Murine monoclonal antibodies against murine uPA receptor produced in gene-deficient mice: Inhibitory effects on receptor-mediated uPA activity in vitro and in vivo

作者：Pass Jesper; Jogi Annika; Lund Ida K; Rono Birgitte; Rasch Morten G; Gardsvoll Henrik; Lund Leif R; Ploug Michael; Romer John; Dano Keld; Hoyer Hansen Gunilla^*

来源：Thrombosis and Haemostasis, 2007, 97(6): 1013-1022.

DOI：10.1160/TH06-11-0644

• plasminogen activation
• uPAR knock-out mice
• mouse antimouse mAbs
• inhibitors of uPA-uPAR interaction
• anthrax toxin assay

Binding of urokinase plasminogen activator (uPA) to its cellular receptor, uPAR, potentiates plasminogen activation and localizes it to the cell surface. Focal plasminogen activation is involved in both normal and pathological tissue remodeling processes including cancer invasion.The interaction between uPA and uPAR therefore represents a potential target for anti-invasive cancer therapy. Inhibitors of the human uPA-uPAR interaction have no effect in the murine system.To enable in-vivo studies in murine cancer models we have now generated murine monoclonal antibodies (mAbs) against murine uPAR (muPAR) by immunizing uPAR-deficient mice with recombinant muPAR and screened for antibodies, which inhibit the muPA-muPAR interaction. Two of the twelve mAbs obtained, mR1 and mR2, interfered with the interaction between muPAR and the amino-terminal fragment of muPA (mATF) when analyzed by surface plasmon resonance. The epitope for mRI is located on domain I of muPAR, while that of mR2 is on domains In cell binding experiments using radiolabelled mATF the maximal inhibition obtained with mRI was 85% while that obtained with mR2 was 50%. The IC50 value for mRI was 0.67 nM compared to 0.14 nM for mATF, In an assay based on modified anthrax toxins, requiring cell-bound muPA activity for its cytotoxity a similar to 50% rescue of the cells could be obtained by addition of mRI. Importantly, in-vivo efficacy of mRI was demonstrated by the ability of mRI to rescue mice treated with a lethal dose of uPA-activatable anthrax toxins.

• 出版日期2007-6