mouse complement c3  (MedChemExpress)

Journal: Bioactive Materials

Article Title: Splenic dendritic cell-targeting mRNA transfection of H-type ionizable lipid-based LNPs for enhancing tumor immunotherapy

doi: 10.1016/j.bioactmat.2026.02.018

Figure Lengend Snippet: Schematic illustration of in vivo tumor immunotherapy enhanced by mRNA/HNPs through intravenous injection. H18 lipid, DOPE, cholesterol, DMG-PEG 2000 and mRNA were mixed to form mRNA/H 18 NPs with the special multilamellar concentric nanostructures. Following intravenous administration, mRNA/H 18 NPs demonstrated preferential adsorption of complement C3 proteins to form a characteristic protein corona, resulting in specific mRNA transfection in the spleen, especially in splenic dendritic cells. When encapsulating tumor antigen-encoding mRNA, the mRNA/H 18 NPs achieved precise transfection of the antigen mRNA in splenic dendritic cells. This targeted delivery stimulated dendritic cell maturation and subsequent antigen presentation, initiating robust T cell priming. The activated antigen-specific cytotoxic T lymphocytes then infiltrated into tumor tissues, ultimately inducing tumor cell elimination.

Article Snippet: Mouse Complement C3 was purchased from MedChemExpress.

Techniques: In Vivo, Injection, Adsorption, Transfection, Immunopeptidomics

Journal: Bioactive Materials

Article Title: Splenic dendritic cell-targeting mRNA transfection of H-type ionizable lipid-based LNPs for enhancing tumor immunotherapy

doi: 10.1016/j.bioactmat.2026.02.018

Figure Lengend Snippet: In vivo splenic DC-specific transfection of mRNA/H 18 NPs and in vitro protein corona analysis of mRNA/H 18 NPs. (A) EGFP protein expression in splenic cell subsets of C57BL/6J mice 24 h post intravenous injection of different formulations. (B) The top 5 most abundant plasma proteins adsorbed on mRNA/H 18 NPs (C3: Complement C3; Ighm: Immunoglobulin heavy constant mu; Hbat1: Alpha-globin; Itih4: Inter alpha-trypsin inhibitor, heavy chain 4; Cnn2: Calponin). (C) Heatmap plot of major proteins in the protein corona adsorbed on mRNA/MC3-LNPs and mRNA/H 18 NPs. PBS group was used as a negative control. (D) Quantification of major adsorbed protein categories of different formulations. (E) Complement C3 abundance in protein corona adsorbed on mRNA/MC3-LNPs and mRNA/H 18 NPs. (F) Bioluminescence images of major organs and (G) Quantification of total bioluminescence flux in the spleen from C57BL/6J mice 6 h after intravenous injection of mLuc/H 18 NPs (mLuc dose of 0.25 mg kg −1 ). Mice were pre-treated with cobra venom factor (CVF) or PBS. (H) Fluorescence quantification of Cy5 mRNA delivered by uncoated or complement C3-coated Cy5-mRNA/H 18 NPs in BMDCs. BMDCs were pre-incubated with anti-CD11b (CR3) or anti-IgG blocking antibody. (I) Bioluminescence intensity of luciferase protein translated from mRNA delivered by uncoated or complement C3-coated mLuc/H 18 NPs in BMDCs. BMDCs were pre-incubated with anti-CD11b (CR3) or anti-IgG blocking antibody. Data were shown as mean ± SD (n = 3).

Article Snippet: Mouse Complement C3 was purchased from MedChemExpress.

Techniques: In Vivo, Transfection, In Vitro, Expressing, Injection, Clinical Proteomics, Negative Control, Combined Bisulfite Restriction Analysis Assay, Fluorescence, Incubation, Blocking Assay, Luciferase

Journal: bioRxiv

Article Title: Plasma Ficolins Enable Liver Macrophages to Capture Blood-Borne Bacteria by Recognizing Capsular Polysaccharides

