granulo.site Literature Home cyto.site

Gallery

granulocyte images: illustrations and micrographs. All credits and licenses listed. Click a picture to see it large; click it again to open its paper. The pictures by method and the papers by section are in the library.

Micrographs

Neutrophil in a peripheral blood smear, Wright stain. The multilobed nucleus and pale cytoplasm are characteristic of the circulating PMN.

Bob Blaylock, Wikimedia Commons · CC BY-SA 3.0

source
Neutrophil rolling on endothelium in a postcapillary venule, intravital fluorescence imaging.

Amini, Schemmelmann, Heming et al 2025, JCI Insight. PMID: 40493407. · CC BY 4.0

PMID 40493407
Neutrophil in a peripheral blood smear showing the characteristic segmented nucleus with 3 to 5 lobes.

Dr. Roshan Nasimudeen, Wikimedia Commons · CC BY-SA 3.0

source
Scanning electron micrograph of a human neutrophil (blue) engulfing MRSA bacteria (yellow). The cell extends pseudopods around the bacteria in a classic phagocytic embrace.

National Institutes of Health (NIH) · Public domain

source
Scanning electron micrograph of a neutrophil (orange-brown) with MRSA bacteria (purple). A second image from the NIH SEM series on neutrophil-pathogen interaction.

National Institutes of Health (NIH) · Public domain

source
Scanning electron micrograph of a neutrophil (orange) engaging a Bacillus anthracis chain (green). Taken by Volker Brinkmann, the scientist who discovered neutrophil extracellular traps.

Volker Brinkmann, Wikimedia Commons. PMID: 15001782. · CC BY 2.5

PMID 15001782
Scanning electron micrograph of neutrophil extracellular traps (NETs): fine fibres of decondensed chromatin with embedded granule proteins enmeshing Staphylococcus aureus.

Urban CF et al. 2009, PLoS Pathogens, Wikimedia Commons. PMID: 19876394. · CC BY 2.5

PMID 19876394
Immunofluorescence of NETs: neutrophils (blue DAPI nuclei) releasing decondensed chromatin co-stained with MPO (red) and citrullinated histone H3 (green).

Singh, Zlatar, Munoz-Becerra et al 2024, Cell Communication and Signaling. PMID: 39252008. · CC BY 4.0

PMID 39252008
Transmission electron micrograph of a human neutrophil showing the multilobed nucleus and electron-dense azurophilic granules in the cytoplasm.

Serwas, Huemer, Dieckmann et al 2018, Frontiers in Immunology. PMID: 29651288. · CC BY

PMID 29651288
Immunoelectron micrograph of a neutrophil granule showing immunogold labeling of specific granule contents. Granule populations are distinguished by their electron density and marker proteins.

Serwas, Huemer, Dieckmann et al 2018, Frontiers in Immunology. PMID: 29651288. · CC BY

PMID 29651288
Eosinophil in a peripheral blood smear, Giemsa stain. The bilobed nucleus and large brick-red granules packed with major basic protein are the defining features.

Bobjgalindo, Wikimedia Commons · CC BY-SA 4.0

source
Eosinophil among red blood cells, Giemsa stain. The bright orange-red cytoplasmic granules are visible against the pale erythrocytes.

Dr Graham Beards, Wikimedia Commons · CC BY-SA 3.0

source
Activated eosinophils in idiopathic hypereosinophilic syndrome. Degranulated cells with vacuolated cytoplasm; some show extracellular granule deposits, a hallmark of cytolytic degranulation.

NIAID, Wikimedia Commons · CC BY 2.0

source
Transmission electron micrograph of a human eosinophil showing granules with their characteristic crystalloid core (major basic protein) surrounded by a less-dense matrix.

Neves, Palazzi, Malta et al 2024, Journal of Leukocyte Biology. PMID: 38527801. · CC BY 4.0

PMID 38527801
Transmission electron micrograph showing eosinophil cytolytic degranulation: free extracellular granules with intact crystalloid cores, released by cell lysis rather than classical exocytosis.

Caruso, Caruso, Rigoli et al 2025, Cancers. PMID: 41097776. · CC BY 4.0

PMID 41097776
Extracellular sombrero vesicles associate with FEGs in inflamed tissues. (A-D) Representative electron micrographs showing intact extracellular EoSVs (arrowheads) around or in contact with FEGs in different inflamed tissues of eosinophilic diseases.

