EMBO/soda-nel huggingface dataset:
Alarmin S100A9 restricts retroviral infection by limiting reverse transcription in human dendritic cells (2021)
Figure 10

Figure 10: Human S100A9 inhibits HIV-1 reverse transcriptase activity and uncoating.

Colorimetric HIV-1 RT activity assay was adapted from manufacturer's protocol using constant amount of HIV-1 RT (0.5ng) and increasing amounts of lysates from (A) E2C- and S100A9-expressing HEK293T and (B) E2C- and S100A9-expressing Jurkat cells. Means ± SD colorimetric data obtained from at least two independent experiments were normalized to E2C-expressing lysates and shown on graphs.

(C) Schematic description of fate-of-capsid assay is displayed above. HEK293T expressing E2C or S100A9 were transduced with HIV-Luc (10ng p24) for 4 h. Cells were then subjected to the fate of capsid assay (see methods) in order to pull-down intact cores (CA cores) (recovered in the pellet). Equal volumes from the soluble (top fraction) and pelleted (down fraction) materials were analyzed by western blotting in order to evaluate the presence of p24 (CA), CypA, S100A9 and E2C proteins.

When applicable, student t-test was performed to determine statistical significance (*P<0.1;**P<0.01;***P<0.001).
Alarmin S100A9 restricts retroviral infection by limiting reverse transcription in human dendritic cells (2021)
Figure 11

Figure 11: Human S100A9 inhibits HIV-1 reverse transcriptase activity in vitro in a divalent cation-dependent manner.

(A) Schematic description of E2C and S100A9 immunopurification and elution protocol (left panel) and western blot analyses of total extracts (input) and eluated immunopurified E2C and S100A9 (right panels).

(B) Colorimetric HIV-1 RT activity assay using constant amount of HIV-1 RT (0.5ng) and performed with increasing amounts of immunopurified E2C and S100A9 eluates. Means ± SD colorimetric data obtained from duplicates of depicted independent experiments were normalized to E2C-containing conditions and shown on graphs. Each datapoint in the graph represents an independent experiment.

(C) Colorimetric HIV-1 RTase activity was performed with 10µg of immunoprecipitated and eluted E2C or S100A9 in presence of increasing MgCl2 concentrations. Means ± SD colorimetric data obtained from at least three independent experiments were normalized to E2C-containing conditions and shown on graphs.

When applicable, student t-test was performed to determine statistical significance (*P<0.1;**P<0.01;***P<0.001).

EXPANDED VIEW FIGURE LEGENDS
ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth. (2016)
Figure 1

Figure 1. ROCK expression is elevated in pancreatic cancer and promotes disease progression.

A. ROCK2 immunohistochemistry stained sections of normal and stages I, II and III cases of human pancreas adenocarcinoma. Scale bar = 50 µm (left). Histoscores of ROCK2 staining (right) in normal pancreas (n=5), and pancreas adenocarcinoma stage I (n=22), stage II (n=46) and stage III/IV (n=4). One-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

B. Overall survival of 107 patients without alterations versus 37 patients with ROCK1 and/or ROCK2 gene amplification, significantly increased mRNA or truncation mutation from TCGA research network. Survival p value determined by Log-Rank test.

C, D. Log2 median-centered ROCK1 or ROCK2 RNA expression in normal (n=39) vs PDAC (n=39), normal (n=5) vs pancreatic adenocarcinoma (PAC) (n=12), or normal (n=6) vs pancreatic carcinoma (PC) (n=11) samples from indicated studies. Exact p values determined by Mann-Whitney test.

E. ROCK1 and ROCK2 mRNA expression in human PDAC (n=146) from the TCGA research network. Significance (p value) of slope deviation from 0 determined by Deming regression.

F. Representative hematoxylin and eosin (H&E) and ROCK2 immunohistochemistry stained sections of normal mouse pancreas, acinar-to-ductal metaplasia (ADM), pancreatic intraepithelial neoplasia (PanIN) stages 1-3, and PDAC from indicated genotype mice. Scale bar = 50 µm.

