Description
The murine thymus produces discrete T cell subsets making either IFN- or IL-17, but the role of the TCR in this developmental process remains controversial. Here we generated a non-transgenic and polyclonal model of reduced TCR expression and signal strength selectively on T cells. Mice haploinsufficient for both CD3 and CD3 (CD3DH) showed normal thymocyte subsets but specific defects in T cell development, namely impaired differentiation of IL-17-producing embryonic V6+ (but not adult V4+) T cells and a marked depletion of IFN--producing CD122+ NK1.1+ (V1-biased) T cells throughout life. As result, adult CD3DH mice showed defective peripheral IFN- responses and were resistant to experimental cerebral malaria. Thus, strong TCR signaling is required within specific developmental windows with distinct V usage and differential cytokine production by effector T cell subsets.