https://www.friendbookmark.com/authors/4697/thomass111 Most recent BlogU posts submitted by ThomasS111 https://www.friendbookmark.com/blogpost/34841/blood-brain-barrier-permeabilityBlood-brain Barrier Overview[/FONT][IMG]https://www.creative-diagnostics.com/upload/image/Blood-brain-Barrier-Permeability.jpg" width="320" alt="Blood-brain Barrier Permeability" style="box-sizing: border-box; border: 0px; vertical-align: middle; display: block; max-width: 100%; height: auto; margin-bottom: 15px; margin-left: auto; margin-right: auto;[/IMG][/FONT]The blood-brain barrier is a barrier system in which the capillary endothelial cells in the brain are closely connected to each other while interacting with surrounding pericytes and astrocytes. It precisely controls the exchange of substances between blood and brain tissue, which is essential for maintaining the stability of the microenvironment in the brain. Studies show that the cells that make up the blood-brain barrier regulate the development and function of the blood-brain barrier by expressing tight and adherent connexins, transporters, and related signaling molecules. In addition, neurons and microglia are also involved in the regulation of the blood-brain barrier under physiological and pathological conditions. Recent studies have shown that the occurrence and development of various neurological diseases are accompanied by the destruction of the structure and function of the blood-brain barrier. Therefore, the study of the blood-brain barrier will deepen the understanding of neuro-vascular interactions and provides an important theoretical basis for the diagnosis and treatment of neurological diseases.[/SIZE][/FONT]Blood-brain Barrier Permeability Function[/FONT]As early as the early 20th century, Paul Ehrlich and Edwin Goldmann discovered the existence of a physical barrier between the central nervous system (CNS) and the peripheral blood circulation system. Subsequent studies have found that vascular endothelial cells in the brain are closely linked to each other through various connexins and interact with pericytes and astrocytes to form a special barrier system of the blood-brain barrier (BBB). In the process of maintaining energy supply of the brain and the stability of the microenvironment, BBB permeability plays a huge role in the normal function of the nervous system. For example, BBB permeability strictly limits the entry of neurotoxic substances, inflammatory factors, immune cells, etc. into the CNS, and excretes metabolites and neurotoxic substances in the CNS. Through precise control of blood and brain exchange, BBB maintains ion balance, water balance, and neurotransmitters and hormone levels in the CNS, thereby maintaining the homeostasis of the brain's microenvironment and ensuring proper functioning of the nervous system. Numerous studies have shown that the development and function of BBB are coordinated by vascular endothelial cells and pericytes, astrocytes, microglia, and neurons. BBB's development and dysfunction disrupt the homeostasis of the brain's microenvironment, leading to neuronal cell death and neurological dysfunction. In clinical studies, BBB dysfunction is found in many diseases of the nervous system such as stroke, Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS). The low permeability of the BBB is also a barrier for neuro-therapeutic drugs. Therefore, drug delivery across the blood-brain barrier is also one of the research hotspots. To provide an important theoretical basis for the diagnosis and treatment of neurological diseases, an in-depth study of BBB permeability is essential.[/SIZE][/FONT]Blood-brain Barrier Permeability Research Status[/FONT]In the early stage of cerebral vascular development, the perivascular vascular plexus grows into the brain through angiogenesis under the induction of VEGF. Early developmental cerebral blood vessels have shown many of the characteristics of BBB, including tight and adherent expression of connexins and nutrient transporters, but there are still many endocytic transport vesicles and leukocyte adhesion molecules to regulate the endocytic transport. With the recruitment of pericytes and astrocytes, tight and adherent connexin localization is gradually accurate, endocytic transport is reduced, leukocyte adhesion molecule expression is down-regulated, outward transporter expression is increased, and BBB is gradually matured. In the process, many factors are involved in the development and maturation of BBB, such as VEGF, Wnt, Sonic Hedgehog (Shh), G protein-coupled receptor 124 (Gpr124), and the main promoter superfamily 2a.