Anti-IL13 monoclonal antibody [FITC]

We describe the expression and in vivo characterization of an antibody-cytokine fusion protein, based on murine Interleukin-13 (IL13) and the monoclonal antibody F8, specific to the alternatively spliced extra domain A of fibronectin, a marker of neo-angiogenesis. The IL13 moiety was fused at the C-terminal extremity of the F8 antibody in diabody format. The resulting F8-IL13 immunocytokine retained the full binding properties of the parental antibody and cytokine bioactivity. The fusion protein could be expressed in mammalian cells, purified to homogeneity and showed a preferential accumulation at the tumor site. When used as single agent at doses of 200 mu g, F8-IL13 exhibited a strong inhibition of tumor growth rate in two models of cancer (F9 teratocarcinoma and Wehi-164), promoting an infiltration of various types of leukocytes into the neoplastic mass. This anticancer activity could be potentiated by combination with an immunocytokine based on the F8 antibody and murine IL12, leading to complete and long-lasting tumor eradications. Mice cured from Wehi-164 sarcomas acquired a durable protective antitumor immunity, and selective depletion of immune cells revealed that the antitumor activity was mainly mediated by cluster of differentiation 4-positive T cells. This study indicates that IL13 can be efficiently delivered to the tumor neo-vasculature and that it mediates a potent anticancer activity in the two models of cancer investigated in this study. The observed mechanism of action for F8-IL13 was surprising, since immunocytokines based on other payloads (e.g., IL2, IL4, IL12 and TNF) eradicate cancer by the combined contribution of natural killer cells and cluster of differentiation 8-positive T cells.

Capsular contracture remains the most frequent long-term complication after augmentation mammoplasty with silicone implants. Thereby, the main part of the fibrotic capsule is collagen. The collagenase of the bacterium Clostridium histolyticum is approved for the treatment of fibrotic diseases and has been demonstrated to be effective for capsular fibrosis treatment in the short term. However, long-term effectiveness is currently unknown but mandatory for clinical utilization. Forty-eight rats received miniature silicone implants and an injection with either collagenase (treatment group) or plain solvent solution (control group) 120 days post insertion. Ten and 60 days after the injections, the rats underwent 7-Tesla magnetic resonance imaging (MRI) and high-resolution ultrasound (HR-US). Capsule tissue was harvested, and capsule thickness and collagen density were evaluated through histology. Furthermore, the expression levels of inflammatory (CD68, IL4, IL10, IL12, IL13), pro-, and anti-fibrotic (TGFb1, TGFb3, Smad3, Col1-4) genes were analyzed using qRT-PCR. On days 10 and 60 after injection of collagenase, histology showed that capsule thickness was significantly reduced in the treatment group when compared with the control (p < 0.05). Thickness measurements were verified by MRI and HR-US analysis. Skin perforation occurred in two cases after collagenase injection. The initial up-regulation of pro-fibrotic and inflammatory genes 10 days after collagenase injection did not persist in the long term. Contrarily, on day 60, a slight trend towards lower expression levels with a significant down-regulation of TGFb3 was detected in the treatment group. The collagenase of the bacterium C. histolyticum effectively degrades capsular fibrosis around silicone implants with stable outcomes throughout 60 days post injection. Skin perforation and adequate and uniform drug distribution within the implant pocket are issues that need to be addressed. Further studies are warranted to clarify whether collagenase injections have the potential to become a viable treatment option for capsular contracture. This journal requires that authors 46 assign a level of evidence to each article. For a full 47 description of these Evidence-Based Medicine ratings, 48 please refer to the Table of Contents or the online 49 Instructions to Authors. www.springer.com/00266.