Neves, Palazzi, Malta et al 2024, Journal of Leukocyte Biology. PMID: 38527801. · CC BY 4.0

PMID 38527801
Ca2+ Influx activates PAD-4 and calpain-1 and promote neutrophil extracellular trap (NET) formation. A shows chromatin externalization from healthy neutrophils (n > 5) treated with PBS unstimulated, 100 ng/ml phorbol 12-myristate 13-acetate (PMA), or 10 μM calcium ionophore A23187 in the presence and the absence of calcium chelator EGTA. Data were analyzed using Tukey's multiple comparisons tests. Note, the calcium-driven NET formation was abrogated by EGTA. B Microscopic analyses of SYTOX Green stained DNA from neutrophils and NETs at 4 h after stimulation. C Microscopic examination of the swelling of isolated nuclei from neutrophils in the presence and/or absence of PAD4, calpain and calcium. D Morphometry of the nuclear sizes from (C). Note that calcium, PAD4, and calpain-1 act synergistically in decondensation/swelling of nuclei. Tukey's multiple comparisons test was used to evaluate the differences among means. The scale bars are 100 and 50 μm in (B) and (C), respectively.

Singh, Zlatar, Munoz-Becerra et al 2024, Cell Communication and Signaling. PMID: 39252008. · CC BY 4.0

PMID 39252008 · fig. Fig. 1
Changes of CD63 positive granules of primary neutrophils in different pH. a) Exemplary images of polarization effect (strong staining focused near the nuclei) observed in CD63-GFP stained, PMA induced neutrophils. Scale bar 50 um. b-c) Representative images of CD63 (GFP) and Hoechst 33342 stained neutrophils +/- PMA after 0.5 h (b) and 3 h (c) show polarization effect in alkaline pH (at 0.5 h) and the disappearance of the effect at 3 h. Scalebar: 100 um. d-e) Increased number of relative CD63 polarized neutrophils in alkaline pH +/- PMA. Stimulation of neutrophils with PMA results in reduced CD63-GFP signal intensity (normalized to Hoechst signal) independent of the pH. N=4; n=9; Data are presented as box plots with individual data points. Data were compared by 2-way-ANOVA, followed by multiple comparison, **p < 0.01, ***p < 0.001, ****p < 0.0001, #p < 0.05, ##p < 0.01, ###p < 0.001, ####p < 0.0001.

Gobel, Li, Tombaz et al 2026, EXCLI Journal · CC BY 4.0

PMID 42517081 · fig. Figure 7
Structural analysis of differentiated PLB-985 and human neutrophil NETs. SEM images of PLB-985 NETs ( a ) and human NETs ( b ). Scale bars are 2 um. Red circle: spherical particles, either individually or in a series (n >= 3). SEM analysis of NET fibre diameter (( c ), n >= 514) and the diameter of spherical particles in PLB samples (( d ), n = 261). Error bars represent mean +/-SD. **** p < 0.0001. ( c ) The statistical analysis results were obtained using the non-parametric Mann-Whitney test. Experiments were performed independently at least three times using separate cell preparations.

Shi, McPherson, Feller et al 2026, Cells · CC BY 4.0

PMID 41892330 · fig. Figure 4
CIT-013 blocks EET release when plasma membrane integrity is compromised. (A) Representative immunofluorescence images of a non-stimulated eosinophil or eosinophils triggered for EETosis with 2 uM A23187 in the presence of HiLyteTM Fluor 488-conjugated CIT-013 (HL488-CIT-013). The eosinophils activated for EETosis showed chromatin decondensation and a re-organized rounded nucleus in stage 1 of EETosis, nuclear membrane rupture and chromatin spreading within the cytoplasm in stage 2 of EETosis, and plasma membrane rupture and CIT-013 binding to chromatin in stage 3 of the EETosis pathway. Of note, due to technical limitations we were not able to clearly track one specific eosinophil over time and therefore different eosinophils at each stage of the EETosis pathway are shown. (B) More representative immunofluorescence images of eosinophils triggered for EETosis with A23187 in the presence of HiLyteTM Fluor 488-conjugated CIT-013. (C) Representative immunofluorescence images of eosinophils triggered for EETosis with A23187 in the presence of HiLyteTM Fluor 488-conjugated isotype control antibody (HL488-cIgG). Scale bars are 10 um.