[/SIZE][/FONT]VEGF is a critical factor in the development of vascular and lymphatic systems, including VEGF-A, VEGF-B, VEGF-C, VEGF-D, and placental growth factor. VEGF mainly passes through three tyrosine kinase receptors, VEGFR1 and VEGFR2, VEGFR3 and co-receptors neuropilins (NRPs) play a role. Vegfr2-deficient mice develop systemic vascular dysplasia and eventually die around 9 days in the embryo. Similarly, homozygous or heterozygous deletions of VEGF can lead to early embryonic death. During embryonic development, neural precursor cells located in the subventricular zone secrete VEGF, which guides the growth of new blood vessels into the brain. Deletion of VEGF in nerve cells leads to decreased vascular density and vascular dysplasia in the cerebral cortex and retina, affecting the establishment and function of BBB.[/SIZE][/FONT]In neural cells, Wnt binds to the Frizzled receptor on vascular endothelial cells, inhibits the degradation of ÃÂ-catenin, promotes the accumulation of ÃÂ-catenin in the cytoplasm into the nucleus and increases the expression of ÃÂ-catenin to induce Dr6 and Troy to promote angiogenesis and BBB formation in the brain. Dr6 and Troy can interact with downstream molecules of VEGF to regulate brain blood vessels and BBB development. In addition, studies have shown that neural progenitor cells in the forebrain and ventricle of mice express Wnt7a and Wnt7b, and neural precursor cells in the hindbrain and spinal dorsal cells express Wnt1, Wnt3a, and Wnt3b. The Wnt/ÃÂ-catenin signaling pathway in CNS vascular endothelial cells is specifically activated during mouse embryonic development. Mice knocked out of Wnt7b developed severe cerebral hemorrhage and ventral vascular dysplasia in the brain, resulting in embryos death from E11.5 to E12.5. In addition, the absence of ÃÂ-catenin in vascular endothelial cells specifically leads to abnormal vascular development in the CNS but does not affect the development of peripheral blood vessels. Studies find that Wnt signaling pathway is also capable of inducing expression of key BBB genes such as glut1.[/SIZE][/FONT]In addition to the Wnt signaling pathway, Gpr124 also plays an important role in the formation of the BBB. Gpr124 belongs to the orphan receptor in the G protein-coupled receptor family and is highly expressed in CNS vascular endothelial cells, specifically mediating brain angiogenesis and BBB development. In mice, knockout of Gpr124 severely affects the survival, growth, and migration into the brain of CNS vascular endothelial cells, resulting in abnormal vascular development in the brain with ventral hemorrhage in the forebrain and spinal cord. Eventually, the embryo is killed. The phenotype of Gpr124 knockout mice is very similar to that of Wnt7b knockout or vascular endothelial cell ÃÂ-catenin knockout mice, both of which are characterized by blood leakage and decreased Glut1 expression, suggesting that these two signaling pathways may be involved in BBB development. Recent studies have shown that Gpr124 acts as a coactivator of Wnt7a and Wnt7b. In addition, Gpr124 can cooperate with Norrin/Frizzled4 to regulate the integrity of CNS angiogenesis and BBB.[/SIZE][/FONT]The Shh signaling pathway plays an important role in the formation and maintenance of BBB. Shh knockdown resulted in a significant down-regulation of tight junction proteins such as Occludin and Claudin-5, while the number of blood vessels in the brain was normal. Specific knockdown of Shh's downstream gene, vascular endothelial cells also leads to down-regulation of tight junction proteins and leads to leakage of plasma proteins from blood vessels in the brain. Unlike the Wnt signaling pathway, the Shh signaling pathway does not regulate angiogenesis and angiogenesis in CNS but significantly regulates BBB formation and integrity. The development and function of BBB are coordinated by a neurovascular network composed of pericytes, astrocytes, microglia, and neurons. Current studies show that neural progenitor cells are mainly involved in the induction of BBB characteristics in early development; then, pericytes and astrocytes are involved in the differentiation and maintenance of BBB characteristics. Deletion of pericytes leads to a significant increase in BBB leakage, endocytic transport, and increased expression of leukocyte adhesion molecules. By comparing the transcription of CNS vascular endothelial cells in PdgfrÃÂ-deficient and wild-type mice, it was found that the connexin and transporter-related genes are involved in BBB formation and maintenance. The expression of related proteins, such as PLVAP and leukocyte adhesion molecules, is significantly increased.