CD4 T cells are essential for immunity to tuberculosis because they produce cytokines, including interferon-γ. Whether CD4 T cells act as “helper” cells to promote optimal CD8 T cell responses during Mycobacterium tuberculosis is unknown. Using two independent models, we show that CD4 T cell help enhances CD8 effector functions and prevents CD8 T cell exhaustion. We demonstrate synergy between CD4 and CD8 T cells in promoting the survival of infected mice. Purified helped, but not helpless, CD8 T cells efficiently restrict intracellular bacterial growth in vitro. Thus, CD4 T cell help plays an essential role in generating protective CD8 T cell responses against M. tuberculosis infection in vitro and in vivo. We infer vaccines that elicit both CD4 and CD8 T cells are more likely to be successful than vaccines that elicit only CD4 or CD8 T cells.

CD4 T 细胞对结核病免疫至关重要，因为它们产生细胞因子，包括干扰素-γ。CD4 T 细胞是否充当“辅助”细胞以促进结核分枝杆菌期间的最佳 CD8 T 细胞反应尚不清楚。使用两个独立的模型，我们表明 CD4 T 细胞有助于增强 CD8 效应器功能并防止 CD8 T 细胞衰竭。我们展示了 CD4 和 CD8 T 细胞在促进受感染小鼠存活方面的协同作用。纯化的 CD8 T 细胞有助于但并非无助于体外有效限制细胞内细菌的生长。因此，CD4 T 细胞帮助在体外和体内产生针对结核分枝杆菌感染的保护性 CD8 T 细胞反应中发挥重要作用. 我们推断同时引发 CD4 和 CD8 T 细胞的疫苗比仅引发 CD4 或 CD8 T 细胞的疫苗更有可能成功。