Zwiers, Montizaan, Kip et al 2025, Frontiers in Immunology · CC BY 4.0

PMID 40051617 · fig. Figure 5
EETs rich in citrullination are abundantly present in human ECRS tissue. (A) A representative image of nasal polyp tissue stained with hematoxylin and eosin (H&E). (B) Increased magnification of selected area from A representing H&E stain, DNA (blue), and major basic protein (MBP; red). (C) Immunofluorescence images showing DNA (blue) and citrullinated histone H3 (citH3; red). (D) Immunofluorescence images from the same section as shown in (C) with DNA (blue) and CIT-013 epitope citrullinated histone H2A (citH2A) and citH4 (green). (E) Increased magnification of selected area from (D) representing H&E stain, DNA (blue), and citH2A and citH4 (green). White arrowheads indicate CIT-013 epitope colocalization with diffuse extracellular DNA, while black arrowheads indicate the colocalization of diffused extracellular DNA with the observed presence of eosinophils. Scale bars in A, C and D are 50 um and in B and E are 10 um. SL, Sublining; L, Lining.

Zwiers, Montizaan, Kip et al 2025, Frontiers in Immunology · CC BY 4.0

PMID 40051617 · fig. Figure 1
Ultrastructural images of human eosinophils showing non-ETotic cytolysis and early extracellular trap cell death (ETosis). A) A non-ETotic cytolytic eosinophil (E) in patient 1 exhibits a localized expansion of the nuclear envelope (curved arrow), moderately decondensed chromatin, and free extracellular granules (FEGs) (arrows); B) the early ETotic eosinophil (E) in patient 4 shows a notable dilatation of the perinuclear space (arrow), extensively decondensed chromatin, and FEGs (curved arrow)

Caruso, Caruso, Rigoli et al 2025, Exploration of Targeted Anti-tumor Therapy · CC BY 4.0

PMID 40291980 · fig. Figure 1
Giardia intestinalis trophozoites trigger PMN activation, NET formation and phagocytosis in human PMN. (A) PMN-parasite interactions were studied by scanning electron microscopy (SEM). Activated PMN (rough surface) as well as PMN releasing NETs (white arrows) and non-activated PMN (white arrowhead) can be observed in PMN-trophozoite-co-cultures. (B, C) Note released NETs (white arrows) and trophozoites exposing their dorsal surface. (D) Attempt of phagocytosis of G. intestinalis trophozoite from a single PMN (white asterisk). The ventral adhesion disc and multiple flagella of a single G. intestinalis trophozoite can be observed.

Salinas-Varas, Bezerra, Rojas-Baron et al 2026, Frontiers in Immunology · CC BY 4.0

PMID 41798929 · fig. Figure 1
Tumor-derived LRG1 promotes cancer progression by recruiting neutrophils and driving NETosis. (A, B) Representative IHC images and quantification of CD66b+ neutrophil infiltration density in HM+ versus HM- BCa tissues. (C) Transwell assays evaluating the chemotactic effect of tumor-derived LRG1 on isolated human neutrophils. (D) Representative macroscopic images and endpoint tumor weights demonstrating the neutrophil-dependent tumor-promoting effect of LRG1 in vivo, which is effectively rescued by anti-Ly6G antibody depletion. (E) UMAP plot demonstrating the reclustering and annotation of distinct neutrophil subpopulations based on subcluster-specific marker genes from the scRNA-seq cohort. (F) Gene set enrichment scoring of the KEGG NETs pathway across neutrophil subpopulations, highlighting significant enrichment in the NCF2_neu subset. (G) Comparative analysis of the relative proportion of the NCF2_neu subpopulation between normal and BCa tumor tissues. (H) GSVA correlation analysis between the LRG1_tumor meta-program and NCF2_neu infiltration abundance across three independent bulk RNA-seq datasets. (I) ELISA quantification of serum NETs markers (cfDNA, MPO, NE) and their correlation with LRG1 levels. (J) Immunofluorescence staining for MPO and H3Cit in neutrophils directly stimulated with rh-LRG1 or PMA. (K) Representative macroscopic images and endpoint tumor weights demonstrating the rescue of LRG1-induced tumor progression by DNase I treatment in vivo.

