodies relevant in food allergy to crustaceans and other invertebrates.
Mol Nutr Food Res. 48(5):370-379.. 2004
PUBMEDID: 15672477
Leung PS, Chow WK, Duffey S, Kwan HS, Gershwin ME, Chu KH.
IgE reactivity against a cross-reactive allergen in crustacea and mollusca: evidence for tropomyosin as the common allergen.
J Allergy Clin Immunol. 98(5 Pt 1):954-961.. 1996
PUBMEDID: 8939159
Leung PS, Chen YC, Mykles DL, Chow WK, Li CP, Chu KH.
Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen.
Mol Mar Biol Biotechnol. 7(1):12-20.. 1998
PUBMEDID: 9597774

Biochemical Information for Hom a 1

Allergen Name:Hom a 1
Alternatve Allergen Names:Tropomyosin
Allergen Designation:Major
Protein Family:Pfam PF00261; Tropomyosin family
Sequence Known?:Yes
Allergen accession No.s:http://us.expasy.org/cgi-bin/niceprot.pl?O44119 (O44119 translates AF034953; AAC48287.1)
There is a splice isoform O44119-2 which translates AF034954; AAC48288.1.
3D Structure Accession No.:N/A
Calculated Masses:32907 Da
Experimental Masses:
34 kDa (Pan s 1 from Panuliris stimpsoni, Leung et al. 1998 [1555]).
36 kDa (tropomyosin from Panuliris argus, Musmand et al. 1993 [1707]).
38 kDa (tropomyosin from Panuliris homarus, Leung et al. 1996 [1557]).
Oligomeric Masses:
Tropomyosins form dimers.
Allergen epitopes:Not known for Hom a 1. However, the data on shrimp allergens Pen a 1 and Pen i 1 is likely to be relevant because of cross-reactivity.
Allergen stability:
Process, chemical, enzymatic:The allergenicity of crustacea can survive cooking, possibly because tropomyosin have a very simple helical structure which can rapidly refold after denaturation. Extracts from boiled crustacea are frequently used in allergen purification and for extract preparation.
Nature of main cross-reacting proteins:
Leung et al (1998) [1555] reported the cloning of tropomyosins from Homarus americanus, Hom a 1, and Panulirus stimpsoni, Pan s 1. The sequence from Panulirus stimpsoni has 271/274 (98%) residues identical to the splice isoform O44119-2 from Homarus americanus. Leung et al (1998) [1555] reported that binding of IgE from sera from 10/10 crustacean allergic subjects to lobster extracts was inhibited by rMet e 1, rPan s 1 or rHom a 1.
Leung et al (1998) [1554] reported the percentage of amino acid identity of crab Cha f 1 with Met e 1, lobster Pan s 1 and Hom a 1 and Homarus americanus slow muscle, fruit fly and chicken tropomyosins as 90%, 91%, 92%, 96%, 69% and 60% respectively. They found that IgE from the sera from 10/10 crab allergic subjects bound rMet e 1, rPan s 1 and rHom a 1.
DeWitt et al. (2004) [1536] report that the level of sequence identity of tropomyosins with Pen a 1 is 99% for lobster (Homarus americanus), 92% for crab (Charybdis feriatus), 78-82% for insects and dust mites, 71% for a nematode (Caenorhabditis elegans) and 57% for both blue mussel (Mytilus edulis) and human, suggesting that IgE cross-reactivity is very likely for the invertebrate tropomysosins. DeWitt et al. (2004) [1536] also showed specific IgE binding to recombinant Pen a 1 and seven invertebrate extracts with 9 sera. 6 sera bound extracts from crustacea most strongly, 2 bound dust mite extract more strongly and one serum showed similar binding with both extracts. rPen a 1 bound 94% of the IgE from the 6 crustacea specific sera and gave 50% inhibition of the binding of extracts at about 0.1 µg/ml.
Allergen properties & biological function:Tropomyosins bind to actin in muscle increasing thin filament stability and rigidity. Depolymerization from the pointed end is inhibited, without affecting elongation (Broschat, 1990 [1589]). As tropomyosin prevents the binding of myosin, it may play an important role with troponin in controlling muscle contraction. The sequence exhibits a prominent seven-residues periodicity and this is reflected in the interactions of the 2 polypeptide chains which form a coiled coil structure of two alpha-helices as originally proposed by Crick in 1952 (see the porcine structure 1C1G). Some tropomyosins are N-acetylated modifying the structure of the N terminal region and increasing the affinity for the thin filaments (Greenfield & Fowler, 2002 [1590]).
Allergen purification:
Leung et al (1998) [1555] report the production of recombinant Hom a 1 (also rPan s 1 and rMet e 1) as 60 kDa GST-fusion proteins using the pGEX 1 expression system in E. coli. Only the purification of rPan s 1 is explicitly described starting with a 500 ml culture. Cells were suspended in 5 mls of lysis buffer (1% Triton X-100, 1% Tween-20, 10 mM DTT) and sonicated. The cell debris was demoved by centrifugation at 6000 x g for 15 minutes and the supernatant was added to glutathione agarose (Sigma, St. Louis, MO). After incubation for 2 hours on a rocker, the glutathione agarose was washed 3 times with PBS, pH 7.3, containing 1% Triton X-100 and the bound protein eluted in 2 mls of 5 mM reduced glutathione in 50 mM Tris/HCL, pH 8.0.
Native tropomyosin was prepared from Homarus americanus extract was SDS-PAGE as described in immunoblotting.
Other biochemical information:There is also a sequence deposited of slow-tonic S2 tropomyosin http://us.expasy.org/uniprot/Q6E7L4 with 279/284 (98%) identity.

