title: Differential modulation of murine cellular immune responses by salivary gland extract of Aedes aegypti.
abstract: The ability of salivary gland extract (SGE) of Aedes aegypti to modulate cellular immune responses was investigated in a mouse model. Cytokine production was induced in naive and antigen-primed murine (BALB/c) spleen cells in vitro by stimulation with the T cell mitogen concanavalin A or the T cell-dependent antigen ovalbumin (OVA), respectively. Inclusion of Ae. aegypti SGE in in vitro culture with naive cells caused significant suppression of the cytokines interleukin-2 (IL-2) and interferon gamma in culture supernatants, while levels of other cytokines (IL-4 and IL-5) were unaffected by SGE. In contrast, SGE did not affect cytokine production by antigen-activated cells derived from OVA-primed mice. To determine whether SGE could inhibit the responsiveness of cells to exogenous cytokine stimuli, optimized quantities of lymphocyte growth factor cytokines IL-2 and IL-4 were added to SGE-treated spleen cells and the degree of cellular proliferation was determined. Cellular proliferation in response to IL-2 was markedly suppressed by prior exposure of cells to SGE, while the proliferative response to IL-4 was also affected by SGE but to a lesser extent. These results confirm that mosquito SGE can modulate host immune responses, and suggest that in Ae. aegypti modulation is directed primarily against cytokines associated with type 1 lymphocyte responses. The mode of immunomodulation and the possible relevance of these results to vector-borne disease research are discussed.
authors.affiliation: Department of Veterinary Science, University of Arizona, Tucson.
authors.forename: M L
authors.initials: ML
authors.lastname: Cross
authors.forename: E W
authors.initials: EW
authors.lastname: Cupp
authors.forename: F J
authors.initials: FJ
authors.lastname: Enriquez
mesh_terms: D000330:Aedes / Q000276:immunology*; D000818:Animals; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D005260:Female; D007111:Immunity, Cellular; D007303:Insect Vectors / Q000276:immunology*; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D012469:Salivary Glands / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D016207:Cytokines; D007376:Interleukin-2; D011994:Recombinant Proteins; D003208:Concanavalin A; D015847:Interleukin-4; D010047:Ovalbumin