Human T-bet governs the generation of a distinct subset of CD11chighCD21low B cells

Sci Immunol. 2022 Jul 22;7(73):eabq3277. doi: 10.1126/sciimmunol.abq3277. Epub 2022 Jul 22.


High-level expression of the transcription factor T-bet characterizes a phenotypically distinct murine B cell population known as "age-associated B cells" (ABCs). T-bet-deficient mice have reduced ABCs and impaired humoral immunity. We describe a patient with inherited T-bet deficiency and largely normal humoral immunity including intact somatic hypermutation, affinity maturation and memory B cell formation in vivo, and B cell differentiation into Ig-producing plasmablasts in vitro. Nevertheless, the patient exhibited skewed class switching to IgG1, IgG4, and IgE, along with reduced IgG2, both in vivo and in vitro. Moreover, T-bet was required for the in vivo and in vitro development of a distinct subset of human B cells characterized by reduced expression of CD21 and the concomitantly high expression of CD19, CD20, CD11c, FCRL5, and T-bet, a phenotype that shares many features with murine ABCs. Mechanistically, human T-bet governed CD21loCD11chi B cell differentiation by controlling the chromatin accessibility of lineage-defining genes in these cells: FAS, IL21R, SEC61B, DUSP4, DAPP1, SOX5, CD79B, and CXCR4. Thus, human T-bet is largely redundant for long-lived protective humoral immunity but is essential for the development of a distinct subset of human CD11chiCD21lo B cells.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • B-Lymphocytes*
  • CD11c Antigen / metabolism
  • Gene Expression Regulation
  • Humans
  • Immunoglobulin G
  • Lipoproteins / metabolism
  • Lymphocyte Activation
  • Mice
  • Plasma Cells*


  • Adaptor Proteins, Signal Transducing
  • CD11c Antigen
  • Dapp1 protein, mouse
  • Immunoglobulin G
  • Lipoproteins