Name: evaluation of the interplay between the complement protein c1q and hyaluronic acid in promoting cell adhesion
Uploaded: 2019-06-15T13:00:00
Description: Watch this Scientific Journal Video about Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion at JoVE.com

We thank Ivan Donati for providing of HA, Leonardo Amadio, Gabriella Zito (Department of Gynaecology of IRCCS &#34;Burlo Garofolo&#34;, Trieste, Italy) and Andrea Romano (Operative Clinical Unit of Anatomy and Pathological Histology, Cattinara Hospital, Trieste, Italy) for the tissue sample collection. We thank also Nicol&#242; Morosini for the help in the video preparation and Alex Coppola, the voice. This work was supported by grants from the Institute for Maternal and Child Health, IRCCS &#34;Burlo Garofolo&#34;, Trieste, Italy (RC20/16) and Fondazione Cassa di Risparmio Trieste to R.Bulla.

Tissue samples from patients were collected after informed consent following approval of the ethical considerations by the Institutional Board of the University Hospital of Trieste, Italy.
1. Tumor cell isolation and culture (Day 1)
<ol>
	<li>Isolate human mesothelioma cells from MPM solid specimens. Finely mince the tissue with a cutter to obtain fragments of about 2-3 mm2 in size and incubate in 5 mL of digestion solution composed of Hanks&#39; Balanced Salt Solution (HBSS) supp...

<ol>
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N., Birkinshaw, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronic+acid+solutions:+A+processing+method+for+efficient+chemical+modification.">Hyaluronic acid solutions: A processing method for efficient chemical modification.</a> Journal of Applied Polymer Science. 130 (1), 145-152 (2013).</li><li>Itano, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+primary+structure,+complex+turnover+regulation+and+multiple+roles+of+hyaluronan.">Simple primary structure, complex turnover regulation and multiple roles of hyaluronan.</a> Journal of Biochemistry. 144 (2), 131-137 (2008).</li><li>Agostinis, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+alternative+role+of+C1q+in+cell+migration+and+tissue+remodeling:+contribution+to+trophoblast+invasion+and+placental+development.">An alternative role of C1q in cell migration and tissue remodeling: contribution to trophoblast invasion and placental development.</a> Journal of Immunology. 185 (7), 4420-4429 (2010).</li><li>Agostinis, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complement+Protein+C1q+Binds+to+Hyaluronic+Acid+in+the+Malignant+Pleural+Mesothelioma+Microenvironment+and+Promotes+Tumor+Growth.">Complement Protein C1q Binds to Hyaluronic Acid in the Malignant Pleural Mesothelioma Microenvironment and Promotes Tumor Growth.</a> Frontiers in Immunology. 8, 1559 (2017).</li><li>Bossi, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=C1q+as+a+unique+player+in+angiogenesis+with+therapeutic+implication+in+wound+healing.">C1q as a unique player in angiogenesis with therapeutic implication in wound healing.</a> Proceedings of the National Academy of Sciences of the United States of America. 111 (11), 4209-4214 (2014).</li><li>Hosszu, K. 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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronan.">Hyaluronan.</a> Journal of the Federation of American Societies for Experimental Biology. 6 (7), 2397-2404 (1992).</li><li>Gaboriaud, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+crystal+structure+of+the+globular+head+of+complement+protein+C1q+provides+a+basis+for+its+versatile+recognition+properties.">The crystal structure of the globular head of complement protein C1q provides a basis for its versatile recognition properties.</a> Journal of Biological Chemistry. 278 (47), 46974-46982 (2003).</li><li>Lam, J., Truong, N. 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We describe&#160;an easy method to investigate how the complement component C1q, interacting with hyaluronic acid, is able to modulate the behavior of primary cells isolated from human tumor tissues. Both HA and C1q are abundantly present in the tissue microenvironment both under physiological and pathological conditions, participating to several cell biological processes. For instance, C1q has been shown to be present in the microenvironment of the placenta where it favors extravillous trophoblast invasion of the matern...