Chen, Zhang, Xue et al 2026, Advanced Science · CC BY 4.0

PMID 42439413 · fig. FIGURE 3
4beta-PMA induces membrane ruffling and macropinocytosis in primary human neutrophils. (A) Representative flow cytometry gating strategy confirming isolation of a homogeneous CD66b+, Siglec-8- neutrophil population from healthy donors prior to functional assays. (B) Primary human neutrophils adhered to human aortic endothelial cell (HAEC) monolayers were treated with vehicle, 4beta-PMA (1 uM, 60 min), or 4beta-PMA and EIPA (25 uM, 30 min pretreatment), followed by visualization of membrane ruffle formation using scanning electron microscopy. The upper and lower panels in each column show representative images from independent fields acquired under the indicated experimental condition. Green arrows indicate membrane ruffles reflecting active cytoskeletal remodeling, whereas red arrows indicate cup-shaped macropinocytic structures representing nascent macropinosome formation. Scale bars, 2 um. (C) Quantification of membrane ruffling per cell under indicated conditions (n = 3). (D) Primary human neutrophils were incubated with FITC-dextran (70 kDa, 100 ug/mL) and stimulated with vehicle, 4beta-PMA, or 4beta-PMA and EIPA (n = 8). Dextran internalization was quantified by flow cytometry and expressed as fold change in mean fluorescence intensity (MFI). Representative histograms are shown. (E) Primary human neutrophils were treated with vehicle or 4beta-PMA in the presence or absence of cytochalasin D (2 uM, 30 min), followed by assessment of FITC-dextran uptake by flow cytometry (n = 5). Data are presented as means +/- SEM. Statistical significance was determined using one-way ANOVA with Tukey's multiple-comparisons test. ** p < 0.01; *** p < 0.001; **** p < 0.0001.

Addo, Babay, Sreekumar et al 2026, Antioxidants · CC BY 4.0

PMID 42510635 · fig. Figure 1
Tpsb2-CreERT2 enables efficient and specific labeling of mast cells, revealing their meningeal distribution. A) Minimal intensity projection of dural meninges stained with toluidine blue from mice at different developmental stages. n = 2-5 (mice). B) Quantification of (A). C) Targeting strategy of Tpsb2-CreERT2 mice. D) Representative contour plot of meningeal CD45+CD11b-CD3e-CD19- cells from Tpsb2-CreERT2; Ai14fl/+ mice. n = 3-4 (mice). E) Quantification of labeled immune cell subset in the meninges. n = 3-4 (mice). F) The percentage of mast cells in different tissues. n = 2-11 (mice). G) The number of meningeal mast cells from Tpsb2-CreERT2; Ai14fl/+ mice. n = 5-7 (mice). L) Maximal intensity projection of dural meninges stained for granule (green), mast cell (red, white), and nuclei (blue) from Tpsb2-CreERT2; Ai14fl/+ mice. n = 6 (mice). O) Maximal intensity projection of dural meninges stained for mast cells (red) and blood vessels (green) from Tpsb2-CreERT2; Ai14fl/+ mice. n = 3 (mice). Scale bar for all images, 2000 um (whole mount), 200 um (partial region). Data are presented as mean +/- SEM.

Li, Chen, Sun et al 2025, Advanced Science · CC BY 4.0

PMID 41195564 · fig. Figure 1
MG induces NET formation and immune activation in neutrophils. For NET visualization, neutrophils were pretreated with ATA (25 uM) before MG stimulation to inhibit MG-associated nuclease activity. (A) Representative Sytox Green staining of neutrophils stimulated with MG (80 MOI) (n = 3). Red arrows indicate NETs. (B) Representative scanning electron microscopy (SEM) images of NETs in MG-stimulated neutrophils (n = 3). Red arrows indicate NETs. (C) Representative confocal images of NETs induced by MG in neutrophils. Red arrows indicate NETs (n = 3). (D to F and K) Representative immunofluorescence images and quantification of neutrophil elastase (NE), citrullinated histone H3 (CitH3), and PAD3 fluorescence intensity in neutrophils after MG stimulation (n = 3). Red arrows in (D) and (E) indicate NETs; red arrows in (F) indicate nuclear translocation of PAD3. White dashed lines indicate enlarged regions. (G and J) Immunoblot analysis and quantification of CitH3, NE, and PAD3 protein levels (n = 6) in neutrophils after MG challenge. (H and I) Intracellular Ca 2+ fluorescence intensity and representative flow cytometry plots in neutrophils after MG stimulation (n = 3). (L) dsDNA levels in culture supernatants after micrococcal nuclease digestion (n = 6). (M) ELISA quantification of inflammatory cytokine levels in neutrophils from the indicated groups (n = 6). (N-O) Intracellular ROS fluorescence intensity and representative flow cytometry plots in neutrophils after MG stimulation (n = 3). Data are presented as means +/- SD from at least three independent experiments.

