Th1 cell polarization is a process by which naïve CD4⁺ T cells differentiate into Th1 effector cells upon stimulation by antigen and cytokines such as IL-12 and IFN-γ. This process is predominantly governed by the key transcription factor T-bet, which drives the robust production of characteristic cytokines like IFN-γ. Polarized Th1 cells primarily function to activate macrophages and cytotoxic T cells, thereby orchestrating the cell-mediated immune response, which is critical for defending against intracellular pathogen infections.