Different tissue distribution properties for glycosylation variants of fusion proteins containing the p40 subunit of murine interleukin-12

Antibody-based delivery of interleukin-9 to neovascular structures: Therapeutic evaluation in cancer and arthritis

Interleukin-9 is a cytokine with multiple functions, including the ability to activate group 2 innate lymphoid cells, which has been postulated to be therapeutically active in mouse models of arthritis. Similarly, interleukin-9 has been suggested to play an important role in tumor immunity. Here, we describe the cloning, expression, and characterization of three fusion proteins based on murine interleukin-9 and the F8 antibody, specific to the alternatively spliced EDA domain of fibronectin. EDA is strongly expressed in cancer and in various arthritic conditions, while being undetectable in the majority of healthy organs. Interleukin-9-based fusion proteins with an irrelevant antibody specific to hen egg lysozyme served as negative control in our study. The fusion proteins were characterized by quantitative biodistribution analysis in tumor-bearing mice using radioiodinated protein preparations. The highest tumor uptake and best tumor:organ ratios were observed for a format, in which the interleukin-9 moiety was flanked by two units of the F8 antibody in single-chain Fv format. Biological activity of interleukin-9 was retained when the payload was fused to antibodies. However, the targeted delivery of interleukin-9 to the disease site resulted in a modest anti-tumor activity in three different murine models of cancer (K1735M2, CT26, and F9), while no therapeutic benefit was observed in a collagen induced model of arthritis. Collectively, these results confirm the possibility to deliver interleukin-9 to the site of disease but cast doubts about the alleged therapeutic activity of this cytokine in cancer and arthritis, which has been postulated in previous publications.

Homogeneously N-glycosylated proteins derived from the GlycoDelete HEK293 cell line enable diffraction-quality crystallogenesis

Structural studies of glycoproteins and their complexes provide critical insights into their roles in normal physiology and disease. Most glycoproteins contain N-linked glycosylation, a key post-translation modification that critically affects protein folding and stability and the binding kinetics underlying protein interactions. However, N-linked glycosylation is often an impediment to yielding homogeneous protein preparations for structure determination by X-ray crystallography or other methods. In particular, obtaining diffraction-quality crystals of such proteins and their complexes often requires modification of both the type of glycosylation patterns and their extent. Here, we demonstrate the benefits of producing target glycoproteins in the GlycoDelete human embryonic kidney 293 cell line that has been engineered to produce N-glycans as short glycan stumps comprising N-acetylglucosamine, galactose and sialic acid. Protein fragments of human Down syndrome cell-adhesion molecule and colony-stimulating factor 1 receptor were obtained from the GlycoDelete cell line for crystallization. The ensuing reduction in the extent and complexity of N-glycosylation in both protein molecules compared with alternative glycoengineering approaches enabled their productive deployment in structural studies by X-ray crystallography. Furthermore, a third successful implementation of the GlycoDelete technology focusing on murine IL-12B is shown to lead to N-glycosylation featuring an immature glycan in diffraction-quality crystals. It is proposed that the GlycoDelete cell line could serve as a valuable go-to option for the production of homogeneous glycoproteins and their complexes for structural studies by X-ray crystallography and cryo-electron microscopy.

Targeting an engineered cytokine with interleukin-2 and interleukin-15 activity to the neovasculature of solid tumors

There is a growing interest in the antibody-based delivery of cytokines to the tumor environment as a means to boost the anti-cancer activity of tumor-resident T cells and NK cells. Here, we describe the expression and characterization of fusion proteins, featuring the L19 antibody (specific to the alternatively-spliced EDB domain of fibronectin) and an engineered cytokine with interleukin-2 and interleukin-15 properties. The cytokine moiety was fused either at the N-terminal or at the C-terminal extremity and both fusion proteins showed a selective tumor accumulation in a quantitative biodistribution experiment. The N-terminal fusion inhibited tumor growth in immunocompetent mice bearing F9 carcinomas or WEHI-164 sarcomas when used as single agent. The anticancer activity was compared to the one of the same cytokine payload used as recombinant protein or fused to an anti-hen egg lysozyme antibody, serving as negative control of irrelevant specificity in the mouse. These results indicate that the antibody-based delivery of engineered cytokines to the tumor neovasculature may mediate a potent anticancer activity.