Wang, Liu, Gu et al 2026, Redox Biology · CC BY 4.0

PMID 42476007 · fig. Fig. 1
MG induces NET formation and immune activation in neutrophils. For NET visualization, neutrophils were pretreated with ATA (25 uM) before MG stimulation to inhibit MG-associated nuclease activity. (A) Representative Sytox Green staining of neutrophils stimulated with MG (80 MOI) (n = 3). Red arrows indicate NETs. (B) Representative scanning electron microscopy (SEM) images of NETs in MG-stimulated neutrophils (n = 3). Red arrows indicate NETs. (C) Representative confocal images of NETs induced by MG in neutrophils. Red arrows indicate NETs (n = 3). (D to F and K) Representative immunofluorescence images and quantification of neutrophil elastase (NE), citrullinated histone H3 (CitH3), and PAD3 fluorescence intensity in neutrophils after MG stimulation (n = 3). Red arrows in (D) and (E) indicate NETs; red arrows in (F) indicate nuclear translocation of PAD3. White dashed lines indicate enlarged regions. (G and J) Immunoblot analysis and quantification of CitH3, NE, and PAD3 protein levels (n = 6) in neutrophils after MG challenge. (H and I) Intracellular Ca2+ fluorescence intensity and representative flow cytometry plots in neutrophils after MG stimulation (n = 3). (L) dsDNA levels in culture supernatants after micrococcal nuclease digestion (n = 6). (M) ELISA quantification of inflammatory cytokine levels in neutrophils from the indicated groups (n = 6). (N-O) Intracellular ROS fluorescence intensity and representative flow cytometry plots in neutrophils after MG stimulation (n = 3). Data are presented as means +/- SD from at least three independent experiments. Different lowercase letters indicate significant differences among groups (P < 0.05).

Wang, Liu, Gu et al 2026, Redox Biology · CC BY 4.0

PMID 42476007 · fig. Fig. 1
CitH3 stage-dependently forms extended larger patches in advanced appendicitis. (A) Representative immunofluorescence image demonstrates CitH3 (green) in spatial association with extracellular DNA (propidium iodide; red) in inflamed appendiceal tissue. Insets show magnified views of the boxed regions and highlight nuclear [N] and extracellular DNA [E]. Scale bar: 100 um. (B) Quantification of CitH3 across catarrhal (Cat, n = 9), phlegmonous (Phl, n = 21), gangrenous (Gan, n = 11), and perforated/abscess appendicitis (P/A, n = 19). (C) Representative images of entire wall of vermiform appendix illustrating size-based segmentation of CitH3-positive patches in catarrhal (Cat) and gangrenous (Gan) appendicitis. Scale bar: 1 cm. (D) Quantification of CitH3 patches stratified by patch size. (E) Representative images of entire wall of vermiform appendix illustrating size-based segmentation of MPO-positive patches in catarrhal (Cat) and gangrenous (Gan) appendicitis. Scale bar: 1 cm. (F) Quantification of MPO across catarrhal (Cat, n = 9), phlegmonous (Phl, n = 21), gangrenous (Gan, n = 11), and perforated/abscess appendicitis (P/A, n = 19). (G) Quantification of MPO patches stratified by patch size.

Pachmann, Szep, Meyer zu Himmern et al 2026, Cells · CC BY 4.0

PMID 42645216 · fig. Figure 1
ZQG attenuates PMA-induced NETosis and inflammatory responses in human neutrophils via targeting the Nox4/ROS pathway. (A) ZQG suppresses oxidative burst and NET formation. Representative immunofluorescence images showing intracellular ROS (stained by DHE, red) and NETosis (marked by CitH3, green). Nuclei are counterstained with DAPI (blue). Scale bars: 20 um. (B) Quantitative analysis of intracellular ROS levels. (C) Quantification of NETosis, expressed as the percentage of Sytox Green+ cells. (D) Western blot analysis demonstrating the effects of ZQG and si-Nox4 on the protein expression of Nox4, p-Akt, and PADI4. (E) Densitometric quantification of Western blot results. (F) qPCR analysis of Nox4, PI3K, Akt, and PADI4 mRNA expression. (G) ELISA analysis of pro-inflammatory cytokine levels (IL-2, IL-5, IL-6, IL-12, TNF-alpha) in cell culture supernatants. Data are presented as mean ± SEM (n=10 independent experiments).