G. Quantification of ROCK2 staining in epithelial cells of normal, ADM/PanIN1 (KC), PanIN2 (KPC), PanIN3 (KPC) and PDAC (KPC) pancreatic tissue (n=5 mice per group). One-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

H. Survival analysis of Pdx1-Cre; LSL-KRasG12D/+; LSL-Trp53R172H/+; LSL-ROCK2:ER (RKPC) mice without (n=21) or with conditional ROCK activation with tamoxifen citrate (n=19). Survival p value determined by Log-Rank test.
ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth. (2016)
Figure 2

Figure 2. ROCK activation induces PDAC cell invasion.

A. H&E stained sections of cell invasion into collagen matrix after 8 days. Scale bar = 100 µm. Invasion index of KPC cells in the presence or absence of 10 µM H1152 ROCK inhibitor. Means ± SEM (n=9 for untreated, n=8 for H1152), p value by unpaired t test.

B. Schematic representation of ROCK domains (RBD, Rho binding domain; PH, pleckstrin homology domain; CR, cysteine-rich). Conditionally-activated human ROCK1, human ROCK2 and GFP control fusion proteins (EGFP, enhanced green fluorescent protein; hbER, estrogen receptor hormone binding domain) were expressed in KPflC mouse PDAC cells and blotted with anti-GFP antibody.

C. KPflC cells expressing GFP:ER, ROCK1:ER or ROCK2:ER fusion proteins were treated for 24 h with EtOH vehicle or 1 µM 4HT in the presence or absence of 1 µM or 10 µM H1152. Immunoblotting shows endogenous ROCK1 and ROCK2, ER-fusions, and phosphorylation of MLC2 (T18S19). Total MLC (MRCL3/MRLC2/MYL9) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were blotted as loading controls.

D. H&E stained sections of cell invasion into collagen matrix after 8 days. Scale bar = 100 µm. Invasion index of KPflC cells treated with 1 µM 4HT. Means ± SEM (n=6), one-way ANOVA with multiplicity adjusted exact p value by post hoc Dunnett’s multiple comparison test.

E. Cell proliferation determined by Ki67 immunofluorescence. Scale bar: 20 µm.

F. Quantification of cell number at the collagen matrix surface per 0.046 mm2 field. Means ± SEM (n=30), one-way ANOVA with multiplicity adjusted exact p value by post hoc Dunnett’s multiple comparison test.

G. Ki67 positive cell percentages at the surface and within the collagen matrix. Means ± SEM (n=30; n=12 for GFP:ER/Matrix), one-way ANOVA with multiplicity adjusted exact p value by post hoc Dunnett’s multiple comparison test.

H. Viable cell relative to starting cell numbers were determined after 24 h or 48 h treatment with vehicle (-) or 4HT on uncoated plastic surfaces. Means ± SEM (n=3).

I. Viable cell relative to starting cell numbers were determined after 24 h or 48 h treatment with vehicle (-) or 4HT on collagen1-coated surfaces. Means ± SEM (n=3).
ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth. (2016)
Figure 4

Figure 4. MMP induction by ROCK activation.

A. Volcano plots of RNA sequencing data of genes that pass a threshold false discovery rate (FDR) < 5%, with log10 fold-change (FC) in expression in 4HT treated ROCK1:ER expressing cells relative to GFP:ER expressing cells (left) or 4HT treated ROCK2:ER expressing cells relative to GFP:ER expressing cells (right) versus log10 adjusted p value (n=3). ROCK1:ER+4HT vs GFP:ER+4HT; 3828 genes. ROCK2:ER+4HT vs GFP:ER+4HT; 4481 genes.

B. Venn diagram of genes with FDR < 5% and > 2-fold expression changes for ROCK1:ER+4HT vs GFP:ER+4HT and ROCK2:ER+4HT vs GFP:ER+4HT.

C. Heatmap of 33 differentially expressed genes in the MetaCoreTM process network Cell adhesion: Cell-matrix interaction. High relative expression in red and low relative expression in blue.