doi: 10.64898/2025.12.22.696098

Figure Lengend Snippet: The requirement of the complement system for Ficolin-A-based immunity. A. The contribution of C3 to hepatic clearance of Spn-19F . Bacteria in the blood (left) and liver/spleen (right) of C3 -/- mice were quantified post i.v. infection with 10 6 (left) or 10 7 CFU (right). n = 3. B. The role of C3 receptors to hepatic clearance of Spn-19F . CRIg -/- , CR3 -/- and CRIg / CR3 -/- mice were infected with 10 6 (left) or 10 7 CFU (right) to quantify bacteria as in (A). n = 3. C. The role of the lectin pathway in hepatic clearance of Spn-19F . Masp1 -/- and Masp2 -/- mice were infected with 10 6 (left) or 10 7 CFU (right) to quantify bacteria as in (A). n = 3. D. Visualization of bacterial capture by KCs of complement-deficient mice. The liver sinusoids of C3 -/- , CRIg / CR3 -/- and Masp2 -/- mice were imaged by intravital microscopy as in 2D. n = 2. E. Complement-dependent bacterial capture by KCs in vitro . Primary mouse KCs were incubated with Spn- 19F in the presence of 10% serum for 30 min. Spn- 14 was used as a negative control. KC-bound bacteria are presented as the percentage of total bacteria. MOI = 1; n = 3-6. F. The importance of the complement system in the protection against Spn- 19F. Various complement-deficient mice were i.v. infected with 10 6 CFU of Spn- 19F and the survival is presented. n = 5. G. The model for the FCN-A-triggered complement-dependent and -independent pathways for bacterial capture by liver macrophages. FCN-A activates C3 on bacterial surface upon binding to the capsule through the lectin pathway. The representative data are presented as mean ± SD, and the statistical differences were determined by Two-way ANOVA with Tukey’s multiple comparisons test (A-C), multiple t tests (D and E) and log-rank test (F). **, P < 0.01; ****, P < 0.0001; ns, no significant difference.

Article Snippet: The C3 deposition on CPSs was detected using a 1:2000 dilution of HRP-conjugated goat IgG antibody against mouse complement C3 (MP Biomedicals) after incubation at 37°C for various durations.

Techniques: Bacteria, Infection, Intravital Microscopy, In Vitro, Incubation, Negative Control, Binding Assay

Journal: bioRxiv

Article Title: Loss of Complement Factor D suppresses alternative pathway activation but fails to reduce lipofuscin accumulation in the retinal pigmented epithelium of Abca4 -/- mice

doi: 10.1101/2025.10.25.684461

Figure Lengend Snippet: Immunofluorescence labeling of PFA-fixed wild type and C3 -/- mouse eyecup tissue with A) anti-C3 (MP Biomedicals, 55463) and B) anti-C3d (R&D Systems, AF2655) antibodies, showing genuine antibody labeling in the RPE of wild type samples, localized primarily to the basal side of the RPE. Note suspected non- specific binding of the anti-C3 primary antibody to photoreceptor outer segments (OS). Abca4 -/- samples were included as a no primary control, to show general tissue AF. Labeling using the anti-C3 antibody was performed using frozen sections and labeling using the anti-C3d antibody was performed using paraffin-embedded tissue sections. General tissue AF at 488 nm was included to assist in identifying eyecup structures and for comparison to immunofluorescence signal in the no primary control conditions. Note that each C3 antibody may detect multiple C3 fragments. The scale bar represents 10 µm and is consistent across all images. Choroid, RPE and OS are shown. Arrowheads show red blood cells, which are fluorescent at 488 nm in paraffin sections. Arrows show the location of suspected RPE basal labyrinth.

Article Snippet: C3 labeling was quantified in mouse eyecup structures, such as the RPE and choroid, using antibodies generated against full-length mouse C3 protein (referred to as “anti-C3”, MP Biomedicals) or purified mouse C3d (referred to as “anti-C3d”, R&D Systems) ( ).

Techniques: Immunofluorescence, Labeling, Antibody Labeling, Binding Assay, Control, Comparison

Journal: bioRxiv

Article Title: Loss of Complement Factor D suppresses alternative pathway activation but fails to reduce lipofuscin accumulation in the retinal pigmented epithelium of Abca4 -/- mice

doi: 10.1101/2025.10.25.684461

Figure Lengend Snippet: A) Representative images showing immunofluorescence labelling in PFA-fixed wild type, Abca4 -/- , Cfd -/- and Abca4 -/- ; Cfd -/- mouse eyecup tissue sections, using anti-C3 (MP Biomedicals) and anti-C3d (R&D Systems) antibodies. Anti-C3 immunofluorescence was performed using 6-12-mo frozen sections and anti-C3d immunofluorescence was performed using 12-mo paraffin embedded sections. For each image, 488 nm AF (green) and C3 immunofluorescence (magenta) are shown together, to aid in localizing the immunofluorescence signal. C3 immunofluorescence is also shown on its own in greyscale. Choroid, RPE and photoreceptor outer segments (OS) are labelled, with dotted lines indicating the basal (top) and apical (bottom) boundaries of the RPE. Arrowheads show the location of Bruch’s membrane, between the RPE basal labyrinth and the choroid region. Scale bar represents 10 µm. B-C) Quantification of total RPE immunofluorescence signal in each genotype using the anti-C3 and anti-C3d antibodies, respectively. Total immunofluorescence was quantified by measuring the mean immunofluorescence signal in the RPE of 3-4 images minus the fluorescent signal in 3-4 no primary antibody control images, per mouse. Each data point represents one mouse. Mean +/- 95% C.I. are shown. Data were analyzed by 1-way ANOVA with Tukey’s multiple comparisons test. **** indicates p<=0.0001

Article Snippet: C3 labeling was quantified in mouse eyecup structures, such as the RPE and choroid, using antibodies generated against full-length mouse C3 protein (referred to as “anti-C3”, MP Biomedicals) or purified mouse C3d (referred to as “anti-C3d”, R&D Systems) ( ).