Fang, Deng, Li et al 2026, Frontiers in Immunology · CC BY 4.0

PMID 41684537 · fig. Figure 5
NETs formation in macrophage-neutrophil co-cultures is modulated by macrophage polarization state and environment. (A) Representative immunofluorescence images of M1 and M2 co-cultures; DAPI (blue), neutrophils (green), MPO (red), CD206 (grey). Scale bar, 50 um. (B) Kinetic NE activity in concurrently polarized and pre-polarized co-cultures. Mean fluorescence intensity (MFI) over time after IFN-gamma/LPS or IL-4/IL-13 stimulation, +/- neutrophils. (C) Representative live-cell imaging images of concurrently polarized M1/M2 macrophage co-culture. Neutrophils (red), cell-free DNA (green), Scale bar, 20 um at t0, t4 and t14 (h). Leica Mica, 20x magnification, 14h run, imaging: every 15 min at 37 degrees C, 5% CO2. (D) NETs quantification by flow cytometry (MPO+-Sytox Orange+ events) in M0, M1, and M2 co-cultures. (E) MPO-DNA ELISA. (F) NE-DNA ELISA. (G) Quantification of H3cit+ MPO+ Sytox Orange+ events in concurrently polarized (CP) and pre-polarized (PP) M0, M1, and M2 macrophage-neutrophil co-cultures by flow cytometry. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 (Mann-Whitney U test for comparisons between two groups and a Kruskal-Wallis test followed by Dunn's multiple comparisons test for comparisons of more than two groups). (A, B, E-G) n = 5 independent donors, (C) n = 1 donor, (D) n = 10 independent donors.

Blum, Jager, Jones et al 2026, Frontiers in Immunology · CC BY 4.0

PMID 42745859 · fig. Figure 4
Adoptive transfer of rTEM PMNs aggravates pulmonary injury. A,B) Generation of rTEM PMNs in vitro (A) and ICAM1 expression on normal PMNs or rTEM PMNs (B) (n = 3). C-E) MFI of CD11b, CD62L, and CXCR2 expression on normal PMNs or rTEM PMNs (n = 3). F) Schematic showing the administration of rTEM PMNs, intravital imaging and tissue harvest. G) Representative intravital imaging of Ly6G-labeled normal PMNs (red) or rTEM PMNs (red) and pulmonary microcirculation (FITC dextran, green). Quantification of PMN infiltration in lungs 3 h after PMN transfusion (two fields of view per mouse, n = 3). Scale bar, 20 um. H) Representative images of H&E-stained lung sections in mice and lung injury score 12 h after treatment (n = 5). Scale bar, 20 um. I) W/D ratio of lung tissues of mice with indicated intervention after 12 h (n = 5). J-N) qPCR analysis of Tnf-alpha, Il-6, Il-1beta, Kc, and Mip-2 in the lung of mice 12 h after PMN transfusion (n = 6). Statistics: unpaired two-tailed t-test in (A-E; G-N). Data are represented as mean +/- SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001.

Zi, Wu, Tang et al 2024, Advanced Science · CC BY 4.0

PMID 39119837 · fig. Figure 3
MG induces NET formation and immune activation in neutrophils. For NET visualization, neutrophils were pretreated with ATA (25 uM) before MG stimulation to inhibit MG-associated nuclease activity. (A) Representative Sytox Green staining of neutrophils stimulated with MG (80 MOI) (n = 3). Red arrows indicate NETs. (B) Representative scanning electron microscopy (SEM) images of NETs in MG-stimulated neutrophils (n = 3). Red arrows indicate NETs. (C) Representative confocal images of NETs induced by MG in neutrophils. Red arrows indicate NETs (n = 3). (D to F and K) Representative immunofluorescence images and quantification of neutrophil elastase (NE), citrullinated histone H3 (CitH3), and PAD3 fluorescence intensity in neutrophils after MG stimulation (n = 3). Red arrows in (D) and (E) indicate NETs; red arrows in (F) indicate nuclear translocation of PAD3. White dashed lines indicate enlarged regions. (G and J) Immunoblot analysis and quantification of CitH3, NE, and PAD3 protein levels (n = 6) in neutrophils after MG challenge. (H and I) Intracellular Ca2+ fluorescence intensity and representative flow cytometry plots in neutrophils after MG stimulation (n = 3). (L) dsDNA levels in culture supernatants after micrococcal nuclease digestion (n = 6). (M) ELISA quantification of inflammatory cytokine levels in neutrophils from the indicated groups (n = 6). (N-O) Intracellular ROS fluorescence intensity and representative flow cytometry plots in neutrophils after MG stimulation (n = 3). Data are presented as means +/- SD from at least three independent experiments. Different lowercase letters indicate significant differences among groups (P < 0.05).

