The downside of diversity

Abstract

Human Immunology The adaptive immune system exemplifies the benefits of diversity, allowing for individual responses to specific pathogens. Natural killer (NK) cells are also diverse at the single-cell level, but the contribution of this diversity to NK cell–mediated immunity has been unclear. Strauss-Albee et al. found that unlike adaptive immune cells, human NK cell diversity is lower at birth than in adults. Moreover, the diversification that results from antiviral responses decreases the flexibility of future responses. Indeed, high NK cell diversity was associated with increased risk of HIV-1 acquisition in African women. Sci. Transl. Med. 7 , 297ra115 (2015).