Journal: Pathogens

Article Title: Echinococcus multilocularis Calreticulin Inhibits Lectin Pathway of Complement Activation by Directly Binding to Mannose-Binding Lectin

doi: 10.3390/pathogens14040354

Figure Lengend Snippet: Inhibition of C3b and C4b deposition by r Em CRT and its functional binding regions measured by ELISA. ( A ) Pre-incubation of 100 μL C1qD (1:50) as source of natural MBL with different amounts of r Em CRT, r Em CRT-S, or r Em CRT-NP (0, 2, 4 μM) before adding into mannan-coated plates (50 μg/mL). After being washed, C1qD (1:150) was added as source of complement components to initiate lectin pathway of complement activation. Deposition of C3b ( a ) and C4b ( b ) was detected with anti-C3 or C4 monoclonal antibodies. ( B ) The similar ELISA procedure was performed using NHS as source of physiological MBL instead of C1qD serum to detect the generation of C3b (a) and C4b (b). Data are expressed as mean of OD 450 ± SDs of three independent experiments (* p < 0.005, ** p < 0.001, *** p < 0.0005, ns, no significant difference compared to plates without added r Em CRT).

Article Snippet: After washing with 1 × TBST containing 5 mM CaCl 2 , the C1qD diluted at 1:150 in 1 × Veronal Buffer (VB, Lonza, Basel, Switzerland) containing 0.1% gelatin, 0.05% Tween-20 was added (100 μL) as supplement of other complement components (without C1q) into each well of the plates and incubated at 37 °C for 1 h. The lectin pathway-activated C3b/C4b deposition was detected with rabbit anti-C3b monoclonal antibody (1:1000, BOSTER Biological Technology, Wuhan, China) and goat anti-C4b polyclonal antibody (1:3000, Abcam, Cambridge, UK).

Techniques: Inhibition, Functional Assay, Binding Assay, Enzyme-linked Immunosorbent Assay, Incubation, Activation Assay, Bioprocessing

Journal: Frontiers in Immunology

Article Title: Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices

doi: 10.3389/fimmu.2021.777932

Figure Lengend Snippet: Microfluidic devices for measuring neutrophil chemotaxis, phagocytosis, and swarming behaviors. (A) Microscopic image of a segment of the chemotaxis microfluidic device (x10 Brightfield, Nikon TiE) showing neutrophil chemotaxis towards C5a and C3a during increasing mechanical restriction. Each chemoattractant chamber is connected to the cell loading channel through 3 tapered channels. (B) Microscopic image of a segment of the phagocytosis microfluidic device (x10 Brightfield/Fluorescent, Nikon TiE) showing neutrophils (blue nuclei) from the outer chamber migrating towards the central reservoir through a migration channel to phagocytose S. aureus particles (green) in plasma at T 20 minutes. (C) Microscopic images obtained at three different time points (T 0 , T 10 , and T 30 minutes) showing the formation of a neutrophil swarm (blue nuclei) over a cluster of Texas red-labeled zymosan A S. cerevisiae bioparticles (Red).

Article Snippet: The chemoattractant chambers were filled either with fMLP (N-formyl-methionyl-leucyl-phenylalanine, 100 nM, Millipore Sigma), recombinant human C5a protein (ab61918, 0.1 - 10 μM, Abcam), or C3a (3677-C3-025, 0.1 - 10 μM, R&D Systems) diluted in HBSS with 0.5% BSA during the initial priming step.

