γδ T cell-derived IL-4 initiates CD8 T cell immunity

Abstract

Dendritic cells (DCs) are pivotal for initiating adaptive immunity, a process triggered by the activation of DCs via pathogen products or damage. Immunization with sporozoites from Plasmodium leads to CD8+ T cell priming in a response initiated by collaboration between conventional type 1 DCs (cDC1s) and γδ T cells. Here we show that Vγ1+ γδ T cells have an initiating role by directly supplying interleukin-4 (IL-4). IL-4 and interferon-γ (IFNγ) synergize with CD4+ T cell-derived CD40L to induce IL-12 production by cDC1. Both IL-12 and IL-4 then directly signal responding CD8+ T cells and drive enhanced IL-12 receptor expression and expansion. This study shows how Vγ1+ γδ T cells can initiate..