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

Area of Science:

• Immunology
• Molecular Biology
• Genomics

Background:

• Antibody-secreting cells (ASC), or plasma cells, are crucial for humoral immunity.
• Distinct antibody (Ab) isotypes perform varied functions, but whether ASCs secreting them differ is unknown.
• ASC surface B cell receptor (BCR) downregulation complicates analysis of BCR information with other molecular traits.

Purpose of the Study:

• To develop a method for analyzing gene expression in specific ASC subsets.
• To compare the gene expression programs and BCR clonotypes of ASCs secreting different Ab isotypes.
• To investigate the transcriptional complexity of antigen-specific ASC populations.

Main Methods:

• Developed a novel methodology involving fixation, permeabilization, intracellular staining, and cross-link reversal for RNA sequencing of isolated cell subsets.
• Utilized antigen-specific B cell tetramers and intracellular isotype staining (IgM, IgG, IgA) for ASC subset isolation.
• Employed RNA sequencing and BCR clonotype analysis to compare gene expression and receptor repertoires.

Main Results:

• Identified a shared ASC signature across different isotype-secreting populations.
• Discovered distinct transcriptional programs governing cellular homing, metabolism, and effector functions in each isotype-specific ASC subset.
• Revealed unique, clonally related CDR3 repertoires within each ASC isotype population.

Conclusions:

• Antigen-specific ASC populations exhibit isotype-specific transcriptional complexities.
• ASCs secreting different antibody isotypes possess distinct molecular characteristics and functional programs.
• This research provides new insights into the heterogeneity and regulation of antibody-secreting cells.