Macrophages
are specialised phagocytic cells that play a major role in the clearance of
infection or cellular debris in all living tissues. Here we describe the
development and implementation of a multi-parametric, primary-cell phenotypic
screen aimed at identifying compounds and/or molecular pathways that enhance
macrophage phagocytosis. Such compounds could provide novel therapeutic
starting points for diseases characterised by defective macrophage phagocytosis
and impaired bacterial clearance. The assay utilises high content imaging to
provide multiplexed information at the single cell level to quantify phagocytosis
using bacteria labelled with pHrodo^TM, a fluorogenic dye that
dramatically increases fluorescence in acidic environments such as the
phagosome.   In this talk we will discuss
the challenges and opportunities encountered through using a phenotypic-based
imaging approach, and highlight potential target deconvolution approaches that
may provide novel insights into compound mechanisms of action.