Id1 expression promotes peripheral CD4+ T cell proliferation and survival upon TCR activation without co-stimulation.

•Id1 expression enables naïve T cell proliferation without anti-CD28 co-stimulation.•Id1 expression facilitates T cells survival when stimulated with anti-CD3.•Elevation of IL-2 production by Id1 contributes increased proliferation and survival.•Id1 potentiates NF-κB activation by anti-CD3 stimulation.