Quick antigen detection is essential for our adaptive immune system to function properly.  We model the T-cell migration and their search for antigens from binding with antigen-presentation cells (APC) in a lymph node. A successful search must encounter the cognate antigens from many APCs within a stochastic time span (before departure from the lymph node). As such, we study the first passage time statistic of binding and exiting events of T-cells in various setting, for example, multi-stage binding and spatially heterogeneous distribution of APC. This is a joint work with Ikchang Cho, Maria D’Orsogna and Tom Chou.