Techniques: Chemotaxis Assay, Migration, Clinical Proteomics, Labeling

Journal: Frontiers in Immunology

Article Title: Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices

doi: 10.3389/fimmu.2021.777932

Figure Lengend Snippet: Chemotaxis of isolated neutrophils towards C5a and C3a and the effect of AVA on chemotaxis. (A) The percentage of neutrophils migrating directionally towards increasing concentrations of C5a and C3a compared to media alone (HBSS with 0.5%BSA, N=3, ****p < 0.0001; One-way ANOVA with Dunnett’s test) (B) C3a inhibits neutrophil chemotaxis towards C5a, C5a effect is dependent on concentration, and there is no interaction effect between C3 and C5a. (N=3 donors, p < 0.005, Repeated measures, two way ANOVA, with Sidak’s correction for multiple comparisons). (C) Percentage of neutrophils migrating directionally towards C5a (100 nM) after treatment of neutrophils with C5aR1 antagonist AVA (N=3, 4 or 5, each dot on the plot represents one experiment, ****p < 0.01 for comparisons to C5a control; ns represents not statistical significant. One way ANOVA with Dunnett’s multiple comparison test with single pooled variance).

Article Snippet: The chemoattractant chambers were filled either with fMLP (N-formyl-methionyl-leucyl-phenylalanine, 100 nM, Millipore Sigma), recombinant human C5a protein (ab61918, 0.1 - 10 μM, Abcam), or C3a (3677-C3-025, 0.1 - 10 μM, R&D Systems) diluted in HBSS with 0.5% BSA during the initial priming step.

Techniques: Chemotaxis Assay, Isolation, Concentration Assay, Control, Comparison

Journal: Frontiers in Immunology

Article Title: Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices

doi: 10.3389/fimmu.2021.777932

Figure Lengend Snippet: Atypical membrane elasticity of neutrophils and migration patterns when exposed to high C5a dose. (A) Percentage of neutrophil migration patterns during chemotaxis towards C5a, C3a, and fMLP. (N=3). (B) Microscopic images of elongated neutrophils when exposed to C5a 1µM inside the end chambers. Scale = 100 µm. (C) Percentages of unique reversed migration phenotype of neutrophils observed when exposed to high C5a concentration. (N=3, *p < 0.05; ns represents not statistical significant. One-way ANOVA with Dunnett’s test).

Article Snippet: The chemoattractant chambers were filled either with fMLP (N-formyl-methionyl-leucyl-phenylalanine, 100 nM, Millipore Sigma), recombinant human C5a protein (ab61918, 0.1 - 10 μM, Abcam), or C3a (3677-C3-025, 0.1 - 10 μM, R&D Systems) diluted in HBSS with 0.5% BSA during the initial priming step.

Techniques: Membrane, Migration, Chemotaxis Assay, Concentration Assay

Journal: Frontiers in Immunology

Article Title: Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices

doi: 10.3389/fimmu.2021.777932

Figure Lengend Snippet: Effect of C5 complement inhibitors on neutrophil chemotaxis towards endogenous complement activation with CVF. (A) Effect of AVA (250 nM) on endogenous complement activation by increasing CVF doses (N=3 donors, *p < 0.05, **p < 0.01; paired two-tailed t -test). (B) Effect of C5 inhibition with ECU (3 µM) and RA101295 (3 µM) on endogenous complement activation by CVF (N=3, **p < 0.01; ns represents not statistical significant. One-way ANOVA with Dunnett’s test).

Article Snippet: The chemoattractant chambers were filled either with fMLP (N-formyl-methionyl-leucyl-phenylalanine, 100 nM, Millipore Sigma), recombinant human C5a protein (ab61918, 0.1 - 10 μM, Abcam), or C3a (3677-C3-025, 0.1 - 10 μM, R&D Systems) diluted in HBSS with 0.5% BSA during the initial priming step.

Techniques: Chemotaxis Assay, Activation Assay, Two Tailed Test, Inhibition

Journal: Frontiers in Immunology

Article Title: Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices

doi: 10.3389/fimmu.2021.777932

Figure Lengend Snippet: Schematic representation of complement activation pathways, terminal inhibition strategies, and their effects on neutrophil functional behaviors. The classical, lectin, and alternative pathways converge on the cleavage of the central components C3 into C3a and C3b peptides. C3a acts as an anti-inflammatory mediator towards neutrophils, while C3b enhances phagocytosis through opsonization and forms C5 convertases, which cleaves C5 into C5a and C5b. C5a is a potent pro-inflammatory mediator and chemoattractant, while C5b forms the membrane attack complex (MAC), leading to cell and bacteria lysis. ECU and RA101295 are C5-inhibitors, which block the production of C5a and C5b peptides, while AVA blocks C5a mediated chemotaxis and pro-inflammatory effects.