D. MMP average RNA sequence reads. Mean ± SEM (n=3) * adjusted p-value <0.05.

E. Mmp10 mRNA levels relative to Gapdh determined by qPCR following treatment with EtOH vehicle (-) or 1 µM 4HT for 24 h (left). Means ± SEM (n=4), p value by unpaired t test. Mmp10 mRNA levels relative to Gapdh determined by qPCR following treatment with EtOH vehicle (-), 1 µM 4HT or 4HT + 1 µM H1152 ROCK inhibitor for 24 h (right). Means ± SEM (n=3), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

F. Mmp13 mRNA levels relative to Gapdh determined by qPCR following treatment with EtOH vehicle (-) or 1 µM 4HT for 24 h (left). Means ± SEM (n=4), p value by unpaired t test. Mmp13 mRNA levels relative to Gapdh determined by qPCR following treatment with EtOH vehicle (-), 1 µM 4HT or 4HT + 1 µM H1152 ROCK inhibitor for 24 h (right). Means ± SEM (n=3), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

G. MMP10 immunohistochemistry stained sections of human pancreas adenocarcinoma. Scale bar = 100 µm (left). Histoscores of MMP10 staining (right) in normal pancreas (n=5), and pancreas adenocarcinoma grade 1 (n=23), grade 2 (n=27) and grade 3 (n=13). One-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.
ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth. (2016)
Figure 5

Figure 5. MMP proteins are efficiently released in response to ROCK activation.

A. Confocal microscope images of ROCK1:ER-expressing cells co-stained for F-actin, MMP10 (left) or MMP13 (right) and DAPI following treatment with vehicle or 1 µM 4HT for 24 h. Multiple z-planes were used to generate x-z and y-z images. Scale bar = 5 µm.

B. Representative immunoblot of MMP13 and MMP10 in conditioned media, as well as MMP10 and GAPDH in cell lysates. Cells were treated with vehicle (-) or 1 µM 4HT for 48 h.

C. Representative stained gel of ultracentrifuge-enriched microvesicle protein from GFP:ER or ROCK1:ER-expressing cell-conditioned media following treatment with vehicle (-) or 1 µM 4HT for 24 h (top). Absolute arbitrary unit values for total microvesicle protein levels in stained gels (bottom). Means ± SEM (n=4), p value by ratio paired t-test.

D. Representative immunoblot of MMP10 and caveolin in ultracentrifuge-enriched microvesicle proteins from cell-conditioned media following treatment with vehicle (-) or 1 µM 4HT for 24 h as well as MMP10, caveolin and GAPDH in cell lysates (top left). Transmission electron microscopy of ultracentrifuge-enriched microvesicles (top center), and immunogold labeling of MMP10 in ROCK1:ER 4HT-treated microvesicles, indicated by red arrows (top right). Absolute arbitrary unit values for MMP10 levels in western blots of ultracentrifugation-enriched microvesicle proteins (bottom left). Means ± SEM (n=4), p value by ratio paired t test. Ratios of MMP10 to caveolin (bottom center) or to total microvesicle proteins (bottom right). Means ± SEM (n=4), p value by ratio paired t test.

E. Absolute arbitrary unit values for caveolin levels in western blots of ultracentrifugation-enriched microvesicle proteins. Means ± SEM (n=4), p value by ratio paired t test. Ratio of caveolin to total microvesicle proteins. Means ± SEM (n=4), p value by ratio paired t test.

F. Ratios of MMP10 to GAPDH and caveolin to GAPDH in western blots of whole cell lysates. Means ± SEM (n=3), p value by ratio paired t test.
ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth. (2016)
Figure 6

Figure 6. ROCK activation promotes collagen degradation.

A. Representative fluorescence images of cells treated with 1 µM 4HT in the absence or presence of 10 µM H1152 for 18 h on Collagen1-FITC (Col1-FITC). Co-staining for F-actin, MMP10 (red) and DAPI (blue). Scale bar = 10 µm.

B. Quantification of collagen degradation by cells treated with 1 µM 4HT or 4HT + 10 µM H1152 for 16 h. Means ± SEM (n=15), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

C. Quantification of collagen degradation by cells treated with 1 µM 4HT, 4HT + DMSO vehicle, 4HT + 50 µM Blebbistatin or 4HT + 10 µM GM6001 for 16 h. Means ± SEM (n=15), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

D. Immunofluorescence of collagen matrix sections co-stained for MMP10 and DAPI. Scale bar = 20 µm.

E. Mmp13 immunohistochemistry stained sections of collagen matrices. Scale bar = 50 µm.
ROCK signaling promotes collagen remodeling to facilitate invasive pancreatic ductal adenocarcinoma tumor cell growth. (2016)
Figure 7

Figure 7. ROCK activation promotes MMP-dependent invasive growth.

