Abstract: The present invention relates to immune-stimulating IL-2 fusion proteins comprising antibodies joined to human interleukin-2 (hIL-2). The invention more specifically relates to humanized monoclonal antibodies or fragments thereof joined to hIL-2 or variants thereof and displaying a unique capability of preferentially stimulating cytotoxic T cells and NK cells compared to Treg cells. Furthermore, the invention relates to in vitro and in vivo therapeutic applications of the IL-2 fusion proteins, in particular as an immunotherapy in the treatment of cancer.