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Updated: May 3, 2026
Removal and Replacement of Endogenous Ligands from Lipid-Bound Proteins and Allergens
Published on: February 24, 2021
Bla g 3: a novel allergen of German cockroach identified using cockroach-specific avian single-chain variable
Taruna Khurana1, Maggie Collison1, Fook Tim Chew2
1Laboratory of Immunobiochemistry, Division of Bacterial, Parasitic, and Allergenic Products, US Food and Drug Administration, Bethesda, Maryland.
Background:
The IgE response to cockroach allergens is thought to be associated with asthma. German cockroach (GCr) allergen extract is a complex mixture of allergens, and the identification and characterization of immunodominant allergens is important for the effective diagnosis and treatment of GCr-induced asthma.
Objective:
To characterize a novel GCr allergen homologous to the American cockroach allergen Per a 3.
Methods:
GCr-specific avian monoclonal antibodies were used for direct immunoprecipitation of specific targets from whole-body GCr extract. Precipitated protein was identified by mass spectrometry and sequence analysis. Putative recombinant protein also was expressed, purified, and used for determination of allergenicity, determined by IgE enzyme-linked immunosorbent assay with serum from 61 GCr-allergic patients. The identified target also was analyzed for heat stability using a bead-based assay.
Results:
The immunoprecipitated target of monoclonal antibody 2A1 was identified as a novel allergen of GCr homologous to American cockroach allergen Per a 3. This homolog, designated Bla g 3, has an apparent mass of 78 kDa, can be measured in GCr extract using antibody 2A1, and is a heat-stable protein. Screening of 61 serum samples from GCr-allergic patients showed a 22% prevalence of Bla g 3-specific IgE.
Conclusion:
Bla g 3 is a GCr allergen with structural homology to American cockroach allergen Per a 3.
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