Comparison of proteins, IgE, and IgG binding antigens, and skin reactivity in commercial and laboratory-made mosquito extracts.

BACKGROUND

Commercial extracts are available for the diagnosis and treatment of mosquito allergy, but their antigen content has never been analyzed.

OBJECTIVE

We wanted to analyze commercially available mosquito extracts and to compare these extracts with different laboratory preparations.

METHODS

Seven commercially available mosquito whole body extracts from six companies and four laboratory mosquito preparations including saliva extract were studied. Epicutaneous tests and measurement of protein concentration were performed. Protein components were identified by sodium sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver stain. IgE and IgG binding antigens were analyzed by SDS-PAGE and immunoblotting with sera from mosquito-allergic subjects.

RESULTS

The seven commercial materials produced wheals and papules ranging from 0 to 36 mm2. Their protein concentrations varied from 0.1 to 4.9 mg/mL. There were significant differences in their protein and antigen components. Some extracts contained multiple highly immunoreactive proteins and IgE- and IgG-binding antigens that are not present in mosquito saliva, but few actual salivary antigens. In the four laboratory preparations, rank ordered from whole body, head and thorax, salivary gland to saliva extracts, the amount of salivary antigens significantly increased, while non-salivary proteins and antigens significantly decreased.

CONCLUSIONS

Commercial mosquito extracts should be standardized. Purer mosquito extracts should be used in diagnosis and immunotherapy of mosquito allergy.