Action of novel CD37 antibodies on chronic lymphocytic leukemia cells

What is it about?

The potential for treating chronic lymphocytic leukemia (CLL) with two newly developed mouse-human chimeric and humanized CD37 antibodies, mAb 37.1 and mAb 37.2, was assessed on CLL lymphocytes ex vivo, on which the relative surface expression of CD37 appeared consistently stronger than that of CD20. In freshly isolated CLL lymphocytes the mean direct cell death (DCD) induction upon treatment for 24 hours with 10 μg mAb 37.1 per ml was 51% or 28% when monitored as phosphatidylserine exposure without or with concomitant membrane disintegration, respectively, and greatly surpassed that by rituximab (12% or 9%). In order to explore antibody effects including Fc-mediated mechanisms, antibody-induced B-cell depletion from whole blood samples was investigated using the same antibody concentration and treatment time. The mean percentages of CLL cell depletion from whole blood samples by mAb 37.1, mAb 37.2 or rituximab were 31%, 19% or 10%, respectively. Therefore the efficient DCD induction by CD37 antibodies contributes substantially to the overall antibody-mediated elimination of tumor cells. In summary, both novel CD37 antibodies show significantly higher DCD induction and CLL cell depletion from whole blood than rituximab, with mAb 37.1 exhibiting stronger effects than mAb 37.2. (Abstract provided by author, since the publication does not contain an abstract.)

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