Detection of mosquito saliva-specific IgE and IgG4 antibodies by immunoblotting

IgE and IgG subclass antibodies against Aedes communis mosquito saliva were studied by immunoblotting in 12 adults with immediate and/or delayed skin reactions to mosquito bites. Four antigenic proteins, with molecular weights of 22, 30, 36, and 64 kd, were found in the mosquito saliva. Almost all subjects (11 of 12) had anti-mosquito saliva-specific IgE antibodies directed against the 36 kd protein. The IgG antibody response appeared to be restricted mostly to IgG4 (11 of 12) and IgG1 (8 of 11) subclasses against the same 36 kd antigen. Ten of the 12 subjects had both IgE and IgG4 antibodies to the 36 kd protein. No anti-mosquito antibodies were found in pooled sera of five infants never exposed to mosquito bites. These results show that most persons with immediate skin reactivity to A. communis mosquito bites have both IgE and IgG4 antibodies that recognize the 36 kd antigen present in the mosquito saliva, suggesting that anti-saliva antibodies may play a role in the pathogenesis of mosquito bite reactions.