Wang, Liu, Gu et al 2026, Redox Biology · CC BY 4.0

PMID 42476007 · fig. Fig. 1
RAD51 cross-links NET chromatin to maintain NET stability. (A) Transmission electron microscopy of NETs formed by human neutrophils isolated from the blood and stimulated with PMA for 4 hrs. (B) Single z-plane micrographs obtained by confocal fluorescence microscopy of human neutrophils activated with PMA at different stages of NETosis, stained for RAD51 (magenta), NE (yellow), MPO (cyan), and DNA (DAPI, blue). Arrows depict RAD51 translocated to the nucleus alongside NE. (C) Quantification of the fraction of RAD51 colocalizing with chromatin (DAPI) in individual human blood neutrophils at 90 min (N=6) and 150 min (N=5) post-PMA stimulation. (D) Electron microscopy of NET chromatin formed by human neutrophils stimulated with PMA in the presence of vehicle (DMSO) or RI-1. (E) Quantification of NET density in multiple electron micrographs as shown in (D). (G) Timelapse microscopy of degradation of NETs formed by human blood neutrophils in 3% human plasma treated with vehicle (DMSO) or RI-1. NETs were stained with Sytox Green and tracked every 5 min for 180 min post-NET formation. Scale bar: 50 um.

Tsansizi, Guan, Aramburu et al 2026, Science (New York, N.Y.) · CC BY 4.0

PMID 42623469 · fig. Figure 1
HMGB1+ EVs induce neutrophil activation through a RAGE-dependent pathway. Purified human neutrophils were either challenged with platelet-derived HMGB1+ EVs from the plasma of SSc patients (SSc HMGB1+ plt EVs), left untreated, or stimulated with the RAGE agonist glycated albumin, recombinant HMGB1, or HMGB1+ EVs from activated platelets (HMGB1+ plt EVs). Neutrophil activation was assessed by evaluating: membrane-bound MPO (mMPO, A ) (SSc EVs n = 14; untreated n = 12; glycated albumin n = 5; HMGB1 n = 6; HMGB1+ EVs n = 8); expression of the activation marker TIE2 ( B ) (SSc EVs n = 8; untreated n = 8; glycated albumin n = 7; HMGB1 n = 7; HMGB1+ EVs n = 7); extent of autophagy measured by Cyto-ID dye accumulation ( C ) (SSc EVs n = 14; untreated n = 11; glycated albumin n = 7; HMGB1 n = 7; HMGB1+ EVs n = 14); and NET generation quantified as MPO-DNA complexes in the supernatant ( D ) (SSc EVs n = 17; untreated n = 10; glycated albumin n = 5; HMGB1 n = 11; HMGB1+ EVs n = 5). E Neutrophils were either left untreated (top panel) or exposed to platelet-derived HMGB1+ EVs in the absence (middle panel) or presence (bottom panel) of a monoclonal antibody blocking RAGE. Cells were analyzed by confocal microscopy for autophagy (Cyto-ID dye, green), TIE2 (Alexa 647, blue), and citrullinated histone H4 (Alexa 546, red). DNA was counterstained with Hoechst (white).

Maugeri, Ramirez, Capobianco et al 2026, Cell Death & Disease · CC BY 4.0

PMID 41935037 · fig. Fig. 4
Intravital microscopy of postcapillary venules in the murine cremaster muscle 2 hours after intrascrotal TNF injection. Panels show neutrophil rolling velocities, slow-rolling flux, arrest and adhesion. Neutrophils (green, anti-Ly6G labeled) are visualized rolling and arresting along the endothelium. This captures the early steps of neutrophil extravasation: selectin-mediated rolling, followed by integrin-mediated arrest and firm adhesion. Mus musculus model.

