A failed HIV vaccine trial suggested that CD4⁺ T helper cell activation can abrogate protective vaccine effects because these cells, albeit required for an immune response, constitute ideal targets for HIV. Comparing two similar vaccination protocols, Sauermann et al. (e01120-17) showed that acquisition of challenge virus is significantly delayed only in the group with low levels of vaccine-specific CD4⁺ T cells and high levels of activated CD8⁺ T cells. Both the vaccine vector and the route of immunization affected the level of CD4⁺ T-cell responses. Activated T helper cells thus represent a major hurdle for HIV vaccine development.

Number of challenge virus exposures correlated with vaccine-induced virus-specific CD4⁺ T-cell responses and activated CD8⁺ T-cell levels.

一项失败的艾滋病毒疫苗试验表明，CD4 ⁺ T辅助细胞的活化可以消除保护性疫苗的作用，因为这些细胞尽管是免疫应答所必需的，但却是艾滋病毒的理想靶标。比较两个类似的疫苗接种方案，Sauermann等。（e01120-17）表明，仅在疫苗特异性CD4 ⁺ T细胞水平低和活化CD8 ⁺ T细胞水平低的组中，攻击病毒的获取才显着延迟。疫苗载体和免疫途径都会影响CD4 ⁺ T细胞反应的水平。因此，活化的T辅助细胞代表了HIV疫苗开发的主要障碍。

挑战病毒暴露的数量与疫苗诱导的病毒特异性CD4 ⁺ T细胞反应和活化的CD8 ⁺ T细胞水平相关。