Immune Response

This video demonstrates in vivo imaging to study the neutrophil recruitment dynamics at an infection site in an immunocompromised, transgenic mouse with GFP-expressing neutrophils. It involves injecting luminescent bacteria to cause an infection. This leads to neutrophil recruitment to the infection site, whose tracking is done by imaging.

In this video, we demonstrate the activation of bone marrow-derived macrophages in response to bacterial lipopolysaccharide and intravenous immunoglobulin.

This video demonstrates the activation of a mouse's peritoneal macrophages using intravenous immunoglobulin and bacterial lipopolysaccharide. The co-stimulation activates the peritoneal macrophages into anti-inflammatory macrophages possessing immune regulatory activity.

This video demonstrates an ex vivo technique to induce brain cell death mediated through cytotoxic CD8+ T cells. Upon obtaining brain slices, activated oligodendrocyte-directed CD8+ T cells are transferred onto the slices to target the myelin sheath and oligodendrocytes. Post-incubation, the damage to myelin and neuronal death can be assessed histologically in the regions of interest.

In this video, we describe a protocol to test the efficacy of an acellular pertussis vaccine against Bordetella pertussis infection in mice. Post-vaccination, the mice were subjected to infection, and their tissue homogenate was cultured to analyze the bacterial colonies as a readout of the vaccine-induced protective immunity.

In this video, we describe a method to study the organelle dynamics in B lymphocytes following their activation with antigen-coated microbeads.

This video demonstrates B cell activation in vitro. The process involves antigen interaction with B cell receptors, leading to cytoskeleton remodeling, immune synapse formation, lysosome movement, antigen internalization, processing, and subsequent presentation on MHC molecules for B cell activation.

This video demonstrates a technique to generate a chemical-induced murine model of colitis — an inflammatory bowel disease. The mouse is allowed to consume a dextran sodium sulfate (DSS) solution for an adequate duration. Upon consumption, DSS damages the mucus and epithelial layer barrier in the colon, allowing gut microbes to enter the underlying tissue — where they are sensed by the resident immune cells to mediate an exaggerated immune response, resulting in inflammation.

In this video, we demonstrate the effect of different anti-c-fms antibody concentrations on osteoclastogenesis, which is the process of osteoclast formation from osteoclast progenitors.

This video demonstrates the quantification of inflammatory mediators during infection by incubating human lung-tissue-derived immune cells with Haemophilus influenzae. Flow cytometry is used to measure cytokine fluorescence in labeled lymphocytes, correlating with the production of pro-inflammatory cytokines in response to bacterial infection.

In this video, we demonstrate an in vitro chemiluminescence assay to detect the generation of reactive oxygen species by neutrophils upon exposure to an opsonized bacterial biofilm.

This video demonstrates an in vitro assay to study neutrophil-biofilm interaction. The pathogenic bacteria embedded in the biofilm and isolated neutrophils were tagged using fluorescent labels, and the immune response by the neutrophils and the evasion of the immune response by the bacteria were assessed using a fluorescence microscope.

This video demonstrates a method to detect NLRP3 inflammasome activation in macrophages using fluorescent reporter probes. The cells are treated with potassium ionophores and glycine to induce inflammasome assembly and caspase-1 activation. Fluorescent reporter probes visualize activated caspase-1, and cells are stained with a fluorescent dye for nuclei visualization.

This video demonstrates a technique to study NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome formation in primary macrophages via immunofluorescence. The macrophages are first primed with bacterial lipopolysaccharide (LPS) to upregulate NLRP3 protein expression. Exposing the macrophages to nigericin—a potassium ionophore—leads to the activation of NLRP3 and the formation of inflammasomes, which are visualized via immunofluorescence.

This video demonstrates the lactate dehydrogenase assay to detect inflammasome-mediated macrophage death. The macrophages are exposed to lipopolysaccharide for priming, followed by exposure to nigericin to cause inflammasome-induced cell death, which is determined by the lactate dehydrogenase assay.