The tumor microenvironment (TME) influences cancer development and progression since it can provide a permissive niche for cell survival, growth and invasion. The identification of new key players in TME may be useful for the discovery of new molecular tools for target therapy. TME includes a complex and dynamic network of non-malignant cells, such as endothelial cells, fibroblasts and cells of the immune system, embedded in the surrounding extracellular matrix (ECM) components including collagens, laminins, fibronectins, proteoglycans and hyaluronans. Both tumor and non-tumor cells synthesize and secrete ECM components together with cytokines, chemokines, growth factors and inflammatory and matrix remodeling enzymes that overall alter the physical, chemical and signaling properties of TME. Among these constituents, hyaluronic acid (HA) has emerged to exert a crucial role in tumor biology. Despite its simple chemical composition, HA, together with its HA-binding molecules (hyaladherins), can modulate angiogenesis, immune system responsiveness and ECM remodeling in a size and concentration dependent manner1.
The complement (C) system is also part of the local TME, which has recently received increasing attention. The C system encompasses a set of soluble and membrane-bound proteins involved in the first line of defense against non-self-cells, unwanted host elements and pathogens. Functionally, the C links the two-effector arms of innate and adaptive systems to promote either direct cell killing or mounting of an inflammatory response2. C activation can suppress tumor growth, by destroying cancer cells or inhibiting their outgrowth, but it has become increasingly clear that it can possess a tumor-promoting activity by sustaining chronic inflammation, promoting the establishment of an immunosuppressive milieu, inducing angiogenesis, and activating cancer-related signaling pathways3. In this context, C1q, the first recognition molecule of the classical pathway of the C system has emerged to exert important functions in the tumor microenvironment independently of C activation4. C1q has been shown to be expressed locally by a range of human malignant tumors, where it can favor cancer cell adhesion, migration and proliferation in addition to angiogenesis and metastasis5. Interestingly C1q interacts with a major constituent of the ECM such as HA.
We developed a technique to isolate the primary cancer cells from the tumor mass. Furthermore, we created the matrix, which can stimulate tumor microenvironment, particularly the interaction between C1q and high molecular weight hyaluronic acid. C1q bound to HA was able to induce adhesion of the tumor cells.

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evaluation of the interplay between the complement protein c1q and hyaluronic acid in promoting cell adhesion

It has been increasingly demonstrated that the tumor microenvironment plays an active role in neoplasia growth and metastasis. Through different pathways, tumor cells can efficiently recruit stromal, immune and endothelial cells by secreting stimulatory factors, chemokines and cytokines. In turn, these cells can alter the signaling properties of the microenvironment by releasing growth-promoting signals, metabolites and extracellular matrix components to sustain high proliferation and metastatic competence. In this context, we identify that the complement component C1q, highly expressed locally by a range of human malignant tumors, upon interacting with the extracellular matrix hyaluronic acid, strongly affects the behavior of primary cells isolated from human tumor specimens. Here, we describe&#160;a method to test how C1q bound to hyaluronic acid (HA) impacts tumor cell adhesion, underlying the fact that the biological properties of key components of the extracellular matrix (in this case HA) can be shaped by bioactive signals toward tumor progression.

HA is a negatively charged high-molecular-weight polysaccharide, which is made up of repeating (&#946;,1-4)-D-glucuronic acid-(&#946;,1-3)-N-acetyl-D-glucosamine disaccharide units (Figure 1B)7. The occurrence of the binding of HA on the 96-well plate as well as the efficiency of its immobilization were tested taking advantage of biotinylated HA (bio-HA). Different concentrations of Bio-HA, ranging from 10 &#181;g/mL to 1 mg/mL, were r...

Watch this Scientific Journal Video about Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion at JoVE.com

Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion

The complement component C1q is a pro-inflammatory molecule highly expressed in the tissue microenvironment that can interact with the extracellular matrix. Here, we describe&#160;a method to test how C1q bound to hyaluronic acid impacts cell adhesion.

It has been increasingly demonstrated that the tumor microenvironment plays an active role in neoplasia growth and metastasis. Through different pathways, ...

