Identification of immune subsets with distinct lectin binding signatures using multi-parameter flow cytometry: correlations with disease activity in systemic lupus erythematosus

• Published in: Frontiers in immunology Vol. 15; p. 1380481
• Main Authors: Szabó, Enikő, Faragó, Anna, Bodor, Gergely, Gémes, Nikolett, Puskás, László G., Kovács, László, Szebeni, Gábor J.
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 07.05.2024
• Subjects: Adult; Female; flow cytometry; Flow Cytometry - methods; Galectins - immunology; Galectins - metabolism; glycobiology of SLE; Glycosylation; Humans; Immunology; immunophenotyping; lectin binding; Lectins - immunology; Lectins - metabolism; Leukocytes, Mononuclear - immunology; Leukocytes, Mononuclear - metabolism; Lupus Erythematosus, Systemic - immunology; Lupus Erythematosus, Systemic - metabolism; Male; Middle Aged; Protein Binding; Severity of Illness Index; systemic lupus erythematosus; Young Adult; systemic lupus erythematosus; flow cytometry; lectin binding; glycobiology of SLE; immunophenotyping
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2024.1380481

Cell surface glycosylation can influence protein-protein interactions with particular relevance to changes in core fucosylation and terminal sialylation. Glycans are ligands for immune regulatory lectin families like galectins (Gals) or sialic acid immunoglobulin-like lectins (Siglecs). This study delves into the glycan alterations within immune subsets of systemic lupus erythematosus (SLE). Evaluation of binding affinities of Galectin-1, Galectin-3, Siglec-1, lectin (AAL, recognizing core fucosylation), and agglutinin (SNA, specific for α-2,6-sialylation) was conducted on various immune subsets in peripheral blood mononuclear cells (PBMCs) from control and SLE subjects. Lectin binding was measured by multi-parameter flow cytometry in 18 manually gated subsets of T-cells, NK-cells, NKT-cells, B-cells, and monocytes in unstimulated resting state and also after 3-day activation. Stimulated pre-gated populations were subsequently clustered by FlowSOM algorithm based on lectin binding and activation markers, CD25 or HLA-DR. Elevated AAL, SNA and CD25 /CD25 SNA binding ratio in certain stimulated SLE T-cell subsets correlated with SLE Disease Activity Index 2000 (SLEDAI-2K) scores. The significantly increased frequencies of activated AAL Siglec-1 NK metaclusters in SLE also correlated with SLEDAI-2K indices. In SLE, activated double negative NKTs displayed significantly lower core fucosylation and CD25 /CD25 Siglec-1 binding ratio, negatively correlating with disease activity. The significantly enhanced AAL binding in resting SLE plasmablasts positively correlated with SLEDAI-2K scores. Alterations in the glycosylation of immune cells in SLE correlate with disease severity, which might represent potential implications in the pathogenesis of SLE.