CD8+ lymphocytes in immunity against tuberculosis.

Tuberculosis (TB) is a major global health threat. Deep knowledge of the immune responses against Mycobacterium tuberculosis (Mtb) is crucial for developing effective interventions. Data support that both innate and adaptive CD8+ lymphocytes contribute to protective immunity in Mtb infections, commonly attributed to the expression of cytotoxic effectors. They can also produce proinflammatory cytokines that activate macrophages to enhance antimycobacterial responses. However, the roles and functions of the various CD8+ lymphocyte subsets in TB protection and pathogenesis are complex, as excessive activation can lead to tissue damage and exacerbate disease severity, while CD8+ lymphocytes with anti-inflammatory functions may limit inflammation and damage. Understanding the heterogeneity of CD8+ lymphocyte responses and dynamics in TB can provide critical insights for designing efficacious vaccines and immunotherapies while minimizing immunopathology. This review focuses on the current understanding of roles for different CD8+ lymphocyte subsets in responses against Mtb and implications for novel vaccine and therapeutic development.