A comprehensive procedure to evaluate the interplay between the complement protein C1q and hyaluronic acid in promoting cell adhesion. We have recently defined that the complement component C1q a molecule of the innate immune system is highly expressed in the tumor and placenta microenvironment and is able to interact with component of the extracellular matrix. In this case, hyaluronic acid.We propose a method for studying the biological functions of proteins throughout the ecronomic environment. In order to investigate the ability of these molecules to shape the cell division properties of extracellular matrix factors. In order to study how this interaction can be sensed by the cells present in the tissue of the environment, we set up this easy method in which binary cells derived from human tissues were allowed to adhere to C1q bound to extracellular matrix, in this case hyaluronic acid.For coating procedure the first step is the binding of high molecular weight hyaluronic acid to 96 well tissue coated microplate. For coating, hyaluronic acid is diluted in 0.1 mole carbon buffer PH 9.6 at a concentration of 15 micrograms per milliliter. And gently pipeting is requited to achieve a homogeneous solution.A 100 microliters of the solution are used to coat the wells. The plate is then transferred at four degrees Celsius overnight. Next day vacuum aspirate the treated wells.Wash once with dPBS. Add either C1q or BSA in the corresponding wells. C1q is nowadays commercially available at a concentration of one milligram per milliliter and it is diluted at a concentration of 25 micrograms per milliliter.And dPBS containing 0.5%BSA and 0.7 millimoles calcium and magnesium and divalent cations. BSA LPS free is used at the concentration of 0.5%and date PBF. Plate is then transferred at four degrees Celsius overnight.C1q dose dependent interactions with immobilized hyaluronic acid is determined by enzyme linked immuno SA.Cells labeling with fast DiI. The lipophilic tracer fast DiI is used to label the cells of interest. Cells resuspended in dPBS are used at the concentration of one million cells per milliliter.Fast DiI is diluted one to 100 directly into the cell suspension. The cell suspension is mixed manually and transferred at 37 degrees Celsius for 15 minutes. After five minutes incubation, mix the cell suspension and repeat this operation twice more.To remove the excess of fast DiI, add 10 milliliters of dPBS. Pivot gently up and down and centrifuge at 250 g for seven minutes. Resuspend the cell pellet in one milliliter of human endophilical serum free medium in the presence of 0.1%BSA.Cells adhesion on hyaluronic acid C1q matrices. Vacuum aspirate the dPBS from the coated wells. Distribute 100 microliters of labeled cell suspension to the coated wells.200 microliters of labeled cells are taken apart in an ependure tube to be used for standard curve generation. Incubate the plate for 35 minutes at 37 degrees Celsius. Take out the plate from the incubator.Gently aspirate the unbalanced cells. Wash once with dPBS containing 0.5%BSA and 0.7 millimoles calcium and magnesium. Lys the adherent cells by adding 200 microliters of lysis buffer.At the same time prepare the standard curve upon one to two serial dilution of the labeled cells in lysis buffer. Perform the reading of the florescence signal at infinite F 200 T-can instrument using 544 nanometers as excitation wavelength and 590 nanometers as emission wavelength. Representative results.As shown by the representative results, it is evident that cell adhesion on hyaluronic acid found C1q as strongly enhanced in comparison with HA alone or HA bound BSA. The percent of adherent cells on each matrix is calculated on the basis of the standard curve.Conclusions. In our experiments first of all we evaluated the ability of the complement component C12 to bind the extracellular matrix in this case hyaluronic acid using an arisal metal.Secondly we analyzed the capability of human primary cells stained with fluorescent dye to pursue bound hyaluronic acid. The model that we proposed in this study is an easier faster and cheaper method in alternative to the 3D model of extracellular matrix scaffolds for the evaluation on this cellular response to a combination of stimuli.

