Role of tropomyosin in silkworm allergy.
Silkworm pupae are widely consumed in Asian countries and allergic reactions following consumption have been described. However, false‑positive responses in skin prick allergy tests or non‑specific immunoglobulin E (IgE) responses to total extract of silkworm pupa make diagnosis difficult. Although improved allergy diagnosis is required, molecular characterization of silkworm allergens has not been performed to date, except for Bomb m 1, an arginine kinase. This study aimed to evaluate the allergenicity of tropomyosin, a well‑established invertebrate pan‑allergen, from silkworm pupa. The silkworm tropomyosin gene was cloned by reverse transcription and polymerase chain reaction, and the protein was overexpressed in Escherichia coli and purified by affinity chromatography using Nickel‑resin. IgE reactivity of the recombinant protein was examined by ELISA and competitive inhibition analyses. Silkworm pupa tropomyosin shared 73.5‑92.3% amino acid sequence identity with previously identified allergenic tropomyosins. Sera from eight of 15 patients with silkworm allergy (53.3%) exhibited binding of IgE to the recombinant protein. However, recombinant protein was able to inhibit less than 10% of IgE reactivity to silkworm pupa extract. Of the eight sera tested, six that specifically reacted with silkworm tropomyosin also demonstrated IgE reactivity to shrimp and crab. In the present study, specific IgE to silkworm tropomyosin was detected in patients with silkworm allergy, suggesting that it may be useful in diagnosis of allergy to silkworm pupa.
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
Kyoung Yong
KY
Jeong
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
In-Soo
IS
Han
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
June Yong
JY
Lee
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
Kyung Hee
KH
Park
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
Jae-Hyun
JH
Lee
Department of Internal Medicine, Institute of Allergy, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
Jung-Won
JW
Park
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000937:Antigen-Antibody Reactions; D012831:Bombyx / Q000254:growth & development / Q000378:metabolism; D003386:Brachyura / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000473:pathology*; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D011679:Pupa / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D016415:Sequence Alignment; D012882:Skin Tests; D014335:Tropomyosin / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
D000485:Allergens; D011994:Recombinant Proteins; D014335:Tropomyosin; D007073:Immunoglobulin E