Figure 1.

Canonical three-signal activation model for T cells. Activation is dependent on integration of three signals: 1) recognition by the T-cell receptor (TCR) of an antigen presented as a peptide by the major histocompatibility complex (pMHC) on antigen-presenting cells (APCs); 2) costimulation, which lowers the stimulation threshold of naïve T cells, prevents anergy, and enhances cytokine production; and 3) cytokine signaling along the JAK-STAT pathway, which amplifies the clonal expansion, survival, and differentiation of T cells. These converging cellular signaling cascades influence the activation and differentiation status of T lymphocytes, in this case, CD8+ T cells. Adapted from “Three Signals Required for T cell Activation”, by BioRender.com (2022). Retrieved from https://app.biorender.com/biorender-templates/t-5f7c7b883b9a9000abcf98e4-three-signals-required-for-t-cell-activation.