evaluation-interplay-between-complement-protein-c1q-hyaluronic-acid

Research

JoVE Journal

Immunology and Infection

Depletion of Specific Cell Populations by Complement Depletion

The purification of immune cell populations is often required in order to study their unique functions. In particular, molecular approaches such as real-time PCR and microarray analysis require the isolation of cell populations with high purity. Commonly used purification strategies include fluorescent activated cell sorting (FACS), magnetic bead separation and complement depletion. Of the three strategies, complement depletion offers the advantages of being fast, inexpensive, gentle on the cells and a high cell yield. The complement system is composed of a large number of plasma proteins that when activated initiate a proteolytic cascade culminating in the formation of a membrane-attack complex that forms a pore on a cell surface resulting in cell death1. The classical pathway is activated by IgM and IgG antibodies and was first described as a mechanism for killing bacteria. With the generation of monoclonal antibodies (mAb), the complement cascade can be used to lyse any cell population in an antigen-specific manner. Depletion of cells by the complement cascade is achieved by the addition of complement fixing antigen-specific antibodies and rabbit complement to the starting cell population. The cells are incubated for one hour at 37&deg;C and the lysed cells are subsequently removed by two rounds of washing. MAb with a high efficiency for complement fixation typically deplete 95-100% of the targeted cell population. Depending on the purification strategy for the targeted cell population, complement depletion can be used for cell purification or for the enrichment of cell populations that then can be further purified by a subsequent method.

To effectively study the function of immune cell populations their purification is often required. Complement depletion is a fast and inexpensive technique for the isolation of immune cell populations with high purity.

The purification of immune cell populations is often required in order to study their unique functions.  In particular, molecular approaches such as ...

Measuring the 50% Haemolytic Complement (CH50) Activity of Serum

The complement system is a group of proteins that when activated lead to target cell lysis and facilitates phagocytosis through opsonisation. Individual complement components can be quantified however this does not provide any information as to the activity of the pathway. The CH50 is a screening assay for the activation of the classical complement pathway (Fig 1) and it is sensitive to the reduction, absence and/or inactivity of any component of the pathway. The CH50 tests the functional capability of serum complement components of the classical pathway to lyse sheep red blood cells (SRBC) pre-coated with rabbit anti-sheep red blood cell antibody (haemolysin). When antibody-coated SRBC are incubated with test serum, the classical pathway of complement is activated and haemolysis results. If a complement component is absent, the CH50 level will be zero; if one or more components of the classical pathway are decreased, the CH50 will be decreased. A fixed volume of optimally sensitised SRBC is added to each serum dilution. After incubation, the mixture is centrifuged and the degree of haemolysis is quantified by measuring the absorbance of the haemoglobin released into the supernatant at 540nm. The amount of complement activity is determined by examining the capacity of various dilutions of test serum to lyse antibody coated SRBC. This video outlines the experimental steps involved in analysing the level of complement activity of the classical complement pathway.

Measuring the 50% Haemolytic Complement CH50 Activity of Serum

The classical pathway is activated by antibody and culminates in target cell lysis. The CH50 assay provides a measure of the complement activity of a serum sample. This video demonstrates the steps involved in determining the CH50 of a serum sample, the calculations and interpreting of results.

The complement system is a group of proteins that when activated lead to target cell lysis and facilitates phagocytosis through opsonisation. Individual ...