A. H&E stained sections of cell invasion into collagen matrix after 8 days, in the absence (top) or presence of 10 µM GM6001 (bottom). Scale bar = 100 µm.

B. Invasion index of KPflC cells. Means ± SEM (n=4), p value by unpaired t test.

C. Quantification of cell number at the collagen matrix surface per 0.046 mm2 field. Means ± SEM (n=20), p value by unpaired t test.

D. Cell proliferation determined by Ki67 immunofluorescence. Scale bar: 20 µm.

E. Ki67 positive cell percentages at the collagen matrix surface. Means ± SEM (n=20; n=19 for GFP:ER/vehicle, n=18 for GFP/GM6001), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

F. Ki67 positive cell percentages in collagen matrix. Means ± SEM (n=20; n=8 for GFP:ER/ vehicle, n=10 for GFP:ER/GM6001, n=17 for ROCK1:ER/GM6001, n=15 for ROCK2:ER/GM6001), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

G. The increase in viable cell numbers of cells plated on uncoated plastic surfaces and treated with 1 µM 4HT for 24 h was not affected by 10 µm GM6001. Means ± SEM (n=3), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.

H. The increase in viable cell numbers of cells plated on collagen1 (Col1) coated surfaces and treated with 1 µM 4HT for 24 h was not affected by 10 µM GM6001. Means ± SEM (n=3), one-way ANOVA with multiplicity adjusted exact p value by post hoc Tukey multiple comparison test.
Interferon-beta signaling in retinal mononuclear phagocytes attenuates pathological neovascularization (2016)
Figure 1

Figure 1. Loss of Ifnar1 signaling elicits inflammatory processes and angiogenesis in laser-induced retinal damage

A Experimental design. Laser coagulation was performed in C57BL6/J control and Ifnar1-/- mice. Animals were analyzed 3, 7 and 14 days after laser treatment.

B, C Representative Iba1 stainings of retinal flat mounts detecting microglia/macrophages in laser spots 3 days after laser coagulation in C57BL6/J controls (B) and Ifnar1-/- (C) mice. Scale bar: 20 µm.

D Quantification of amoeboid-shaped mononuclear phagocytes in laser spots. Values show mean ± SD. (n = 11-12 retinas; unpaired Student’s t-test: ***p = 0.0004).

E Quantification of immune cell morphology in laser spots using a grid image analysis system. Values show mean ± SD. (n = 42-62 cells; unpaired Student’s t-test: ***p < 0.0001).

F-K Representative fundus fluorescein angiography images of C57BL6/J (F-H) and Ifnar1-/- (I-K) mice 3, 7 and 14 days after laser-induced damage.

L Quantification of vascular leakage by analyzing pixel intensities at 3, 7 and 14 days after laser-induced retinal damage in C57BL6/J controls versus Ifnar1-/- mice. Values show mean ± SD. (n = 14-22 eyes; One-way ANOVA followed by Tukey’s post-test: ***p < 0.0001).

M-P Representative images of lectin stained choroidal flat mounts 7 and 14 days after laser coagulation in C57BL6/J control mice (M, N) and Ifnar1-/- animals (O, P). Dashed lines indicate CNV areas and the asterisk marks the central optic nerve head. Scale bar: 200 µm.

Q Quantification of lectin-stained CNV areas with ImageJ software. Bars show mean ± SD. (n = 4-11 RPE/choroidal flat mounts; One-way ANOVA followed by Tukey’s post-test: *p = 0.0281).
Interferon-beta signaling in retinal mononuclear phagocytes attenuates pathological neovascularization (2016)
Figure 2

Figure 2. IFN-β ameliorates microgliosis and inhibits choroidal neovascularization

A Experimental design. Laser coagulation was performed in all C57BL6/J mice that were either untreated or received 10,000 units IFN-b i.p. every second day until animals were analyzed 3, 7 and 14 days after laser treatment, respectively.

