Abstract
Humanized mice were generated in order to investigate the anti-tumor efficacy of bispecific antibodies. The engraftment, distribution and differentiation of mononuclear cells (MNC) from cord blood transplanted into the liver of newborn non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice were measured. Using a human-specific polymerase chain reaction (PCR), human cells were found to be present in the liver for a time range from 5 min to 5 days. After long-term engraftment of 42 days, the highest level of human cells was measured in mouse thymus, with lower levels in spleen and bone marrow. Engrafted human cells in mouse organs showed T-cell differentiation only, as measured by CD3, CD4 and CD8 expression. The MNC transplanted intrahepatically into newborn mice were tested for T-cell mediated anti-tumor activity in vivo against subcutaneously transplanted human SW480 colon carcinoma in NOD/SCID mice. A delay of SW480 tumor growth in mice in the presence of a bispecific epithelial cell-adhesion molecule (EpCAM)/CD3 antibody was found to be associated with the presence of immunoreactive human CD3 cells within the SW480 tumor. Our data provide evidence that the intrahepatic transplantation of cord blood stem cells into newborn mice represents a valuable model for establishing functionally active human T cells with anti-tumor activity.
Acknowledgments
The skilful technical assistance of Mrs Monika Becker is gratefully acknowledged. We thank the HELIOS-Clinics GmbH in Berlin-Buch and the Vivantes Clinics in Berlin for collecting and providing the umbilical CB. The bispecific antibody EpCAM/CD3 was kindly provided by P. Baeuerle (Micromet AG, Munich, Germany).
The work was partially supported by a grant from the Federal Ministry of Education and Research (BMBF; 01GN0528).
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.