The balance between eliminating threats and preserving healthy tissue represents one of immunology's most critical challenges, with profound implications for autoimmune disease prevention and cancer immunotherapy effectiveness. This mathematical framework reveals how cytotoxic T cells achieve this precision through sophisticated feedback control mechanisms rather than simple activation thresholds. The research demonstrates that CD8+ T cells operate as feedback-controlled systems, with response speed and magnitude emerging from cellular decision rules that integrate pathogen recognition signals with self-tolerance checkpoints. These control mechanisms allow T cells to calibrate their cytotoxic response intensity based on threat assessment, explaining how the same cells can mount vigorous responses against infections while maintaining restraint against healthy tissue. The feedback loops involve both positive amplification circuits that accelerate pathogen clearance and negative regulatory circuits that prevent excessive tissue damage. This control theory approach to T cell biology offers fresh insights into why some individuals develop autoimmune conditions while others maintain robust pathogen resistance. The findings suggest that therapeutic interventions targeting these feedback mechanisms could enhance cancer immunotherapy by releasing controlled cytotoxic responses, or conversely, treat autoimmune diseases by strengthening regulatory feedback loops. However, the mathematical modeling relies heavily on simplified cellular interactions that may not capture the full complexity of tissue microenvironments. The work represents a conceptual advance in understanding immune system engineering principles, potentially informing next-generation immunotherapies that fine-tune rather than broadly suppress or activate T cell responses.