This video demonstrates the induction and visualization of neutrophil extracellular traps or NETs in pre-labeled neutrophils using patient serum containing anti-neutrophil cytoplasmic antibodies. Furthermore, using an impermeable DNA dye and fluorescence microscopy enables the visualization of NETs.

This video demonstrates lipid isolation from human neutrophils by a biphasic solvent system using methanol and chloroform.

In this video, we demonstrate a cytotoxicity assay to assess Cryptococcus neoformans, a pathogenic fungus, infection in macrophages. The cytotoxicity is determined by the release of cytoplasmic lactate dehydrogenase enzyme due to macrophage lysis caused by Cryptococcus neoformans infection.

This video demonstrates a permeable membrane insert-based infection system to assess the impact of secreted bacterial toxins. By eliminating direct contact between the bacterial pathogen and the host cells using a permeable membrane, this technique allows for studying the effect of toxins secreted by pathogenic bacteria on mammalian host cells.

This video demonstrates a permeable membrane insert system to investigate the impact of bacterial toxins on host cells in a controlled and isolated manner. This approach allows for the selective exposure of the cells to the toxins while maintaining a physical separation that mimics the natural host-pathogen interaction.

This video demonstrates the bacterial adherence assay to evaluate GFP-tagged bacterial adherence to epithelial cell culture to study the dynamics of host-pathogen interactions using fluorescence microscopy-based imaging.

This video demonstrates a technique for detecting local and global calcium ion response upon Shigella infection of human epithelial cells. Shigella invades host cells and releases invasion effectors, impacting intracellular calcium levels. The amplitude and frequency of the local and global cytosolic calcium are studied using a fluorescent indicator.

This video analyzes the immune synapse formation between T cells in unpurified pan-leukocyte preparations and Staphylococcus aureus enterotoxin B, SEB-loaded Raji cells. CD3 and F-actin enrichment is observed in the immune synapse using imaging flow cytometry.

This video demonstrates an assay to study mesenchymal stem cell (MSC) regulation of macrophage phagocytosis in a co-culture. Upon co-culturing MSC with macrophages, non-opsonized zymosan particles conjugated to a pH-sensitive fluorophore are added to be phagocytosed by the macrophages. With the increase in phagocytosis, the fluorescence intensity rises, allowing the determination of MSC-mediated regulation of phagocytic activity.

In this video, we demonstrate the intracisternal delivery of Neisseria meningitidis into a mouse model to generate meningitis infection.

In this video, we describe a method to identify the small-molecule kinase inhibitors that modulate the apoptosis of self-reactive CD4+CD8+ double-positive immature thymocytes. Apoptosis is induced in the double-positive thymocytes by activating them with anti-CD3- and anti-CD28-coated magnetic beads; this is followed by a small-molecule inhibitor treatment and flow cytometry analysis to detect if the inhibitors modulate the apoptotic marker expression.

In this video, we describe a procedure to perform a nano-injection of a positive-sense, single-stranded RNA virus into adult male Drosophila flies and subsequently study the antiviral responses initiated due to the infection. Polymerase chain reaction analysis identifies the upregulation of specific genes in the infected flies that indicate the activation of immune response pathways including RNA interference and JAK/STAT signaling.

This video demonstrates the hematoxylin and eosin (H&E) staining method to evaluate colon damage in a murine model of DSS-induced colitis — an inflammatory bowel disease. Upon isolating the colon from a DSS-treated mouse and obtaining sections of the tissue, H&E staining of the sections helps identify the inflammation-mediated tissue damage.

In this video, we describe the methodology for setting up an ex vivo gut organ culture system to study the interactions between mouse intestinal tissue fragments and specific gut bacteria. The device consists of two pairs of input-output ports, the first connecting the intestinal tissue lumen and supplying the specific bacterial suspension into it, and the second continuously supplying media to the device's wells to maintain ex vivo tissue viability.

