Expression and release of stable and active forms of murine granulocyte-macrphage colony-stimulating factor (mGM-CSF) targeted to different subcellular compartments

Cytokines have been used for several years as immunomodulators, However, on e of the main drawbacks of systemically applied cytokines is their high tox icity. In addition, cytokines work in a paracrine form and frequently after cell-to-cell interaction. Therefore, a very restricted release of cytokine s - in time and space - could be desired for most of their therapeutic appl ications, The murine granulocyte-macrophage colony-stimulating factor (mGM- CSF) is one of the most promising cytokine candidates for cancer immunother apy and as an adjuvant of DNA vaccines. With the aim of improving the admin istration and release of cytokines in a very restricted area, we have desig ned vectors expressing the mGM-CSF cDNA with different localization signals . Using this strategy we have shown that cytokines can be expressed and tar geted to different subcellular compartments (i.e. the cytoplasm, the endopl asmic reticulum and the nucleus), stored inside the cells and released afte r cell lysis as stable active proteins. Moreover, a plasma membrane targete d form of mGM-CSF displayed substantial amount of biological activity, Thes e vectors could have potential applications in immunotherapy for tumours an d DNA vaccination protocols. (C) 2001 Academic Press.