Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease without effective therapeutics. Periostin has been reported to be elevated in IPF patients relative to controls, but its sources and mechanisms of action remain unclear. We confirm excess periostin in lungs of IPF patients and show that IPF fibroblasts produce periostin. Blood was obtained from 54 IPF patients (all but 1 with 48 wk of follow-up). We show that periostin levels predict clinical progression at 48 wk (hazard ratio = 1.47, 95% confidence interval = 1.03–2.10, P < 0.05). Monocytes and fibrocytes are sources of periostin in circulation in IPF patients. Previous studies suggest that periostin may regulate the inflammatory phase of bleomycin-induced lung injury, but periostin effects during the fibroproliferative phase of the disease are unknown. Wild-type and periostin-deficient (periostin^−/−) mice were anesthetized and challenged with bleomycin. Wild-type mice were injected with bleomycin and then treated with OC-20 Ab (which blocks periostin and integrin interactions) or control Ab during the fibroproliferative phase of disease, and fibrosis and survival were assessed. Periostin expression was upregulated quickly after treatment with bleomycin and remained elevated. Periostin^−/−mice were protected from bleomycin-induced fibrosis. Instillation of OC-20 during the fibroproliferative phase improved survival and limited collagen deposition. Chimeric mouse studies suggest that hematopoietic and structural sources of periostin contribute to lung fibrogenesis. Periostin was upregulated by transforming growth factor-β in lung mesenchymal cells, and periostin promoted extracellular matrix deposition, mesenchymal cell proliferation, and wound closure. Thus periostin plays a vital role in late stages of pulmonary fibrosis and is a potential biomarker for disease progression and a target for therapeutic intervention.

We sought to enhance the selective toxicity of tumor necrosis factor α (TNFα) to permit its systemic use in cancer therapy. Because ligand-targeted therapeutics have proven successful in improving the selective toxicity of drugs, we prepared a fusion protein (L19mTNFα) composed of mouse TNFα and a high-affinity antibody fragment (L19 scFv) to the extradomain B (ED-B) domain of fibronectin, a marker of angiogenesis. L19mTNFα was expressed in mammalian cells, purified, and characterized. L19mTNFα was an immunoreactive and biologically active homotrimer. Radiolabeled L19mTNFα selectively targeted tumor neovasculature in tumor-bearing mice, where it accumulated selectively and persistently (tumor-to-blood ratio of the percentage of injected dose per gram [%ID/g] of 700, 48 hours from injection). L19mTNFα showed a greater anticancer therapeutic activity than both mTNFα and TN11mTNFα, a control fusion protein in which an antibody fragment, irrelevant in the tumor model used, substituted for L19. This activity was further dramatically enhanced by its combination with melphalan or the recently reported fusion protein L19-IL2. In conclusion, L19mTNFα allows concentrating therapeutically active doses of TNFα at the tumor level, thus opening new possibilities for the systemic use of TNFα in cancer therapy. (Blood. 2003;102:4384-4392)

Antibody-cytokine fusion proteins (immunocytokine) exert a potent anti-cancer effect; indeed, they target the immunosuppressive tumor microenvironment (TME) due to a specific anti-tumor antibody linked to immune activating cytokines. Once bound to the target tumor, the interleukin-2 (IL-2) immunocytokines composed of either full antibody or single chain Fv conjugated to IL-2 can promote the in situ recruitment and activation of natural killer (NK) cells and cytotoxic CD8⁺ T lymphocytes (CTL). This recruitment induces a TME switch toward a classical T helper 1 (Th1) anti-tumor immune response, supported by the cross-talk between NK and dendritic cells (DC). Furthermore, some IL-2 immunocytokines have been largely shown to trigger tumor cell killing by antibody dependent cellular cytotoxicity (ADCC), through Fcγ receptors engagement. The modulation of the TME can be also achieved with immunocytokines conjugated with a mutated form of IL-2 that impairs regulatory T (Treg) cell proliferation and activity. Preclinical animal models and more recently phase I/II clinical trials have shown that IL-2 immunocytokines can avoid the severe toxicities of the systemic administration of high doses of soluble IL-2 maintaining the potent anti-tumor effect of this cytokine. Also, very promising results have been reported using IL-2 immunocytokines delivered in combination with other immunocytokines, chemo-, radio-, anti-angiogenic therapies, and blockade of immune checkpoints. Here, we summarize and discuss the most relevant reported studies with a focus on: (a) the effects of IL-2 immunocytokines on innate and adaptive anti-tumor immune cell responses as well as immunosuppressive Treg cells and (b) the approaches to circumvent IL-2-mediated severe toxic side effects.

Decidual natural killer cells accumulate at the fetal-maternal interface and play a key role in a successful pregnancy. However, their origin is still unknown. Do they derive from peripheral natural killer cells recruited in decidua or do they represent a distinct population that originates in situ ? Here, we identified natural killer precursors in decidua and uterus of pregnant mice. These precursors underwent rapid in situ differentiation and large proportions of proliferating immature natural killer cells were present in decidua and uterus as early as gestation day 4.5. Here, we investigated the origin of decidua- and uterus-natural killer cells by performing transfer experiments of peripheral mature natural killer cells or precursors from EGFP+ mice. Results showed that mature natural killer cells did not migrate into decidua and uterus, while precursors were recruited in these organs and differentiated towards natural killer cells. Moreover, decidua- and uterus-natural killer cells displayed unique phenotypic and functional features. They expressed high levels of the activating Ly49D receptor in spite of their immature phenotype. In addition, decidua- and uterus-natural killer cells were poorly cytolytic and produced low amounts of IFN-γ, while they released factors (GM-CSF, VEGF, IP-10) involved in neo-angiogenesis and tissue remodeling. Our data reveal in situ generation of decidual natural killer cells and provide an important correlation between mouse and human decidual natural killer cells, allowing further studies to be carried out on their role in pregnancy-related diseases.