Project description:Camelids are capable of producing both conventional tetrameric antibodies (Abs) and dimeric heavy-chain antibodies (HCAbs). While B cells generating these two types of Abs exhibit distinct B-cell receptors (BCRs), it remains unclear whether these two B cell populations differ in their phenotypes and developmental processes. Here, we collected eight PBMC samples before and after immunization from four Bactrian camels and conducted single-cell 5’ RNA sequencing. We characterized the functional subtypes and differentiation trajectories of circulating B cells in camels, including native B cells, memory B cells, intermediate B cells, atypical B cells, and plasma cells. Additionally, we reconstructed single-cell BCR sequences and revealed the IGHV and IGHC gene types. We found that B cells with variable genes of HACbs (VHH) were widely present in various functional subtypes and showed highly overlapping differentiation trajectories to B cells with variable genes of conventional Abs (VH). After immunization, the transcriptional changes in VHH+ and VH+ B cells were also largely consistent. Our study not only elucidates the cellular context of HCAb production in camels, but also lays the foundation for the development of single B cell-based nanobody screening.
Project description:In response to antigen challenge, human B cells clonally expand, undergo selection and differentiate within secondary lymphoid tissues to produce mature B cell subsets and high affinity antibodies necessary for an effective immune response. However, the interplay between affinity, antibody class and different B cell fates has proved challenging to decipher in primary human tissue. We have applied an integrated analysis of bulk and single-cell antibody repertoires paired with single-cell transcriptomics of human B cells from a model secondary lymphoid tissue. Specifically, here we have performed bulk B cell repertoire sequencing of the immunoglobulin heavy chain (IgH) for sorted B cell subsets from paediatric tonsil tissue. Matched single-cell gene expression and single-cell VDJ data are also available for the same patient donors.
