IgM, IgG, and IgA Influenza-Specific Plasma Cells Express Divergent Transcriptomes

Abstract

Ab-secreting cells (ASC) or plasma cells are essential components of the humoral immune system. Although Abs of different isotypes have distinct functions, it is not known if the ASC that secrete each isotype are also distinct. ASC downregulate their surface BCR upon differentiation, hindering analyses that couple BCR information to other molecular characteristics. In this study, we developed a methodology using fixation, permeabilization, and intracellular staining coupled with cell sorting and reversal of the cross-links to allow RNA sequencing of isolated cell subsets. Using hemagglutinin and nucleoprotein Agspecific B cell tetramers and intracellular staining for IgM, IgG, and IgA isotypes, we were able to derive and compare the gene expression programs of ASC subsets that were responding to the same Ags following influenza infection in mice. Intriguingly, whereas a shared ASC signature was identified, each ASC isotype-specific population expressed distinct transcriptional programs controlling cellular homing, metabolism, and potential effector functions. Additionally, we extracted and compared BCR clonotypes and found that each ASC isotype contained a unique, clonally related CDR3 repertoire. In summary, these data reveal specific complexities in the transcriptional programming of Ag-specific ASC populations.

Single-cell BCR and transcriptome analysis after influenza infection reveals spatiotemporal dynamics of antigen-specific B cells

“…Validating the observed differences, PB and GC transcriptional profiles appeared largely similar between organs (Figures S2D-S2K). The only detected difference was between IgA PB and others, as previously reported (Figure S2E) (Neu et al, 2019;Price et al, 2019). Thanks to our approach, we detected transcriptional differences in HA-Bmem between germline (likely GC-independent) and mutated (GC-dependent) cells, suggesting long term functional differences, depending on cell origin (Figures 3G and S2B).…”

Single cell BCR and transcriptome analysis after respiratory virus infection reveals spatiotemporal dynamics of antigen-specific B cell responses

“…Validating the observed differences, PB and GC transcriptional profiles appeared largely similar between organs ( Fig S2D-K). The only detected difference was between IgA PB and others, as previously reported ( Fig S2E) (Neu et al, 2019;Price et al, 2019). Thanks to the power of our approach, we detected transcriptional differences in Bmem and PB between germline (GCindependent) and mutated (GC-dependent) cells, suggesting long term functional differences, depending on cell origin (Fig 3G and Fig S2B and Fig S2L).…”

The gene regulatory network controlling plasma cell function

“…This analysis also revealed that despite differences in anatomical location, life span and proliferation status, plasma cells from the bone marrow and spleen, as well as splenic plasmablasts share a core transcriptional signature 11 . The expression of this gene signature is also largely independent of Ig isotype, with the exception of genes influencing homing and migration, which are differentially expressed between IgM + , IgG + and IgA + ASC populations 12 . In addition to the known regulators of ASC differentiation and function, most notably Irf4 , Prdm1 and Xbp1 (discussed below), genes within this signature encode proteins involved in a diverse range of cellular processes.…”