Structure and duration of contact between dendritic cells and T cells are controlled by T cell activation state.

The adaptive immune response is initiated when naive T cells interact with dendritic cells (DC). However, the physicodynamics as well as the molecules that constitute the contact plane (immunological synapse) between DC and T cells are not well understood. We show here that for the formation of stable conjugates, T cells need to be preactivated by DC in a CD80/86- and antigen dose-dependent manner.

Antigen dose, type of antigen-presenting cell and time of differentiation contribute to the T helper 1/T helper 2 polarization of naive T cells.

Antigenic encounter by T cells induces immunological synapse formation and T-cell activation. Using different concentrations of toxic shock syndrome toxin-1 (TSST-1) as stimulus, we examined the capacities of dendritic cells (DC) and macrophages (Mphi) to prime syngeneic naive T cells. DCs were, under all experimental settings, more efficient than Mphi at clustering T cells.