Introducing Shear Stress in the Study of Bacterial Adhesion

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the initial and determining step of the pathogenesis. Although experimentally adhesion is mostly studied in static conditions adhesion actually takes place in the presence of flowing liquid. First encounters between bacteria and their host often occur at the mucosal level, mouth, lung, gut, eye, etc. where mucus flows along the surface of epithelial cells. Later in infection, pathogens occasionally access the blood circulation causing life-threatening illnesses such as septicemia, sepsis and meningitis. A defining feature of these infections is the ability of these pathogens to interact with endothelial cells in presence of circulating blood. The presence of flowing liquid, mucus or blood for instance, determines adhesion because it generates a mechanical force on the pathogen. To characterize the effect of flowing liquid one usually refers to the notion of shear stress, which is the tangential force exerted per unit area by a fluid moving near a stationary wall, expressed in dynes/cm2. Intensities of shear stress vary widely according to the different vessels type, size, organ, location etc. (0-100 dynes/cm2). Circulation in capillaries can reach very low shear stress values and even temporarily stop during periods ranging between a few seconds to several minutes 1. On the other end of the spectrum shear stress in arterioles can reach 100 dynes/cm2 2. The impact of shear stress on different biological processes has been clearly demonstrated as for instance during the interaction of leukocytes with the endothelium 3. To take into account this mechanical parameter in the process of bacterial adhesion we took advantage of an experimental procedure based on the use of a disposable flow chamber 4. Host cells are grown in the flow chamber and fluorescent bacteria are introduced in the flow controlled by a syringe pump. We initially focused our investigations on the bacterial pathogen Neisseria meningitidis, a Gram-negative bacterium responsible for septicemia and meningitis. The procedure described here allowed us to study the impact of shear stress on the ability of the bacteria to: adhere to cells 1, to proliferate on the cell surface 5and to detach to colonize new sites 6 (Figure 1). Complementary technical information can be found in reference 7. Shear stress values presented here were chosen based on our previous experience1 and to represent values found in the literature. The protocol should be applicable to a wide range of pathogens with specific adjustments depending on the objectives of the study.

During the infection process, a key step is the adhesion of pathogens with host cells. In most instances this adhesion step occurs in the presence of mechanical stress generated by flowing liquid. We describe a technique that introduces shear stress as an important parameter in the study of bacterial adhesion.

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the ...

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Continuous advancements in noninvasive imaging modalities such as magnetic resonance imaging (MRI) have greatly improved our ability to study physiological or pathological processes in living organisms. MRI is also proving to be a valuable tool for capturing transplanted cells in vivo. Initial cell labeling strategies for MRI made use of contrast agents that influence the MR relaxation times (T1, T2, T2*) and lead to an enhancement (T1) or depletion (T2*) of signal where labeled cells are present. T2* enhancement agents such as ultrasmall iron oxide agents (USPIO) have been employed to study cell migration and some have also been approved by the FDA for clinical application. A drawback of T2* agents is the difficulty to distinguish the signal extinction created by the labeled cells from other artifacts such as blood clots, micro bleeds or air bubbles. In this article, we describe an emerging technique for tracking cells in vivo that is based on labeling the cells with fluorine (19F)-rich particles. These particles are prepared by emulsifying perfluorocarbon (PFC) compounds and then used to label cells, which subsequently can be imaged by 19F MRI. Important advantages of PFCs for cell tracking in vivo include (i) the absence of carbon-bound 19F in vivo, which then yields background-free images and complete cell selectivityand(ii) the possibility to quantify the cell signal by 19F MR spectroscopy.

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Tracking of cells using MRI has gained remarkable attention in the past years. This protocol describes the labeling of dendritic cells with fluorine (19F)-rich particles, the in vivo application of these cells, and monitoring the extent of their migration to the draining lymph node with 19F/1H MRI and 19F MRS.

Continuous  advancements in noninvasive imaging modalities such as magnetic resonance  imaging (MRI) have greatly improved our ability to study ...

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes

T lymphocyte adhesion is required for multiple T cell functions, including migration to sites of inflammation and formation of immunological synapses with antigen presenting cells. T cells accomplish regulated adhesion by controlling the adhesive properties of integrins, a class of cell adhesion molecules consisting of heterodimeric pairs of transmembrane proteins that interact with target molecules on partner cells or extracellular matrix. The most prominent T cell integrin is lymphocyte function associated antigen (LFA)-1, composed of subunits &#945;L and &#946;2, whose target is the intracellular adhesion molecule (ICAM)-1. The ability of a T cell to control adhesion derives from the ability to regulate the affinity states of individual integrins. Inside-out signaling describes the process whereby signals inside a cell cause the external domains of integrins to assume an activated state. Much of our knowledge of these complex phenomena is based on mechanistic studies performed in simplified in&#160;vitro model systems. The T lymphocyte adhesion assay described here is an excellent tool that allows T cells to adhere to target molecules, under static conditions, and then utilizes a fluorescent plate reader to quantify adhesiveness. This assay has been useful in defining adhesion-stimulatory or inhibitory substances that act on lymphocytes, as well as characterizing the signaling events involved. Although described here for LFA-1 - ICAM-1 mediated adhesion; this assay can be readily adapted to allow for the study of other adhesive interactions (e.g.&#160;VLA-4 - fibronectin).

