Allergenicity of recombinant Bla g 7, German cockroach tropomyosin.
BACKGROUND
Cockroach infestation may sensitize and elicit allergic responses to genetically predisposed individuals. Invertebrate tropomyosins are a frequent cause of allergy and highly cross-reactive in nature. In this study, we aimed to produce recombinant German cockroach tropomyosin and investigate its allergenicity.


METHODS
German cockroach tropomyosin (Bla g 7) was cloned by reverse transcriptase polymerase chain reaction (RT-PCR). The cloned cDNA was over-expressed in Escherichia coli and purified by affinity chromatography using Ni-nitrilotriacetic (NTA) acid resin. The allergenicity of the recombinant tropomyosin was examined by enzyme-linked immunosorbent assay (ELISA).


RESULTS
The cloned Bla g 7 shared up to 91% amino acid sequence identity with other cockroach tropomyosins. ELISA showed a recombinant Bla g 7 sensitization rate of 16.2% to German cockroach allergic sera. Recombinant tropomyosin was able to inhibit 32.4% of the specific IgE binding to cockroach extract.


CONCLUSIONS
Tropomyosin represents a minor allergen in cockroach extracts. It is hoped that recombinant tropomyosin will be useful for further studies and clinical applications.
D000485:Allergens / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D052179:Antigens, Plant; D001483:Base Sequence; D020048:Blattellidae / Q000276:immunology*; D003001:Cloning, Molecular; D015870:Gene Expression; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000276:immunology; D016415:Sequence Alignment; D014335:Tropomyosin / Q000235:genetics / Q000276:immunology*
D000485:Allergens; D052179:Antigens, Plant; C481502:Bla g 7 allergen, Blattella germanica; D011994:Recombinant Proteins; D014335:Tropomyosin; D007073:Immunoglobulin E