Recombinant Shrimp Allergen: Pen a 1 -- MEDICA - World Forum for Medicine

11/08/2018

DIARECT AG

Recombinant Shrimp Allergen: Pen a 1

Penaeus aztecus (brown shrimp), also known as Farfantepenaeus aztecus, is closely related to the most imported species of farmed crustaceans worldwide, the giant tiger prawn (P. monodon). Despite the fact that shrimp-based food is a significant source of cholesterol, it is considered healthy for the cardiovascular system, due to the low levels of saturated fat. The high cholesterol content in shrimp improves the ratio of LDL to HDL cholesterol and lowers triglycerides. Moreover, shrimp is high in calcium, iodine, protein and omega-3s. However, hypersensitivity to crustacean food is relatively common and clinical manifestations following ingestion can be severe, including local and systemic reactions, which can lead, in the most severe cases, to life-threatening anaphylaxis.

The use of recombinant proteins in allergy diagnostics has several advantages over crude allergen extracts including more precise quantification of the immunologically active substance. Extracts that are prepared from natural sources may contain mixtures of several proteins including non-allergens, and can vary from batch to batch. Recombinant allergens are therefore the ideal basis to improve component resolved diagnostics (CRD) since large quantities with high purity and standardized quality can be produced.

Although a large number of crustacean and mollusk species have been studied, only a few IgE-binding proteins have been identified. In the majority of these studies the identified allergen component is tropomyosin and its isoform variants in other invertebrates. The protein, considered to be the only major allergen in shrimp, is a highly conserved and soluble muscle protein characterized by an alpha-helical homodimeric, coiled-coil structure. It plays a functional role in contractile activities of cells and is therefore important in the regulation of cell morphology and motility. Immunological relationship due to IgE cross-reactivites among crustaceans and the high degree of homologous regions within this protein family suggest that tropomyosin is an important cross-sensitizing pan allergen.

Tropomyosin of P. aztecus (34 - 38 kDa), designated Pen a 1, is representative of shrimp tropomyosin, used in the investigation of food allergies in which tropomyosin is a major determinant. From the thirteen different allergens identified in brown shrimp, it is the best characterized, been detected in sera of more than 80% of shrimp allergic subjects, and binds to 75% of the shrimp-specific IgE.

DIARECT’s recombinant Pen a 1 has close biochemical and immunological similarity to purified natural tropomyosin and is produced in the baculovirus/insect cell expression system.

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