Amini W 2025, JCI insight · CC BY 4.0

PMID 40493407 · fig. Figure 4
Chromatin externalization from neutrophils during NETosis (neutrophil extracellular trap formation). Immunofluorescence staining of human neutrophils stimulated with PMA showing: citrullinated histone H3 (Cit-H3, PAD4-mediated marker), MPO (myeloperoxidase, azurophilic granule marker), and DNA (Sytox Green/DAPI). NETs are visible as extracellular web-like structures. Unstimulated controls (PBS) show the typical multi-lobed nucleus morphology of mature neutrophils.

Singh J 2024, Cell communication and signaling : CCS · CC BY 4.0

PMID 39252008 · fig. Figure 1
Immunofluorescence staining of human neutrophils for DNA (DAPI, red) and nesprin-1 (green), a nuclear envelope spectrin repeat protein. The characteristic polymorphonuclear (segmented, multi-lobed) nucleus of human neutrophils is visible. Serial time points after PMA stimulation show progressive nuclear envelope rupture during NET formation. Resting neutrophils (0 min) show intact multi-lobed nuclei.

Singh J 2024, Cell communication and signaling : CCS · CC BY 4.0

PMID 39252008 · fig. Figure 2

Illustrations

Neutrophil, eosinophil, and basophil side by side, with nuclear shape and granule types labeled.

Granulo / granulo.site · CC0

Neutrophil granule populations: azurophilic, specific, gelatinase, and secretory vesicles, with their contents and the order they are released.

Granulo / granulo.site · CC0

PMID 21094463

NET formation: activation, oxidant burst, elastase and MPO entering the nucleus, PAD4 histone citrullination, chromatin release, and bacteria trapped.

Granulo / granulo.site · CC0

PMID 15001782
Transmission electron micrograph of an eosinophil showing ultrastructural signs of early ETosis, including a slightly irregular nuclear profile and altered granule distribution.

Caruso M et al. Cancers. 2025;17(19):3250. PMID: 41097776. · undefined

PMID 41097776
Transmission electron micrograph illustrating an advanced stage of eosinophil ETosis. Extracellular DNA traps appear as decondensed chromatin fibers decorated with granule proteins extending from the cell.

Caruso M et al. Cancers. 2025;17(19):3250. PMID: 41097776. · undefined

PMID 41097776
High-resolution confocal microscopy of neutrophils showing mitochondrial morphology differences in malaria-elicited versus sepsis-elicited neutrophils. Mitochondrial dynamics correlate with degranulation capacity.

Zakrzewski P et al. EMBO Mol Med. 2026. PMID: 42204305. · undefined

PMID 42204305
Tissue eosinophils undergoing ETosis in inflammatory sites, in proximity of intact eosinophils. Electron micrographs of biopsy samples from patients with eosinophil-associated diseases, showing EETosis (eosinophil extracellular trap cell death) in tissue.

Neves VH et al. Front Immunol. 2022;13:938691. PMID: 35874692. · CC BY 4.0

PMID 35874692 · fig. Fig. 3
Early ultrastructural signs of eosinophil ETosis (EETosis): a representative intact eosinophil with bilobed nucleus (N), specific granules (SG) with preserved crystalloid core (CC), and early ETosis showing irregular nuclear profile and altered granule distribution.

Neves VH et al. Front Immunol. 2022;13:938691. PMID: 35874692. · CC BY 4.0

PMID 35874692 · fig. Fig. 4
Band neutrophil (immature neutrophil with unsegmented nucleus) in a peripheral blood smear at 40x magnification.

Bobjgalindo, Wikimedia Commons, CC BY-SA 4.0. · CC BY-SA 4.0

source
Basophil surrounded by erythrocytes and platelets in a Wright-stained peripheral blood smear.

Echinaceapallida, Wikimedia Commons, CC BY-SA 4.0. · CC BY-SA 4.0

source
Basophil granulocyte in May-Grunwald-Giemsa stained blood smear; note the dark purple-black granules filling the cytoplasm.

Hanna Soerensson (Flickr/Wikimedia Commons), CC BY-SA 2.0. · CC BY-SA 2.0

source
Eosinophil in a Giemsa-stained peripheral blood smear, showing characteristic bilobed nucleus and pink-orange specific granules.

Dr Graham Beards, Wikimedia Commons, CC BY-SA 3.0. · CC BY-SA 3.0

source
Medical illustration of a neutrophil showing the multi-lobed nucleus and cytoplasm with granules.

BruceBlaus, Wikimedia Commons, CC BY 3.0. · CC BY 3.0

source