Henrikki Brummer-Korvenkontio

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.

Allergens in latex surgical gloves and glove powder

treatment. Lp(a) concentrations were assessed with the ’TintElize’ Lp(a) enzyme immunoassay (Biopool, Umea, Sweden). The median pretreatment Lp(a) concentration was 16-6 mg/dl (range 1-112-8) in patients in whom recanalisation occurred (TIMI grade 2 or 3) at 90 minutes after initiation of thrombolytic therapy and was 15-5 mg/dl (range 0-142-2) in patients in whom it did not. The proportions of patients with pretreatment Lp(a) values of 20 mg/dl

Seasonal increase in human IgE and IgG4 antisaliva antibodies to Aedes mosquito bites.

BACKGROUNDnMosquito bite-sensitive subjects frequently have circulating IgE and IgG4 antibodies to Aedes mosquito saliva proteins.nnnMETHODSnIn the present study we examined the antibody response during a mosquito season in 14 subjects living in Finnish Lapland. Immunoblotting was performed with Aedes communis saliva and the 22- and 36-kD antisaliva antibody bands were analyzed.nnnRESULTSnThe preseason sera showed IgE antibodies to the main saliva antigens in 12, IgG4 antibodies in all 14 and IgG1 antibodies in 12 subjects, and the postseason sera in all but 1 subject. The postseason sera showed significantly more intense IgE (p < 0.05), IgG4 (p < 0.001) and IgG1 (p < 0.01) antibody bands than the preseason sera.nnnCONCLUSIONnThese results show that seasonal exposure to mosquito bites leads to an increased IgE, IgG4 and IgG1 antibody response, a phenomenon similar to that occurring e.g. in pollen allergy.

Are We Really Allergic to Mosquito Bites

Most, if not all, people are sensitized to mosquito bites in childhood. Cutaneous symptoms include immediate wheal-and-flare reactions and delayed bite papules, which tend to be more severe at the onset of the mosquito season. Systemic reactions to mosquito bites are, however, very rare. Recent immunoblot studies have demonstrated IgE antibodies to Aedes communis mosquito saliva 22 and 36 kD proteins. This confirms that specific sensitization occurs in man and indicates that mosquito-bite whealing is a classic type I allergic reaction. The delayed mosquito-bite papules seem to be cutaneous late-phase reactions mediated by eosinophils or they could also represent type IV lymphocyte-mediated immune reactions. People living in heavily infested areas such as Lapland frequently acquire tolerance to mosquito bites, and seem to have negligible levels of IgE but high amounts of IgG4 antisaliva antibodies. Desensitization treatment is a theoretical possibility but prophylactically given cetirizine, an H1-blocking antihistamine, has been shown to be helpful for people suffering from mosquito bites.

Characterization of Aedes communis, Aedes aegypti and Anopheles stephensi mosquito saliva antigens by immunoblotting

BACKGROUNDnMosquito bites cause immediate wheals and delayed bite papules in sensitized subjects having saliva-specific IgE and IgG4 antibodies. At present, mosquito saliva antigens are not well characterized.nnnMETHODSnTo identify immunogenic proteins in mosquito saliva and study their cross-reactivity we immunized mice with Aedes communis, Aedes aegypti and Anopheles stephensi bites. Immune sera were used in immunoblotting and immunoblot inhibition experiments.nnnRESULTSnThe main A. communis saliva antigens were 22-, 30-, and 36-kD, A. aegypti saliva antigens 31-, 36-, 46- and 64- to 66-kD, and A. stephensi saliva antigen 46-kD proteins. Most of the saliva antigens appeared to be species-specific and only weak cross-reactivity was observed with heterologous immune sera. Distinct cross-reactivity was observed only between saliva proteins of A. communis and Aedes punctor, two taxonomically closely related species. Human IgE and IgG4 antibodies from mosquito-bite-sensitive children bound to the same saliva proteins as antibodies from the immunized animals.nnnCONCLUSIONSnThis study disclosed several immunogenic proteins in Aedes and Anopheles mosquito saliva and suggests that these proteins can also be allergenic in man.

Passive transfer of cutaneous mosquito-bite hypersensitivity by IgE anti-saliva antibodies

BACKGROUNDnMosquito bites frequently cause cutaneous wheal and flare reactions, and recent immunoblotting studies have shown specific anti-saliva IgE antibodies in many persons who have such reactions.nnnOBJECTIVEnThe study was designed to show that human serum containing mosquito saliva-specific IgE antibodies can produce histamine release in vitro and whealing in vivo.nnnMETHODSnTwo mosquito bite-tolerant subjects had bite challenges and Prausnitz-Küstner tests with heated and unheated serum from one patient with Aedes mosquito allergy. Immunoblotting and basophil histamine release tests were performed with the patients and subjects sera.nnnRESULTSnBoth mosquito bite-tolerant subjects had positive Prausnitz-Küstner reactions, which indicated a successful transfer of cutaneous mosquito hypersensitivity. The ordinary and passive basophil histamine release tests also produced positive results with Aedes communis antigens.nnnCONCLUSIONnThe results of the Prausnitz-Küstner test, immunoblotting, and basophil histamine release tests are consistent with the hypothesis that mosquito bite whealing is mediated by specific anti-saliva IgE antibodies.

Histamine and leukotriene C4 release in cutaneous mosquito-bite reactions

BACKGROUNDnMosquito bites are known to sensitize persons, and the most common cutaneous reactions are immediate wheals and delayed bite papules. Anti-saliva IgE and IgG4 antibodies are common in mosquito-sensitive subjects, but mediator release in bite reactions is not known.nnnMETHODSnWe used the microdialysis technique to measure in vivo histamine and leukotriene C4 release after bite challenges in six mosquito-sensitive subjects. One individual who was not sensitive to bites volunteered as a control subject.nnnRESULTSnThree of the six mosquito-sensitive subjects had large wheals and showed clearly increased histamine concentrations 30 to 45 minutes after the bites. The histamine levels declined to baseline value within 2 hours; thereafter, one subject showed a second increase in histamine concentration. Four of the six mosquito-sensitive subjects showed increased leukotriene C4 concentrations, and this mediator seemed to be released somewhat later than histamine.nnnCONCLUSIONSnThe increased histamine and leukotriene C4 release observed in this study suggests that both mediators are involved in the early allergic response caused by mosquito bites.

Immunization of rabbits with mosquito bites: immunoblot analysis of IgG antimosquito antibodies in rabbit and man.

Rabbits immunized with 50-60 Aedes communis mosquito bites developed IgG antibodies recognizing a 21.5-kD mosquito antigen detected by the immunoblot technique. This protein seems to be a major immunogen in the saliva of A. communis mosquitoes. Studies on 60 human sera revealed that IgG antibodies recognizing the 21.5-kD antigen occurred in about 50% of young children and adults but were not found in the sera of 20 unexposed infants. The present immunoblot method allows further characterization of antigens and antibodies specific to mosquito saliva and contributes to understanding their role in mosquito bite reactions.