Article Snippet: The chemoattractant chambers were filled either with fMLP (N-formyl-methionyl-leucyl-phenylalanine, 100 nM, Millipore Sigma), recombinant human C5a protein (ab61918, 0.1 - 10 μM, Abcam), or C3a (3677-C3-025, 0.1 - 10 μM, R&D Systems) diluted in HBSS with 0.5% BSA during the initial priming step.

Techniques: Activation Assay, Inhibition, Functional Assay, Membrane, Bacteria, Lysis, Blocking Assay, Chemotaxis Assay

Journal: Theranostics

Article Title: C5aR1 is a master regulator in Colorectal Tumorigenesis via Immune modulation

doi: 10.7150/thno.45058

Figure Lengend Snippet: The strong correlation between complement activation and CRC. ( A-D ) The associations between the mRNA levels of C3 (A), C5 (B), C5AR1 (C), and C5AR2 (D) and the overall survival of CRC patients (n=364). ( E, F ) The effect of C3 , C5 , C5ar1 or C5ar2 deficiency on AOM/DSS-induced colorectal tumorigenesis compared to WT control. Images of the colorectum, where CRC often developed at distal (rectum) sites (E), and quantitative analysis of tumor number and mass (F). The experiment was duplicated. Scale bar in (E), 1 cm. ( G ) Pathological analysis of control or tumor tissues, including H&E, Ki-67 and C3d staining. Scale bar, 100 µm for H&E and 50 µm for IHC. ( H ) C5a concentration in colon tissue homogenates (CTHs) measured by ELISA. n≥ 7 in each group of WT, C3 -KO, C5 -KO, C5ar1 -KO, or C5ar2 -KO mice. Data are represented as mean ± SEM; ns, not significant; * P <0.05; and *** P <0.001. NC, negative control.

Article Snippet: Then, mouse colon sections were incubated with an affinity purified pAb specific for mouse complement component C3d (1:80; R&D Systems, Minneapolis, MN), rabbit anti-Ki67 antibody (1 μg/ml; Abcam, Cambridge, MA) or rabbit anti-CD8 alpha antibody (1:1500; Abcam, Cambridge, MA) at 4°C overnight.

Techniques: Activation Assay, Control, Staining, Concentration Assay, Enzyme-linked Immunosorbent Assay, Negative Control

Journal: PLoS ONE

Article Title: Inhibition of C3 Convertase Activity by Hepatitis C Virus as an Additional Lesion in the Regulation of Complement Components

doi: 10.1371/journal.pone.0101422

Figure Lengend Snippet: (A) Comparison of serum C3 convertase level in randomly chosen HCV infected patient sera (n = 12) and normal human sera (NHS) from healthy donors (n = 12) using a commercially available ELISA kit. (B) HCV infected patient sera (n = 12) and NHS (n = 12) were subjected to analysis for comparison of C3b deposition on E. coli surface in the presence or absence of purified C3 protein. Asterisks denote: *p<0.05; **p<0.01; ***p<0.001 when compared to control. (C) Complement mediated lysis was inhibited in HCV infected patient sera. Normal sera (n = 6) and HCV infected patient sera (n = 6) were incubated with sheep RBC after treatment with EDTA. Sera from each test group were studied, with lysis of erythrocytes completed using EDTA treated guinea pig serum. (D) Sheep RBCs were incubated with sera in the presence or absence of anti-factor B antibody to separate out alternate pathway mediated lysis from classical antibody mediated lysis, and lysis was carried out as described above.

Article Snippet: Mouse monoclonal antibody to human C3 (Abcam, MA), goat anti-mouse secondary antibody (Sigma, MO), purified human complement component C3 protein (Quidel, CA) were purchased.

Techniques: Comparison, Infection, Enzyme-linked Immunosorbent Assay, Purification, Control, Lysis, Incubation