EFB Dengue Literature Review

CD11c

6 min read

CD11c

Overview

CD11c (encoded by ITGAX) is an alpha integrin primarily expressed on dendritic cells and monocytes. On B cells, high CD11c surface expression marks extrafollicular plasmablasts, age-associated B cells (ABCs), and the DN2 B cell subset. CD11c is one of the defining markers of the DN2 phenotype (IgD⁻CD27⁻CXCR5⁻CD21⁻CD11c⁺) and is used to discriminate DN2 from DN1 cells.

Key Points from Literature

  • DN2 cells are CD11c bright: CD11c is highly expressed on DN2 cells and aNAV cells but low/absent on DN1, SWM, and rNAV. CD11c expression validated at both RNA (ITGAX) and protein level, with complete concordance (see Jenks2018 - DN2 B Cells and EF Pathway in SLE, RNA-seq + flow cytometry).

  • Gating utility: CXCR5 vs. CD11c dot plots on IgD⁻CD27⁻ cells cleanly separate DN1 (CXCR5⁺CD11c^lo) from DN2 (CXCR5⁻CD11c^hi). CD21 vs. CD11c provides equivalent discrimination (see Jenks2018 - DN2 B Cells and EF Pathway in SLE).

  • Shared with aNAV cells: aNAV cells (IgD⁺CD27⁻CXCR5⁻) are also CD11c bright — CD11c expression links these two populations phenotypically and transcriptionally (see Jenks2018 - DN2 B Cells and EF Pathway in SLE).

  • Murine parallel: Murine CD11c^bright ABCs are T-bet-dependent and important for anti-viral IgG2a responses and autoimmunity. Human DN2 cells share this CD11c^bright T-bet⁺ phenotype (see Jenks2018 - DN2 B Cells and EF Pathway in SLE, citing Rubtsova et al. 2015).

  • In vitro-generated DN2 cells upregulate CD11c: rNAV cells stimulated with TLR7 + IFN-γ + IL-21 upregulate CD11c as they differentiate into aNAV and DN2 cells, confirming that CD11c acquisition is part of the EF differentiation programme (see Jenks2018 - DN2 B Cells and EF Pathway in SLE).

  • CD11c is heterogeneous across B cell compartments: CD11c expression is not confined to DN2 cells — it is found on aNAV cells (highest), DN2, and at lower levels on a subset of CD27⁺ switched memory cells (activated ABC memory, both resting CD21⁺ and activated CD21lo fractions). Using CD11c alone to identify “ABC” or “AtB” therefore captures a heterogeneous mix of populations with different origins and functions (see Sanz2025 - Human Atypical B Cells Overview, review, Table 1 and Figure 2).

  • CD11c can be induced without T-bet or IFN-γ: CD11c and other ABC markers can be upregulated in vitro through diverse activation conditions in the absence of IFN-γ stimulation or T-bet expression. CD11c is therefore not a reliable proxy for T-bet⁺ identity (see Sanz2025 - Human Atypical B Cells Overview, review).

  • T-bet/FcRL5 can substitute for CD11c in gating: CXCR5 vs. CD11c, CXCR5 vs. T-bet, and CXCR5 vs. FcRL5 staining identify similar populations, providing practical flexibility for panel design (see Sanz2025 - Human Atypical B Cells Overview, review, Figure 2C).

  • CD11c expression validated in acute viral infection: In COVID-19, intracellular staining (n=4 ICU patients) confirmed that aN and DN2 cells had the highest T-bet and CD11c expression of any B cell population, above rN, DN1, and DN3. CD11c expression on UMAP projections cleanly demarcated the aN/DN2 region (ROI 1) that distinguished ICU from outpatient and healthy B cell profiles (see Woodruff2020 - EF B Cell Responses in COVID-19, spectral FCM + intracellular staining).

  • CD11c used in DN1/DN2/DN3 gating in 24-marker panel: The Woodruff2020 Table 1 gating scheme uses CD11c vs. CD21 within the DN gate to resolve DN1 (CD11c⁻CD21⁺), DN2 (CD11c⁺CD21⁻), and DN3 (CD11c⁻CD21⁻). This is the standardised gating applicable to spectral panels for EF pathway studies (see Woodruff2020 - EF B Cell Responses in COVID-19, Table 1).

  • CD11c⁺ marks EF B cells in acute dengue: CD21⁻CD11c⁺ B cells within the IgD⁻CD27⁻ (DN) gate are significantly expanded during acute dengue infection. This is the first demonstration of CD11c⁺ EF-phenotype B cells in dengue, validating the SLE/COVID-19 DN2 phenotype in a third disease context. CD11c was used alongside CD21 to identify EF B cells without CXCR5 staining (see Ansari2025 - Peripheral T Helper Subset Drives B Cell Response in Dengue, multi-color FCM, n=170 acute dengue).

  • CD11c is the best single surface marker for the alternative B cell lineage by CITE-seq: Combined transcriptome + surface protein measurement (CITE-seq) on >12,000 B cells showed that CD11c protein expression most cleanly identified the transcriptomically-defined alternative lineage (atBC1, atBC2, atBC3, MBC1), outperforming CD21⁻CD27⁻ gating which captured only 44.7% of atBC1 cells. This provides the strongest primary-source evidence that CD11c should replace or supplement CD21⁻CD27⁻ as the principal gating marker for this population (see Sutton2021 - Alternative Lineage B Cells in Vaccination and Infection, n=4, CITE-seq + 10x Chromium).

  • CD11c⁺ DCs interact with B cells at extrafollicular sites (murine precedent). In the foundational William2002 EF SHM study, CD11c⁺ dendritic cells were abundant within RF B cell clusters at the T zone–red pulp border and showed close physical interaction with Id⁺ B cells, in contrast to GCs where CD11c⁺ DCs are rare. This established CD11c⁺ DCs as a cellular component of the EF microenvironment, distinct from FDCs that define the GC niche. In the context of this wiki’s B cell focus, CD11c on B cells marks EF-pathway cells (DN2/aNAV), while CD11c on DCs marks the innate cellular partners at EF sites — both uses reflect the extrafollicular niche (see William2002 - Extrafollicular Somatic Hypermutation in Autoimmune Mice, IHC of splenic sections, MRL/lpr mice).

  • CD11c is the integrin that helped define the ABC, and IL-21 is its primary inducer. CD11c (with T-bet) was one of the two markers used to define age-associated B cells in aged mice; in the ABC/atypical differentiation programme IL-21 robustly induces CD11c whereas IFN-γ primarily drives T-bet — a clean division of labour between the two cytokines that cooperate (with TLR7/9) to generate the phenotype (see Lamprinou2026 - ABCs and DN B Cells, opinion, citing Hao 2011 / Naradikian 2016 / Liu 2024). This complements the wiki’s existing evidence that CD11c can also be induced without IFN-γ/T-bet (Sanz2025) — i.e., CD11c acquisition is cytokine-context-dependent.

Contradictions & Debates

None documented in current wiki sources.

DN2 B Cell, Age-Associated B Cell, Atypical B Cell, Activated Naive B Cell, T-bet, IL-21, CXCR5, Double-Negative B Cell, Extrafollicular Response, FCRL5, CXCR3, CD21, Peripheral Helper T Cell

Sources

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