Aedes aegypti Salivary Gland Extract as Important Novel Therapeutic Option for Experimental Colitis

Current therapies for inflammatory bowel disease (IBD) are not totally effective, resulting in continued disease burden for many patients.  Mosquito saliva contains immunomodulatory molecules and therein could represent a novel therapy for IBD. To investigate the impact of Aedes aegypti salivary gland extract (SGE) on an experimental model of IBD, C57BL/6 male mice were exposed to 3% DSS in drinking water for 6 days and concurrently treated with SGE or PBS. On the 6^th day, spleens and mesenteric lymph nodes (MLN) were harvested. Cytokine production and leukocytes profiles were assessed using flow cytometry. SGE treatment resulted in improved clinical disease outcome and postmortem scores. Within both the spleen and MLN, frequency of CD3^-CD49b⁺ cells was reduced. In the MLN, frequency of CD4⁺CD25⁺ cells was increased. Cultured CD4⁺ cells from spleen and MLN of SGE-treated mice produced lower levels of IFN-γ, IL17, and IL4, when compared to CD4⁺ cells from PBS-treated mice (Fig. 3). These results indicate that SGE could be a source of immunomodulatory molecules with promising therapeutic activity for IBD.