scRNA + BCR-seq identifies proportions and characteristics of dual BCR B cells in the peritoneal cavity of mice and peripheral blood of healthy human donors across different ages.

The increased incidence of inflammatory diseases, infectious diseases, autoimmune disorders, and tumors in elderly individuals is closely associated with several well-established features of immunosenescence, including reduced B cell genesis and dampened immune responses. Recent studies have highlighted the critical role of dual receptor lymphocytes in tumors and autoimmune diseases. This study utilized shared data generated through scRNA-seq + scBCR-seq technology to investigate the presence of dual receptor-expressing B cells in the peritoneum of mouse and peripheral blood of healthy volunteers, and whether there are age-related differences in dual receptor B cell populations. In the peritoneum of mice, a high proportion of B cells expressing dual receptors, predominantly dual κ chains, was observed. Notably, there was an increase in dual BCR B cells in elderly mice. Subsequent analysis revealed that the elevated dual BCR B cells in elderly mice primarily originated from B1 cells.Consistent with the results we observed in healthy volunteers of different ages. Furthermore, these cells exhibited differential expressed genes compared to single BCR B cells, including Vim, Ucp2, and Zcwpw1.These findings support a hypothesis that age-related immune changes encompass not only alterations in B cell numbers but also qualitative changes in BCR diversity. Further exploration of the elevated dual BCR B cells in the elderly population can elucidate their function and their association with immune tolerance, revealing their potential role in maintaining immune surveillance and responding to age-related immune challenges.