Large-scale Analysis of 2,152 dataset reveals key features of B cell biology and the antibody repertoire

Antibody repertoiresequencing (Ig-seq) has been widely used in studying humoral responses, with promising results. However, the promise of Ig-seq has not yet been fully realized, and key features of the antibody repertoireremain elusive or controversial. To clarify these key features, we analyzed 2,152 high-quality heavy chain antibody repertoires, representing 582 donors and a total of 360 million clones. Our study revealed that individuals exhibit very similar gene usage patterns for germline V, D, and J genes and that 53 core V genes contribute to more than 99% of the heavy chain repertoire. We further found that genetic background is sufficient but not necessary to determine usage of V, D, and J genes. Although gene usage pattern is not affected by age, we observed a significant sex preference for 24 V genes, 9 D genes and 5 J genes, but found no positional bias for V-D and D-J recombination. In addition, we found that the number of observed clones that were shared between any two repertoiresfollowed a linear model and noted that the mutability of hot/cold spots and single nucleotides within antibody genes suggested a strand-specific somatic hypermutationmechanism. This population-level analysis resolves some critical characteristics of the antibody repertoireand thus may serve as a reference for research aiming to unravel B cell-related biology or diseases. The metrics revealed here will be of significant value to the large cadre of scientists who study the antibody repertoire.