In vitro studies often do not reliably predict the behavior of cells in vivo. Therefore our goals are: (a) to study cellular players directly in situ by means of appropriate bioimaging technologies, (b) to quantify and model information obtained by bioimaging, (c) to develop approaches for comprehensive investigation of various cell types in defined microenvironments. In cancer, a number of immune and nonimmune cell types respond to tumor stimuli and exhibit complex regulatory or effector functions, for example through cell-cell contact and/or secretion of soluble factors. We use recent advances in in vivo imaging to yield new insights into the biology of host cells with the ultimate goal to quantify cellular responses in vivo. As detailed below, we have focused our efforts on the study of T cell responses (anti-tumor CTL and suppressor Treg cells) and monocyte responses (monocyte subsets with distinct inflammatory potential and their lineage descendants).

Mononuclear phagocytes exert crucial functions as scavengers and can trigger or regulate immune responses. Recent studies indicate that monocytes - the precursors of macrophages and dendritic cells - comprise separate subsets that 'commit' to specific functions. The activity of these subsets in vivo is largely unknown. We are studying tissue tropism, cellular differentiation and role in immunity of monocyte subsets in various inflammatory conditions. We are also testing whether these cells are potential targets in therapy.