Techniques: Immunofluorescence, Membrane, Control

Journal: bioRxiv

Article Title: Loss of Complement Factor D suppresses alternative pathway activation but fails to reduce lipofuscin accumulation in the retinal pigmented epithelium of Abca4 -/- mice

doi: 10.1101/2025.10.25.684461

Figure Lengend Snippet: A) Schematic representation of production and breakdown of the C3 protein. Estimated fragment molecular weights under reducing conditions are shown. Western blot was performed using eyecup lysate (RPE, choroid, sclera) detected using an antibody made against the C3d region (anti-C3d). Yellow shows the C3d region of the protein, which is part of the C3 α-chain (C3α). Note that the C3d region of the C3 protein contains the thioester site, which participates in covalent binding to target molecules (yellow arrowheads), potentially affecting fragment molecular weight of the C3b, iC3b, C3dg and C3d α-chain. B) Qualitative western blot images showing labelling of wild type and C3 -/- eyecup tissue using the anti-C3d antibody. Marked regions i-vi indicate C3 fragments of interest and are shown zoomed-in in greyscale in panel (C) with predicted C3 fragment identities indicated.

Article Snippet: C3 labeling was quantified in mouse eyecup structures, such as the RPE and choroid, using antibodies generated against full-length mouse C3 protein (referred to as “anti-C3”, MP Biomedicals) or purified mouse C3d (referred to as “anti-C3d”, R&D Systems) ( ).

Techniques: Western Blot, Binding Assay, Molecular Weight

Journal: bioRxiv

Article Title: Loss of Complement Factor D suppresses alternative pathway activation but fails to reduce lipofuscin accumulation in the retinal pigmented epithelium of Abca4 -/- mice

doi: 10.1101/2025.10.25.684461

Figure Lengend Snippet: A) Representative blots labelled with the anti-C3d antibody, showing all genotypes. Note the faint C3 α-chain fragment detected with the anti-C3d antibody, which may be the opsonized iC3b α62 fragment (ops iC3b) and was frequently detected in Cfd +/+ but not Cfd -/- conditions. Arrowhead (*) indicates the suspected opsonized C3b α-chain fragment selected for quantification. Higher molecular weight opsonized C3bα fragments were not quantified due to transfer inconsistencies and blot damage, which frequently affected the high molecular weight region of the blots. Rpe65 and β-actin were included as loading controls. B) Quantification of various C3 fragments under reducing conditions from mouse eyecup lysate, detected by the anti-C3d antibody. Animals used in this experiment range from 6-12 months of age. Relative quantities of C3 preprotein, C3α, iC3(H2O) α72, opsonized C3bα (*), iC3b α62 and C3dg were normalized to Rpe65 and β-actin, which were shown to have stable signal across the experimental conditions of interest (Supplementary Figure 6). Given the large number of experimental conditions, samples were run across multiple blots with a mix of genotypes per blot. To control for variability between blots, normalized C3 fragment quantities were expressed relative to the C3α fragment from WT samples. Note that quantities of C3α and iC3(H2O) α72 (filled circles) are represented on the left y-axis, and quantities of the preprotein, opsonized C3bα, iC3b α62 and C3dg fragments (empty circles) are represented on the right y-axis. Data were analyzed using a two-way ANOVA, revealing an effect of C3 fragment (p<0.0001), genotype (p<0.0001) and C3 fragment X genotype (p<0.0001). Multiple comparisons were performed using Tukey’s test, and p-values <0.05 are shown on the graph. C-D) Analysis of data from D, organized by independent variable (Abca4 genotype and Cfd genotype, respectively). Within each C3 fragment, data are represented relative to the respective control conditions ( Abca4 +/+ or Cfd +/+ ). Data were analyzed using a two-way ANOVA, revealing an effect of C3 fragment X genotype for the Cfd genotype (p<0.0001) but not Abca4 genotype (p=0.6). Multiple comparisons were performed using Šídák’s test, and p-values <0.05 are shown on the graph. Each data point is a measurement from a single animal, and data are represented as mean +/- 95% C.I. for all graphs.

Article Snippet: C3 labeling was quantified in mouse eyecup structures, such as the RPE and choroid, using antibodies generated against full-length mouse C3 protein (referred to as “anti-C3”, MP Biomedicals) or purified mouse C3d (referred to as “anti-C3d”, R&D Systems) ( ).

Techniques: Molecular Weight, High Molecular Weight, Control