Static adhesion assay is a powerful tool that can be used to model the interactions between T lymphocytes and other cell types. Interactions are generated by injecting labeled T cells into wells coated with adhesion molecules, while a plate reader is used to quantify the number of adherent cells following serial washes.

T lymphocyte adhesion is required for multiple T cell functions, including migration to sites of inflammation and formation of immunological synapses with ...

Assay of Adhesion Under Shear Stress for the Study of T Lymphocyte-Adhesion Molecule Interactions

Overall, T cell adhesion is a critical component of function, contributing to the distinct processes of cellular recruitment to sites of inflammation and interaction with antigen presenting cells (APC) in the formation of immunological synapses. These two contexts of T cell adhesion differ in that T cell-APC interactions can be considered static, while T cell-blood vessel interactions are challenged by the shear stress generated by circulation itself. T cell-APC interactions are classified as static in that the two cellular partners are static relative to each other. Usually, this interaction occurs within the lymph nodes. As a T cell interacts with the blood vessel wall, the cells arrest and must resist the generated shear stress.1,2 These differences highlight the need to better understand static adhesion and adhesion under flow conditions as two distinct regulatory processes. The regulation of T cell adhesion can be most succinctly described as controlling the affinity state of integrin molecules expressed on the cell surface, and thereby regulating the interaction of integrins with the adhesion molecule ligands expressed on the surface of the interacting cell. Our current understanding of the regulation of integrin affinity states comes from often simplistic in vitro model systems. The assay of adhesion using flow conditions described here allows for the visualization and accurate quantification of T cell-epithelial cell interactions in real time following a stimulus. An adhesion under flow assay can be applied to studies of adhesion signaling within T cells following treatment with inhibitory or stimulatory substances. Additionally, this assay can be expanded beyond T cell signaling to any adhesive leukocyte population and any integrin-adhesion molecule pair.

This flow adhesion assay provides a simple, high impact model of T cell-epithelial cell interactions. A syringe pump is used to generate shear stress, and confocal microscopy captures images for quantification. The goal of these studies is to effectively quantify T cell adhesion using flow conditions.

Overall, T cell adhesion is a critical component of function, contributing to the distinct processes of cellular recruitment to sites of inflammation and ...

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research is deciphering how these dynamic protein complexes act to integrate signals from multiple sources in order to direct a specific biological response, and how this becomes deregulated in many disease settings. Despite the importance of this key biochemical mechanism, there is a lack of experimental techniques that can facilitate the specific and sensitive deconvolution of these multi-molecular signaling complexes.
Here this shortcoming is addressed through the combination of a protein complementation assay with a conformation-specific nanobody, which we have termed Bimolecular Complementation Affinity Purification (BiCAP). This novel technique facilitates the specific isolation and downstream proteomic characterization of any pair of interacting proteins, to the exclusion of un-complexed individual proteins and complexes formed with competing binding partners. 
The BiCAP technique is adaptable to a wide array of downstream experimental assays, and the high degree of specificity afforded by this technique allows more nuanced investigations into the mechanics of protein complex assembly than is currently possible using standard affinity purification techniques.

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification BiCAP

This manuscript describes the protocol for Bimolecular Complementation Affinity Purification (BiCAP). This novel method facilitates the specific isolation and downstream proteomic characterization of any two interacting proteins, while excluding un-complexed individual proteins as well as complexes formed with competing binding partners.

The assembly of protein complexes is a central mechanism underlying the regulation of many cell signaling pathways. A major focus of biomedical research ...

