マウス顎下腺抽出液のリンパ球幼若化反応に対する抑制作用

Abstract

The present study was conducted to identify the presence of the suppressive factor(s) in the submandibular gland of male mouse to the blastogenesis of mitogen-stimulated lymphocytes, and the possible role of testosterone in the induction of this factor. Extract of the mandibular gland (MSG-extract) of male mouse inhibited directly concanavalin A- or lipopolysaccharide-induced blastogenesis of splenic lymphocytes. Furthermore, macrophages which had been stimulated with MSG-extract produced in its culture supernatant a suppressive effect on mitogen-induced lymphoblastogenesis. In contrast, MSG-extract of female mice did not affect the blastogenesis of mitogen-stimulated splenocytes. However, MSG-extract of female mice treated with testosterone exhibited a similar suppressive effect, although testosterone did not exert such effect on lymphocytes at the same concentrations as detectable in MSG-extract of male mice. The suppressive activity of MSG-extract of male submandibular gland was heat-stable and with isoelectric focusing analysis, the isoelectric point of this factor was determined to be 7. 4. Thus, the present study has shown that in male submandibular glands there in an immunosuppressive factor as well as immunoenhancing factors including several growth factors, and the production of this factor by the submandibular gland was regulated by testosterone. These results may suggest that the difference in immune responses between males and females in partly attributable to that in the biological activity of submandibular glands between the two sexes.