Figure 2.

Stimulation of TCR and CD28 causes a metabolic shift in naïve CD4 T cells. T cell receptor (TCR) stimulation by peptide presented on major histocompatibility complex-II (MHC-II) (A) will increase calcium (Ca²⁺) entry into the cytoplasm through store operated calcium entry (SOCE) channels (B) increasing mitochondrial-derived superoxide $(O_2^{·-})$ generation (C). Oxidative phosphorylation (OxPhos) will promote interleukin (IL)-2 expression by hydrogen peroxide (H₂O₂) signaling (D). Simultaneously, CD28 will upregulate Glut1 expression on the cell membrane increasing glucose uptake shifting metabolism away from OxPhos to glycolysis to support rapid proliferation (E).