Serial killing of tumor cells by cytotoxic T cells redirected with a CD19-/CD3-bispecific single-chain antibody construct

Item Type:	Article
Title:	Serial killing of tumor cells by cytotoxic T cells redirected with a CD19-/CD3-bispecific single-chain antibody construct
Creators Name:	Hoffmann, P. and Hofmeister, R. and Brischwein, K. and Brandl, C. and Crommer, S. and Bargou, R. and Itin, C. and Prang, N. and Baeuerle, P.A.
Abstract:	Certain bispecific antibodies exhibit an extraordinary potency and efficacy for target cell lysis by eliciting a polyclonal T-cell response. One example is a CD19-/CD3-bispecific single-chain antibody construct (bscCD19xCD3), which at femtomolar concentrations can redirect cytotoxic T cells to eliminate human B lymphocytes, B lymphoma cell lines and patient-derived malignant B cells. Here we have further explored the basis for this high potency. Using video-assisted microscopy, bscCD19xCD3 was found to alter the motility and activity of T cells from a scanning to a killing mode. Individual T cells could eliminate multiple target cells within a 9 hr time period, resulting in nuclear fragmentation and membrane blebbing of target cells. Complete target cell elimination was observed within 24 hr at effector-to-target cell ratios as low as 1:5. Under optimal conditions, cell killing started within minutes after addition of bscCD19xCD3, suggesting that the rate of serial killing was mostly determined by T-cell movement and target cell scanning and lysis. At all times, T cells remained highly motile, and no clusters of T and target cells were induced by the bispecific antibody. Bystanding target-negative cells were not detectably affected. Repeated target cell lysis by bscCD19xCD3-activated T cells increased the proportion of CD19/CD3 double-positive T cells, which was most likely a consequence of transfer of CD19 from B to T cells during cytolytic synapse formation. To our knowledge, this is the first study showing that a bispecific antibody can sustain multiple rounds of target cell lysis by T cells.
Keywords:	Cytotoxicity, Bispecific antibody, CD19, CD3
Source:	International Journal of Cancer
ISSN:	0020-7136
Publisher:	Wiley
Volume:	115
Page Range:	98-104
Date:	1 January 2005
Official Publication:	https://doi.org/10.1002/ijc.20908
PubMed:	View item in PubMed

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