The invention provides a
tumor targeting fusion protein at least comprising (i) an IL-15 polypeptide, an IL-15 polypeptide variant, or a functional fragment thereof, (ii) an IL-15Ra polypeptide, an IL-15Ra polypeptide variant, or a functional fragment thereof, (iii) an Fc structural domain, an Fc variant, or a functional fragment thereof, and (iv) an RGD polypeptide or a variant thereof. The arraying sequence of the components of the
fusion protein is preferably the RGD polypeptide-the Fc structural domain-the IL-15 polypeptide-the IL-15Ra polypeptide. On one hand, the
tumor targeting fusion protein can enhance the anti-tumor
efficacy of the IL-15, and on the other hand, the
tumor targeting fusion
protein overcomes the problem of short half-life of the IL-15, also can target to a
tumor site, and targetedly acts on
tumor cells. In addition, the tumor targeting
protein can be efficiently expressed and purified, also has efficient
antitumor activity, and has the potential to become an anti-tumor therapeutic
drug.