Recent findings regarding let-7 in immunity

Let-7 was one of the first microRNAs discovered in Caenorhabditis elegans. It exerts various biological functions, and shows strong evolutionary conservation from nematodes to humans. Recent research findings identify the let-7 cluster as a crucial player in the regulation of B-cell antibody production and macrophage responses. Since increasing evidence supports the let-7 cluster's role in immune system regulation, here we review the latest knowledge regarding the activities of let-7 in both innate and adaptive immune cells—including macrophages, B cells, and subsets of T cells—and the targets regulated by members of the let-7 family. This summary of knowledge acquired from collective studies will help guide future physiological and pathological studies to further elucidate the potential uses of this microRNA in immunity and other different biological outputs.