B, C Representative Iba1 stainings of retinal flat mounts detecting microglia/macrophages in laser spots 3 days after laser coagulation in control mice (B) or IFN-b treated animals (C).

Scale bar: 20 µm.

D Quantification of amoeboid-shaped mononuclear phagocytes in laser spots. Values show mean ± SD. (n = 7-10 retinas; unpaired Student’s t-test: ***p < 0.0001).

E Quantification of immune cell morphology in laser spots using a grid image analysis system. Values show mean ± SD. (n = 41-62 cells; unpaired Student’s t-test: ***p < 0.0001).

F-K Representative fundus fluorescein angiography images of control mice (F-H) or IFN-b treated animals (I-K) 3, 7 and 14 days after laser-induced damage.

L Quantification of vascular leakage by analyzing pixel intensities at 3, 7 and 14 days after laser-induced retinal damage in control mice and IFN-b treated animals. Values show mean ± SD. (n = 15-22 eyes; One-way ANOVA followed by Tukey’s post-test: ***p = 0.0004).

M-P Representative images of lectin stained choroidal flat mounts 7 and 14 days after laser coagulation in control mice (M, N) and IFN-b treated animals (O, P). Dashed lines indicate CNV areas and the asterisk marks the central optic nerve head. Scale bar: 200 µm

Q Quantification of lectin-stained CNV areas with ImageJ software. Bars show mean ± SD. (n = 7-12 RPE/choroidal flat mounts; One-way ANOVA followed by Tukey’s post-test: **p = 0.0038).
Interferon-beta signaling in retinal mononuclear phagocytes attenuates pathological neovascularization (2016)
Figure 3

Figure 3. Loss of Ifnar1 signaling in mononuclear phagocytes enhances CNV

A Experimental design. Laser coagulation was performed in tamoxifen-treated Cx3cr1CreER, Ifnar1fl/fl and Cx3cr1CreER:Ifnar1fl/fl mice. Animals were analyzed 3, 7 and 14 days after laser treatment.

B-D Representative Iba1 staining results of retinal flat mounts detecting microglia/macrophages in laser spot 3 days after laser coagulation in Cx3cr1CreER (B), Ifnar1fl/fl (C) and Cx3cr1CreER:Ifnar1fl/fl (D) mice. Scale bar: 20 µm.

E Quantification of amoeboid-shaped mononuclear phagocytes in laser spots. Values show mean ± SD. (n = 17-29 retinas; unpaired Student’s t-test: ***p = 0.0003, **p = 0.0044).

F Quantification of immune cell morphology in laser spots using a grid image analysis system. Values show mean ± SD. (n = 44-52 cells; unpaired Student’s t-test: ***p < 0.0001).

G-O Representative fundus fluorescein angiography images of Cx3cr1CreER (G-I), Ifnar1fl/fl (J-L) and Cx3cr1CreER:Ifnar1fl/fl (M-O) mice 3, 7 and 14 days after laser-induced damage.

P Quantification of vascular leakage by analyzing pixel intensities at 3, 7 and 14 days after laser-induced retinal damage in Cx3cr1CreER, Ifnar1fl/fl and Cx3cr1CreER:Ifnar1fl/fl mice. Values show mean ± SD. (n = 5-12 eyes; One-way ANOVA followed by Tukey’s post-test: **p = 0.0032, *p = 0.0247).

Q-V Representative images of lectin stained choroidal flat mounts 7 and 14 days after laser coagulation in Cx3cr1CreER (Q, R), Ifnar1fl/fl (S, T) and Cx3cr1CreER:Ifnar1fl/fl (U, V) mice. Dashed lines indicate CNV areas and the asterisk marks the central optic nerve head. Scale bar: 200 µm.

