Objective
Charles
River Laboratories (CRL) are establishing a powerful translational immuno-oncology
platform with the capability of progressing biologics or small molecule
modulators of immune response from in vitro to in vivo assays using human and
mouse variants of current check-point inhibitors and small molecules.
The
platform is supported by an internal blood donor panel which ensures highly
reproducible data and high quality immune cells which are prepared immediately
once sampled.
Our in
vitro platform includes primary human immune cell assays which profile T cell
activation, cytokine release, T cell mediated cancer cell kill, expansion of T
cell populations, T cell invasion and macrophage mediated T cell phagocytosis.
The
platform is currently being expanded to determine the effect of activated
immune cell populations on tumour cell spheroid cultures. We are in the process
of developing a range of nuclear-restricted GFP expressing
cell lines which will be used to support co-culture experiments. The platform
has been validated with standard of care chemotherapeutics, including
anti-CTLA4, anti-PD1 and a selection of small molecule inhibitors of targets
known to modulate immune responses including IDO inhibitors.
Ex-vivo
analysis of activated mouse splenocytes response to check-point inhibitors
measured as cytokine release and modulation of immune cell populations, as
measured by flow cytometry supports the translation of important compounds from
the bench to pre-clinical models.
Syngeneic
mouse tumour models have frequently been used to profile immune responses in
tumours, CRL have optimized and profiled existing check-point inhibitors to
support immuno-oncology drug discovery using mouse and rat antibody variants of
anti-CTLA4 and anti-PD1.
To confirm
the translational development of our platform CRL have developed and optimized
humanized mouse models using sub-cutaneous implanted patient derived xenografts
(PDX) with human engraftment via CD34+ haematopoeitic stem cells in NOG mice
which were treated with anti-CTLA4 and anti-PD1. Infiltration of human immune
cells and PDL-1 expression was detected by flow cytometry (FC) and
immunohistochemistry (IHC) in hematopoietic organs and tumor tissue, supporting
the initial in vitro response in primary immune cells.
We present
a screening platform which will support translation of compounds from in vitro primary
immune cell assays, to modulation of mouse immune cell population in spleen and
tumours, resulting in efficacy and tumour immune cell activation in humanized
mouse models.