References (7)

Leung PS, Chen YC, Mykles DL, Chow WK, Li CP, Chu KH.
Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen.
Mol Mar Biol Biotechnol. 7(1):12-20.. 1998
PUBMEDID: 9597774
Leung PS, Chen YC, Gershwin ME, Wong SH, Kwan HS, Chu KH.
Identification and molecular characterization of Charybdis feriatus tropomyosin, the major crab allergen.
J Allergy Clin Immunol. 102(5):847-852. . 1998
PUBMEDID: 9819304
DeWitt AM, Mattsson L, Lauer I, Reese G, Lidholm J.
Recombinant tropomyosin from Penaeus aztecus (rPen a 1) for measurement of specific immunoglobulin E antibodies relevant in food allergy to crustaceans and other invertebrates.
Mol Nutr Food Res. 48(5):370-379.. 2004
PUBMEDID: 15672477
Broschat KO.
Tropomyosin prevents depolymerization of actin filaments from the pointed end.
J Biol Chem. 265(34):21323-21329.. 1990
PUBMEDID: 2250026
Greenfield NJ, Fowler VM.
Tropomyosin requires an intact N-terminal coiled coil to interact with tropomodulin.
Biophys J. 82(5):2580-2591.. 2002
PUBMEDID: 11964245
Musmand JJ, Daul CB, Lehrer SB.
Crustacea allergy.
Clin Exp Allergy. 23(9):722-32.. 1993
PUBMEDID: 10779302
Leung PS, Chow WK, Duffey S, Kwan HS, Gershwin ME, Chu KH.
IgE reactivity against a cross-reactive allergen in crustacea and mollusca: evidence for tropomyosin as the common allergen.
J Allergy Clin Immunol. 98(5 Pt 1):954-961.. 1996
PUBMEDID: 8939159

Biochemical Information for Pan s 1

Allergen Name:Pan s 1
Alternatve Allergen Names:Tropomyosin
Allergen Designation:Major
Protein Family:Pfam PF00261; Tropomyosin family
Sequence Known?:Yes
Allergen accession No.s:http://us.expasy.org/cgi-bin/niceprot.pl?O61379
3D Structure Accession No.:N/A
Calculated Masses:31739 Da
Experimental Masses:
34 kDa
Oligomeric Masses:
Tropomyosins form dimers.
Allergen epitopes:Not known for Pan s 1. However, the data on shrimp allergens Pen a 1 and Pen i 1 are likely to be relevant because of cross-reactivity.
Allergen stability:
Process, chemical, enzymatic:The allergenicity of crustacea can survive cooking, possibly because tropomyosin have a very simple helical structure which can rapidly refold after denaturation. Extracts from boiled crustacea are frequently used in allergen purification and for extract preparation.
Nature of main cross-reacting proteins:
Leung et al (1998) [1555] reported the cloning of tropomyosins from Homarus americanus, Hom a 1, and Panulirus stimpsoni, Pan s 1. The sequence from Panulirus stimpsoni has 271/274 (98%) residues identical to the splice isoform O44119-2 from Homarus americanus. Leung et al (1998) [1555] reported that binding of IgE from sera from 10/10 crustacean allergic subjects to lobster extracts was inhibited by rMet e 1, rPan s 1 or rHom a 1.
Leung et al (1998) [1554] reported the percentage of amino acid identity of crab Cha f 1 with Met e 1, lobster Pan s 1 and Hom a 1 and Homarus americanus slow muscle, fruit fly and chicken tropomyosins as 90%, 91%, 92%, 96%, 69% and 60% respectively. They found that IgE from the sera from 10/10 crab allergic subjects bound rMet e 1, rPan s 1 and rHom a 1.
Allergen properties & biological function:Tropomyosins bind to actin in muscle increasing thin filament stability and rigidity. Depolymerization from the pointed end is inhibited, without affecting elongation (Broschat, 1990 [1589]). As tropomyosin prevents the binding of myosin, it may play an important role with troponin in controlling muscle contraction. The sequence exhibits a prominent seven-residues periodicity and this is reflected in the interactions of the 2 polypeptide chains which form a coiled coil structure of two alpha-helices as originally proposed by Crick in 1952 (see the porcine structure 1C1G). Some tropomyosins are N-acetylated modifying the structure of the N terminal region and increasing the affinity for the thin filaments (Greenfield & Fowler, 2002 [1590]).
Allergen purification:
Leung et al (1998) [1555] report the production of recombinant Pan s 1 (also rHom a 1 and rMet e 1) as 60 kDa GST-fusion proteins using the pGEX 1 expression system in E. coli. Only the purification of rPan s 1 is explicitly described starting with a 500 ml culture. Cells were suspended in 5 mls of lysis buffer (1% Triton X-100, 1% Tween-20, 10 mM DTT) and sonicated. The cell debris was demoved by centrifugation at 6000 x g for 15 minutes and the supernatant was added to glutathione agarose (Sigma, St. Louis, MO). After incubation for 2 hours on a rocker, the glutathione agarose was washed 3 times with PBS, pH 7.3, containing 1% Triton X-100 and the bound protein eluted in 2 mls of 5 mM reduced glutathione in 50 mM Tris/HCL, pH 8.0.
Other biochemical information:

References (4)

Leung PS, Chen YC, Mykles DL, Chow WK, Li CP, Chu KH.
Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen.
Mol Mar Biol Biotechnol. 7(1):12-20.. 1998
PUBMEDID: 9597774
Leung PS, Chen YC, Gershwin ME, Wong SH, Kwan HS, Chu KH.
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