EFB Dengue Literature Review

SLAMF7

4 min read

SLAMF7

Overview

SLAMF7 (Signaling Lymphocytic Activation Molecule Family member 7; also CD319, CS1, CRACC) is a cell surface glycoprotein expressed on plasma cells and, notably, on DN2 and aNAV B cells. It is already an approved therapeutic target in multiple myeloma (elotuzumab). Its expression on DN2/aNAV cells but not on resting naive or conventional memory B cells makes it a candidate for selective therapeutic targeting of ABC/DN2 populations.

Key Points from Literature

  • Upregulated on DN2 and aNAV: SLAMF7 is expressed on DN2 and aNAV B cells but not on other B cell subsets (resting naive, switched memory, DN1). It is typically a plasma cell marker, and its upregulation on DN2/aNAV cells is consistent with their pre-plasmablast identity (see Jenks2018 - DN2 B Cells and EF Pathway in SLE, RNA-seq).

  • Part of the extended DN2/aNAV phenotype: The full shared phenotype of aNAV and DN2 cells includes SLAMF7⁺ alongside CD27⁻, CD21lo, CXCR5⁻, CD11c⁺⁺, T-bet⁺⁺, FcRL5⁺ (see Sanz2025 - Human Atypical B Cells Overview, review).

  • Therapeutic target candidate: SLAMF7 is one of two preferred targets (alongside FCRL5) for selective ABC/DN2 depletion within the B cell compartment. Elotuzumab (anti-SLAMF7) is already FDA-approved for relapsed/refractory multiple myeloma, providing a clinically validated platform for repurposing in autoimmunity (see Sanz2025 - Human Atypical B Cells Overview, review).

  • Chromatin accessibility evidence: In SWEF-deficient lupus mice, ABC chromatin shows enhanced accessibility in areas enriched for T-bet, AP-1, and IRF4 motifs — the same motifs enriched in human SLE DN2 cells. SLAMF7 upregulation on DN2/aNAV is part of this coordinated epigenetic programme (see Sanz2025 - Human Atypical B Cells Overview).

  • ★ [2026-08-27] SLAMF7 is expressed by both DN2 and DN3, at RNA and protein level — and therefore cannot separate them. Flow-cytometric MFI in IgG4-related disease (n=4): DN2 2123 > DN3 1536 > DN4 956 > DN1 895. SLAMF7 sits inside a broader cytotoxic gene module shared by DN2 and DN3 (GZMA, GZMH, GZMB, GNLY, NKG7, KLRB1, KLRD1, KLRF1, FCGR3A) (see Allard-Chamard2023 - DN3 B Cells Infiltrate Inflamed Tissues, n=4 bulk RNA-seq + flow validation).

  • [2026-08-27] SLAMF7 was used as a tissue stain for “activated DN2/3” cells, and this is a real limitation of that paper’s tissue argument. Multi-colour immunofluorescence of IgG4-RD salivary gland stained CD19/IgD/CD27/SLAMF7 to show activated DN B cells contacting CD4⁺ T cells. Because both DN2 and DN3 are SLAMF7⁺, the stain establishes “activated DN” but not which subset; the paper’s DN3 attribution is made by elimination (DN2 being rare in tissue), not by measurement. The same figure shows conjugates involving both SLAMF7⁺ and SLAMF7⁻ DN cells (see Allard-Chamard2023 - DN3 B Cells Infiltrate Inflamed Tissues, n=4 tissue IF).

  • SLAMF7 appears in Table 1 as part of the shared DN2 / activated-naive activation signature, never alone. Both DN2 and activated naive are given as T-bet⁺CD11c⁺FcRL5⁺SLAMF7⁺CXCR5⁻; DN1 carries none of these. The review groups SLAMF7 with CD11c and FcRL5 as “activation markers” rather than lineage markers, which places it under the same activation-not-identity caution the review applies to CD21, CD11c and T-bet (see Sanz2019 - Consistent Classification of Human B Cell Populations, review — no original data).

Contradictions & Debates

  • Is SLAMF7 restricted to DN2 and aNAV, or expressed across the DN compartment? Jenks2018 - DN2 B Cells and EF Pathway in SLE reports SLAMF7 on DN2 and aNAV but not on resting naive, switched memory or DN1. Allard-Chamard2023 - DN3 B Cells Infiltrate Inflamed Tissues measured protein MFI across sorted subsets (n=4) and found all four DN subsets positive — DN2 2123 > DN3 1536 > DN4 956 > DN1 895. The readings are reconcilable if Jenks’ “not expressed” means not resolvable above background on that panel rather than absent: Allard-Chamard’s DN1 value is the lowest of the four and the comparison is relative MFI, not a positivity call. ⚠ The practical consequence stands either way — SLAMF7 cannot be used to separate DN2 from DN3.

DN2 B Cell, Activated Naive B Cell, FCRL5, Plasmablast, Extrafollicular Response, DN3 B Cell, Multi-color Immunofluorescence

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