Dynamic Adhesion Assay for the Functional Analysis of Anti-adhesion Therapies in Inflammatory Bowel Disease

Gut homing of immune cells is important for the pathogenesis of inflammatory bowel diseases (IBD). Integrin-dependent cell adhesion to addressins is a crucial step in this process and therapeutic strategies interfering with adhesion have been successfully established. The anti-&#945;4&#946;7 integrin antibody, vedolizumab, is used for the clinical treatment of Crohn&#39;s disease (CD) and ulcerative colitis (UC) and further compounds are likely to follow.
The details of the adhesion procedure and the action mechanisms of anti-integrin antibodies are still unclear in many regards due to the limited available techniques for the functional research in this field.
Here, we present a dynamic adhesion assay for the functional analysis of human cell adhesion under flow conditions and the impact of anti-integrin therapies in the context of IBD. It is based on the perfusion of primary human cells through addressin-coated ultrathin glass capillaries with real-time microscopic analysis. The assay offers a variety of opportunities for refinements and modifications and holds potentials for mechanistic discoveries and translational applications.

Dynamic adhesion of immune cells to the vessel wall is a prerequisite for gut homing. Here, we present a protocol for a functional in vitro assay for the impact analysis of anti-integrin antibodies, chemokines or other factors on the dynamic cell adhesion of human cells using addressin-coated capillaries.

Gut homing of immune cells is important for the pathogenesis of inflammatory bowel diseases (IBD). Integrin-dependent cell adhesion to addressins is a ...

Evaluation of Host-Pathogen Responses and Vaccine Efficacy in Mice

Vaccines are a 20th century medical marvel. They have dramatically reduced the morbidity and mortality caused by infectious diseases and contributed to a striking increase in life expectancy around the globe. Nonetheless, determining vaccine efficacy remains a challenge. Emerging evidence suggests that the current acellular vaccine (aPV) for Bordetella pertussis (B. pertussis) induces suboptimal immunity. Therefore, a major challenge is designing a next-generation vaccine that induces protective immunity without the adverse side effects of a whole-cell vaccine (wPV). Here we describe a protocol that we used to test the efficacy of a promising, novel adjuvant that skews immune responses to a protective Th1/Th17 phenotype and promotes a better clearance of a B. pertussis challenge from the murine respiratory tract. This article describes the protocol for mouse immunization, bacterial inoculation, tissue harvesting, and analysis of immune responses. Using this method, within our model, we have successfully elucidated crucial mechanisms elicited by a promising, next-generation acellular pertussis vaccine. This method can be applied to any infectious disease model in order to determine vaccine efficacy.

Here we present an elegant protocol for in vivo evaluation of vaccine effectiveness and host immune responses. This protocol can be adapted for vaccine models that study viral, bacterial, or parasitic pathogens.

Vaccines are a 20th century medical marvel. They have dramatically reduced the morbidity and mortality caused by infectious diseases and contributed to a ...

Renal Subcapsular Transplantation of 2'-Deoxyguanosine-Treated Murine Embryonic Thymus in Nude Mice

The thymus is an important central immune organ, which plays an essential role in the development and differentiation of T cells. Thymus transplantation is an important method for investigating thymic epithelial cell function and T cells maturation in vivo. Here we will describe the experimental methods used within our laboratory to transplant 2&#8217;-deoxyguanosine (to deplete donor&#8217;s lymphocytes) treated embryonic thymus into the renal capsule of an athymic nude mouse. This method is both simple and efficient and does not require special skills or devices. The results obtained via this simple method showed that transplanted thymus can effectively support the recipient&#8217;s T cells production. Additionally, several key points with regards to the protocol will be further elucidated.

Renal Subcapsular Transplantation of 2&#039;-Deoxyguanosine-Treated Murine Embryonic Thymus in Nude Mice

We provide a simple and efficient method to transplant 2&#8217;-deoxyguanosine treated E18.5 thymus into the renal capsule of a nude mouse. This method should aide in the study of both thymic epithelial cells function and T cells maturation.

The thymus is an important central immune organ, which plays an essential role in the development and differentiation of T cells. Thymus transplantation ...