W Quantification of lectin-stained CNV areas with ImageJ software. Bars show mean ± SD. (n = 4-11 RPE/choroidal flat mounts; One-way ANOVA followed by Tukey’s post-test: *p = 0.043, ***p = 0.0007).
SPINK6 inhibits human airway serine proteases and restricts influenza virus activation (2021)
Figure 1

Figure 1. SPINK6 constrains proteolytic activity of trypsin, and trypsin-mediated HA cleavage and viral growth. (A) TPCK-trypsin is premixed with wtSPINK6 protein or mutSPINK6 protein or PBS in triplicate, incubated with a fluorogenic substrate for 30 min, and then applied to fluorescence assay. Data are presented as mean and SD in a representative experiment performed 3 times. The fluorescence intensity of TPCK-trypsin/PBS mixture is arbitrarily set as 1. ***, P<0.001. (B) At 48h post-transfection of wtSPINK6 plasmid in 293T cells, cell lysate and concentrated supernatant (50×) were applied to the detection of SPINK6 protein and β-actin by WB. (C) At 48h after co-transfection of H7 plasmid with wtSPINK6 plasmid or blank vector, the transfectants were incubated with or without TPCK-trypsin for 30 min, and then applied to examine HA cleavage by WB. Intensities of HA2 and HA0 bands are quantified with ImageJ. HA2/HA0 ratio of each sample is shown at the bottom. (D) At 48h after transfection of H7 plasmid, the transfectants were incubated with TPCK-trypsin in the presence of recombinant wtSPINK6 protein or PBS or a protease inhibitor AEBSF for 30 min and then applied to examine HA cleavage. (E) At 24h after transfection of wtSPINK6 plasmid or blank vector in triplicate, A549 cells were inoculated with H7N9/ah virus. At the indicated hours post infection (hpi), culture media (supernatant) and cell lysate were harvested for viral load detection. Data are presented as mean and SD in a representative experiment performed 3 times. **, P<0.01; ***, P<0.001. Student's t test.
SPINK6 inhibits human airway serine proteases and restricts influenza virus activation (2021)
Figure 2

Figure 2. SPINK6 inhibits HAT and KLK5, and HAT- and KLK5- mediated HA cleavage.

(A) At 48 hours post transfection of the indicated protease plasmids in triplicate, BHK21 cells were incubated with a fluorogenic substrate and wtSPINK6 or loss-of-function mutSPINK6 or PBS for 2 hours and then applied to fluorescence assay. Data represent mean and SD of triplicated wells in a representative experiment performed 3 times. **, P<0.01. Student's t test. (B) At 48h after co-transfection of the indicated protease plasmids and H7 or H1 plasmid, BHK21 cells were lysed to examine HA cleavage with WB. (C) At 48h after triple-transfection of H7, the indicated proteases and wtSPINK6 or vector, BHK21 cells were lysed for the detection of HA cleavage. (D) At 48h after triple-transfection of H7, HAT or TMPRSS2, wtSPINK6 or mutSPINK6, BHK21 cells were lysed for the detection of HA cleavage. (E) At 48h after triple-transfection of H1, the indicated proteases and wtSPINK6 or mutSPINK6, BHK21 cells were lysed for the detection of HA cleavage.
SPINK6 inhibits human airway serine proteases and restricts influenza virus activation (2021)
Figure 3

Figure 3. SPINK6 inhibits virus growth and maturation mediated HAT and KLK5.

(A) At 36h after transfection of the indicted protease and wtSPINK6 plasmids or blank vector in triplicate, BHK21 cells were inoculated with H7N9/ah at a MOI of 0.5. Cell-free culture media were harvested at 24 hpi for viral titration. Data represent the mean and SD of the triplicated wells in a representative experiment performed 3 times. **, P<0.01. Student's t test. (B) At 24h after transfection of HAT or KLK5 plasmid in sextuplicate, A549 cells were inoculated with H1N1/pdm at MOI of 0.25. The infected cells were incubated with recombinant wtSPINK6 or mutSPINK6 protein in triplicate for 24h. Culture media in each well were stored in two aliquots, one was applied to viral titration with conventional plaque assay (black bars), the other was pre-treated with TPCK-trypsin for 1 hour prior to plaque assay (grey bars). Data represent the mean and SD of the triplicated wells in a representative experiment performed 3 times. *, P<0.05; **, P<0.01; ***, P<0.001. Student's t test.