*Purpose: The interplay between dendritic cells (DCs) and T cells plays a central role in the process of allograft rejection. Upon antigen exposure, positive costimulatory signals provided by DCs lead to T cell activation, while negative signals downmodulate the T cell response. The net balance of these signals ultimately determines allograft fate. In these experiments, our research is aimed at understanding of mechanisms of “the interplay”.

*Methods: We have now adapted the use of intravital microscopy (IVM) to track EYFP DC motility, morphology, and cell density in real-time ¹⁾.

*Results: Our preliminary data using cardiac transplant model showed that 1) dDC have already been activated during ischemic time (morphological changes), 2) both injected CD4⁺T cells and CD8⁺T cells (5millions on Day 0) were detected at graft, 3) and donor DC (EGFP) has already started cross-talking with CD4⁺T cells (red) right after reperfusion (Figure). 3-D pathological images also confirmed its finding.

*Conclusions: As we have reported the important roles of DCs in transplantation ²⁾, this proposal leads us to provide to investigate the role of donor dendritic cell-T cell interaction in graft rejection versus tolerance utilizing “state-of-the-art” imaging technologies.

References: 1: Ueno T, et al. Transplant Int. 2016, 2: Batal I, et al. JASN 2015

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