Targeting CUB domain-containing protein 1 with a monoclonal antibody inhibits metastasis in a prostate cancer model.

Through a whole-cell panning approach, we previously identified a panel of antibodies that bound to prostate cancer cell surface antigens. One such antigen, CUB domain-containing protein 1 (CDCP1), was recognized by monoclonal antibody 25A11 and is a single transmembrane molecule highly expressed in several metastatic cancers as well as on CD34(+)CD133(+) myeloid leukemic blast cells. We show CDCP1 expression on prostate cancer cell lines by real-time quantitative PCR (RT-qPCR), flow cytometry, and immunohistochemistry and on prostate cancer patient samples by RT-qPCR and immunohistochemical staining.

A human antibody against anthrax protective antigen protects rabbits from lethal infection with aerosolized spores.

ALXN4100, a fully human antibody that binds to the protective antigen of anthrax toxin, was generated from a Fab isolated from a phage display library and was analyzed for its pharmacokinetic properties in rabbits and then used to protect rabbits from challenge with a lethal aerosol dose of Bacillus anthracis spores (approximately 322X LD(50)). All rabbits receiving 15 or 40 mg/kg of antibody 24 hours before challenge survived; survival of rabbits receiving 4 mg/kg either subcutaneously or intravenously was 80 or 90%, respectively. Susceptibility to anthrax disease appeared to be correlated with serum antibody concentration.

CD200 expression on tumor cells suppresses antitumor immunity: new approaches to cancer immunotherapy.

Although the immune system is capable of mounting a response against many cancers, that response is insufficient for tumor eradication in most patients due to factors in the tumor microenvironment that defeat tumor immunity. We previously identified the immune-suppressive molecule CD200 as up-regulated on primary B cell chronic lymphocytic leukemia (B-CLL) cells and demonstrated negative immune regulation by B-CLL and other tumor cells overexpressing CD200 in vitro. In this study we developed a novel animal model that incorporates human immune cells and human tumor cells to address the effects of CD200 overexpression on tumor cells in vivo and to assess the effect of targeting Abs in the presence of human immune cells.

Human antibodies from immunized donors are protective against anthrax toxin in vivo.

A panel of Fabs that neutralize anthrax toxin in vitro was selected from libraries generated from human donors vaccinated against anthrax. At least two of these antibodies protect rats from anthrax intoxication in vivo. Fabs 83K7C and 63L1D bind with subnanomolar affinity to protective antigen (PA) 63, and Fab 63L1D neutralizes toxin substoichiometrically, inhibits lethal factor (LF) interaction with PA63 and binds to a conformational epitope formed by PA63.