Complexity of the human memory B-cell compartment is determined by the versatility of clonal diversification in germinal centers

The complexity of the human memory B-lymphocyte compartment is a key component to depict and understand adaptive immunity. Despite numerous prior investigations, the generation of certain memory B-cell subsets, the dependency on T-cell help, and the composition, size, and diversity of clonal expansions are either poorly understood or debated. Here we provide an extensive and tightly controlled immunoglobulin heavy chain variable (IGHV) gene repertoire analysis of four main human memory B-cell subpopulations, revealing that an ordered diversification in germinal centers determines a highly versatile memory B-cell compartment in humans with surprisingly many very large B-cell clones.