EFB Dengue Literature Review

BLIMP-1

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BLIMP-1

Overview

BLIMP-1 (B Lymphocyte-Induced Maturation Protein 1; encoded by PRDM1) is an IRF4-induced transcriptional repressor that silences B cell programmes and induces plasma cell differentiation. BLIMP-1 expression is a hallmark of committed PC fate. In DN2 and aNAV B cells, BLIMP-1 is upregulated at both mRNA and protein level, and the PRDM1 locus shows open chromatin by ATAC-seq — indicating these populations are epigenetically poised for PC differentiation.

Key Points from Literature

  • Elevated in DN2 and aNAV: BLIMP-1 protein (flow cytometry MFI) is higher in aNAV and DN2 cells than in rNAV, SWM, and DN1 (p<0.001). Only PC have higher expression (see Jenks2018 - DN2 B Cells and EF Pathway in SLE, flow cytometry n=4).

  • PRDM1 transcription: PRDM1 mRNA is upregulated in DN2 relative to rNAV cells (see Jenks2018 - DN2 B Cells and EF Pathway in SLE, RNA-seq).

  • Epigenetic priming: ATAC-seq demonstrates opening of the PRDM1 locus in aNAV and DN2 cells — chromatin accessibility consistent with poised transcription (see Jenks2018 - DN2 B Cells and EF Pathway in SLE).

  • BACH2 silencing enables BLIMP-1: BACH2, the main negative regulator of PRDM1 transcription, is absent in DN2 and aNAV cells. Removal of BACH2 repression allows BLIMP-1 upregulation (see Jenks2018 - DN2 B Cells and EF Pathway in SLE; see also BACH2).

  • BLIMP-1/PRDM1 pathway operative in COVID-19 EF ASCs: The massive germline-dominant ASC expansion in severe COVID-19 — with >50% unmutated VH, ongoing CSR, and EF cellular hallmarks (aN/DN2/DN3 expansion) — is consistent with BLIMP-1-driven terminal differentiation of naive-derived precursors via the EF pathway, as defined by the PRDM1 locus opening in DN2/aNAV cells (see Woodruff2020 - EF B Cell Responses in COVID-19, n=17 COVID-19 prospective cohort; repertoire data from n=1 single-cell + n=2 bulk V(D)J).

  • PRDM1/Blimp-1 is part of the DN2 ASC-poised TF network: In the comprehensive SLE DN2 characterisation, overexpression of PRDM1/Blimp-1 alongside IRF4 and Zbtb32 positions DN2 cells for rapid ASC differentiation — a programme confirmed across mouse and human ABC (see Sanz2025 - Human Atypical B Cells Overview, review).

  • PRDM1 promoter shows progressive demethylation and increased accessibility across B cell differentiation: RRBS and ATAC-seq data confirmed increasing PRDM1 promoter accessibility and decreasing DNA methylation from resting naive through to DN2 and switched memory, most pronounced in DN2. This epigenetic priming was accompanied by transcriptional upregulation of PRDM1 and SLAMF7 (see Scharer2019 - Epigenetic Programming in SLE B Cells, RRBS + ATAC-seq + RNA-seq, n=9 SLE + n=12 HC).

Contradictions & Debates

None documented in current wiki sources.

IRF4, BACH2, DN2 B Cell, Activated Naive B Cell, Plasmablast, Extrafollicular Response

Sources

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