apyrase and Insect-Bites-and-Stings

Human populations are constantly plagued by hematophagous insects' bites, in particular the triatomine insects that are vectors of the Trypanosoma cruzi agent in Chagas disease. The pharmacologically-active molecules present in the salivary glands of hematophagous insects are injected into the human skin to initiate acquisition of blood meals. Sets of vasodilators, anti-platelet aggregators, anti-coagulants, immunogenic polypeptides, anesthetics, odorants, antibiotics, and detoxifying molecules have been disclosed with the aid of proteomics and recombinant cDNA techniques. These molecules can provide insights about the insect-pathogen-host interactions essential for understanding the physiopathology of the insect bite. The data and information presented in this review aim for the development of new drugs to prevent insect bites and the insect-transmitted endemic of Chagas disease.

Topics: Animals; Apyrase; Chagas Disease; Hemostasis; Host-Pathogen Interactions; Humans; Insect Bites and Stings; Salivary Glands; Salivary Proteins and Peptides; Triatoma; Vasodilator Agents

Horsefly bite can cause allergic reactions in humans. There is no information about allergenic horsefly proteins.. The current work aims to purify and characterize IgE-binding proteins from horsefly salivary glands.. Two IgE-binding proteins, Tab a 1 and Tab a 2 with molecular weight of 26 and 35 kd, respectively, were purified and characterized from 60,000 pairs of horsefly salivary glands of Tabanus yao, respectively. Their primary sequences were determined by Edman degradation and cDNA cloning. Their allergenicity was examined using enzyme-linked immunosorbent assay (ELISA), ELISA inhibition tests, and immunoblots.. Immunoblotting demonstrated IgE binding by 32 and 34 of 37 (86.5% and 91.8%) subjects' sera to Tab a 1 and Tab a 2, respectively. They were identified as an antigen 5-related (Ag 5) protein and hyaluronidase, respectively. ELISA inhibitions of serum IgE reactivity to the horsefly salivary gland extract (SGE) using purified Tab a 1 and Tab a 2 were significant (about 45%). In addition, these proteins showed some IgE-binding capacity to sera of subjects with wasp sting allergy.. We have first identified and characterized two IgE-binding proteins, Tab a 1, an Ag 5-like protein and Tab a 2, a hyaluronidase, from the horsefly salivary glands. They appear to be of importance for the allergic reactions induced by horsefly bite. These allergens are thus not only found in stinging but also found in hematophagous insects. These results also provided support for the presence of the so-called wasp-horsefly syndrome (WHS).

Topics: Adolescent; Adult; Allergens; Amino Acid Sequence; Animals; Apyrase; Child; Diptera; Galectin 3; Gene Library; Humans; Hyaluronoglucosaminidase; Hypersensitivity, Immediate; Immunoblotting; Immunoglobulin E; Insect Bites and Stings; Middle Aged; Molecular Sequence Data; Salivary Glands; Young Adult

Mice (BALB/c) were immunized to mosquito saliva by repeated bites of Anopheles stephensi mosquitoes. Studies were conducted on the ability of these mice to develop antibodies against the apyrase component of the saliva. By means of immunoprecipitation procedures and Western blot analysis, we demonstrated the presence of antiapyrase antibodies to the mosquito saliva. Furthermore, these antibodies were able to inhibit apyrase activity. Serum titers of 1:20 were able to inhibit approximately 90% of salivary gland apyrase activity, while titers of 1:160 retained the ability to inhibit more than 50% of apyrase activity. Parallel inhibition assays with immunoglobulin G (IgG) from immunized versus nonimmunized mice showed that the inhibitory activity of serum from immunized mice could be accounted for by its IgG component. Mosquito salivary gland apyrase has previously been shown to facilitate mosquito feeding by inhibiting aggregation of platelets at the mosquito bite site. However, our studies have shown that mosquitoes feeding on immunized mice had no deficiency in probing these mice for a blood meal, even in the face of high titers of anti-apyrase antibodies.

Topics: Animals; Anopheles; Antibodies; Aorta; Apyrase; Blotting, Western; Cattle; Cell Line; Electrophoresis, Polyacrylamide Gel; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Insect Bites and Stings; Isoelectric Focusing; Mice; Mice, Inbred BALB C; Precipitin Tests; Salivary Glands