This video demonstrates an in vitro technique to study the impact of antimicrobial treatment on Pseudomonas aeruginosa (Pa) aggregates. Fluorescently-labeled Pa cells are grown as aggregates, mimicking the growth pattern during infection. Upon challenging the aggregates with a sublethal concentration of the antibiotic colistin, the real-time assessment of the bacteria-antibiotic interaction is performed via fluorescence microscopy.

This video demonstrates an in vitro quantification technique to determine Listeria monocytogenes infection of macrophages by the colony-forming unit assay. The bacterial colonies on the agar plate represent the intracellular bacterial population that escapes the host-defense mechanism and survives within the macrophages.

In this video, we quantify intracellular and extracellular Listeria monocytogenes, an intracellular pathogenic bacteria, following their infection of cultured macrophages in vitro using flow cytometry.

This video demonstrates the nano-injection of bacterial suspension into the fly body cavity, resulting in bacterial multiplication and infection. The fly's immune response clears some bacteria, while others escape immune clearance and survive within the host causing an infection.

This video demonstrates a technique to infect Drosophila by introducing a pathogenic bacteria directly into their body cavity. This method bypasses epithelial barriers and other passive defense mechanisms, allowing for the induction of systemic infection. Upon infection, the resulting immune response is assessed by monitoring fly mortality and performing downstream assays.

In this video, we demonstrate a technique for measuring the E. coli bacterial load after injecting E. coli into the thorax of Drosophila melanogaster.

In this video, we demonstrate the cytopathic effect assay to determine the tissue culture infective viral dose of Drosophila C virus on Drosophila S2* cells. A range of viral concentrations are used to infect the cultured cells. The proportion of cells exhibiting structural changes is determined, and this data is used to calculate the tissue culture infective dose.

This video demonstrates a method to induce ocular surface inflammation and meibomian gland dysfunction in a murine model. Stimulation of the mouse's immune system using an immunogen and later restimulation with the same immunogen promotes ocular surface inflammation, which causes plugging of meibomian gland secretion through neutrophil-produced aggNETs and leads to dry eye disease.

This video demonstrates the activation of caspase proteins in human macrophages using bimolecular fluorescence complementation reporter proteins. The pro-domains of caspase-1 are fused with non-fluorescent fragments of Venus proteins, which are recruited to inflammasome complexes. The proximity of inflammasomes induces the refolding and fluorescence of Venus fragments, confirming caspase activation in the macrophages.

This video demonstrates the effect of tobacco product preparations, TPPs, on cytokine production from human peripheral blood mononuclear cells using flow cytometry. Treatment of the cells with TPP downregulates the production of pro-inflammatory cytokines, which is estimated after lipopolysaccharide stimulation, followed by immunostaining and flow cytometry analysis.

In this video, we demonstrate the preparation of in vitro biofilm by S. aureus in a poly-L-Lysine-coated multi-well plate. The biofilm-formed plate can be used for downstream experiments.

This video demonstrates an in vitro technique to stimulate lymphocytes via non-typeable Haemophilus influenzae (NTHi) and to assess the immune response. Incubating isolated peripheral blood mononuclear cells (PBMCs) with NTHi causes the bacterial cells to stimulate T lymphocytes, leading to cytokine production. Upon inhibiting the secretion of cytokines, immunofluorescence staining is performed to detect the accumulated intracellular cytokines in stimulated T lymphocytes.

This video demonstrates the assessment of chemical-induced colitis via immunohistochemical staining of mouse colon tissue. In a stained tissue section, the presence of a large number of immune-responsive cells in the damaged tissue represents the infiltration of immune cells during colitis.

In this video, we study the effect of a whole smoke-conditioned medium, a combustible tobacco product preparation, on K562 cell killing by effector peripheral blood mononuclear cells.

This video demonstrates an in vivo technique to assess a test antigen by inducing skin inflammation in a murine model. The test antigen—a hapten in an oil/acetone solution—is topically applied to the skin of the mouse ear, and inflammation of the skin is assessed after an adequate period.

This video demonstrates a punch biopsy procedure to create a precise wound in a mouse model. The excision exposes the subcutaneous layer of the skin, providing a suitable site for studying immune responses to localized pathogen infection.