Partial characterization of mosquito larvae extract modulating mouse and human cell proliferation

Mosquito larvae crude extract have been found to alter the mitotic rate of several mouse epithelial cell populations such as enterocytes and tongue keratinocytes. Also, the dialysed fraction inhibits hepatocyte proliferation in hepatectomized males. These experiments suggested an inhibitory effect on the G1/S interphase. Consequently, we suggested the presence of some molecule or molecules related to the TGF-beta superfamily. In the present paper, we have assayed the crude extract on human mononuclear cells and the dialysed fraction of the extract on tongue keratinocyte proliferation. Furthermore, different protein fractions obtained using a molecular exclusion chromatographic column were assayed on hepatocyte proliferation of hepatectomized mice. Three groups of proteins have been isolated. Results show a dose-dependent effect of crude extract on mononuclear cell proliferation and the dialysed extract caused an inhibitory effect on tongue keratinocyte proliferation. With regard to the hepatocyte mitotic rate, an inhibitory effect appeared only in animals receiving the fraction with lower molecular weight. These results suggest the presence in mosquito larvae of some peptidic molecule or molecules resembling the activity of members of the TGF-beta superfamily.