[/SIZE][/FONT]Relationship with Disease[/FONT]AD[/FONT]AD is a progressive neurodegenerative disease with progressive memory decline and cognitive impairment as the main clinical symptoms. Its main pathological feature is the deposition of neurotoxic ÃÂ-amyloid in the brain. Studies have shown a significant increase in AÃÂ levels in the brain of familial and sporadic AD patients, but no increase in AÃÂ production, suggesting that AÃÂ clearance abnormalities lead to AÃÂ deposition in the brain. There are multiple transporters on the BBB involved in the clearance of AÃÂ. During the development of AD, abnormalities in BBB clearance of AÃÂ lead to a series of changes in neurovascular units and ultimately to the destruction of BBB.[/FONT]Amyotrophic lateral sclerosis[/FONT]BBB also plays a role in the development of ALS. Studies have shown that plasma components such as albumin, IgG, and complement are significantly elevated in the cerebrospinal fluid and spinal cord of patients with ALS, suggesting that ALS is associated with a blood-brain barrier and BBB destruction. Berislav V. Zlokovic proposed the Zlokovic-Cleveland model for studying the role of BBB in ALS. This model suggests that disruption of BBB can cause plasma proteins to leak into the spinal cord, causing hypoxia and edema in local tissues. Leaked IgG can directly bind to the surface antigen of neurons, and produce ROS and initiate autoimmune reactions, leading to demyelination, disruption of neurotransmission and neuronal death. Leaking red blood cells release hemoglobin, which directly causes ROS production, lipid superoxide, and neuronal death.[/FONT][/SIZE][/FONT]References:[/FONT]Olszewski J. The Blood-Brain Barrier. Lancet. 1960, 318(8246):584-585.Alluri H, Wiggins-Dohlvik K, Davis M L, et al. Blood-brain barrier dysfunction following traumatic brain injury. Metabolic Brain Disease. 2015, 30(5):1093-1104.Weiss N, Miller F, Cazaubon S, et al. The blood-brain barrier in brain homeostasis and neurological diseases. BBA Ãââ Biomembranes. 2009, 1788(4):842-857.AndrÃÂs I E, Toborek M. Extracellular vesicles of the blood-brain barrier. Tissue Barriers. 2016, 4(1)Serlin Y, Shelef I, Knyazer B, et al. Anatomy and physiology of the blood-brain barrie. Seminars in Cell & Developmental Biology. 2015, 38(9): 2-6.[/FONT] https://www.friendbookmark.com/blogpost/30924/monocyte-chemotactic-protein-1-signaling-pathwayMonocyte chemotactic protein-1 overview[/FONT]Chemokines include a large class of cytokine chemotaxis content, monocyte chemotactic protein-1 (MCP-1), also known as chemokine ligand 2 (CCL2), belonging to the chemokine family CC subclass. In the family, MCP-1 is a major chemotactic and activating factor of inflammation-associated cells such as monocytes/macrophages and is capable of inducing expression of chemokine receptor 2 (CCR2) in a variety of cells. When MCP-1 binds to CCR2, it directly activates monocytes and other immune cells, such as memory T lymphocytes and natural killer cells, to promote inflammation. MCP-1 also induces the expression of adhesion molecules and interleukin-1 (IL-1), IL-6, tumor necrosis factor-ÃÂ (TNF-ÃÂ) and other by activating various intracellular signal transduction pathways. The factor, which causes basophils and mast cells to release histamine, regulates the phagocytic function and pro-apoptotic effect of mononuclear macrophages, and participates in inflammatory diseases and neovascularization and damage repair. MCP-1 recruits and activates inflammatory cells, and activated macrophages secrete profibrotic factors such as transforming growth factor-ÃÂ1 (TGF-ÃÂ1), platelet-derived growth factor (PDGF), and plasma plasminogen activator inhibitors. 1 (PAI-1), matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase-1 (TIMP-1), induce fibroblasts into differentiate myofibroblasts, which play a role in interstitial fibrosis. In addition to chemotactic mononuclear/macrophage-like inflammation-related cells, MCP-1 also affects T cell proliferation and immune function. MCP-1 activates monocytes/macrophages, activated monocytes/macrophages and secrete IL-12, induces initial CD4+ T cells into differentiate Th1 cells, and Th1 cells produce IL-2, gamma interferon (IFN-ÃÂ) and TNFÃÂ, thus positive feedback enhances cellular immunity and macrophage function; Th2 cells produce IL-4 and IL-10, inhibit Th1 cell response, and inhibit macrophage activation. Karpus found that MCP-1 can directly activate IL-4 promoter, make IL-4 expressing cells increased, so that naive T cells differentiate into Th2 cells, thereby enhancing the type 2 immune response. In addition, MCP-1 can also affect the differentiation of neutrophils. Recent studies have found that MCP-1 plays an important role in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, multiple sclerosis and inflammatory bowel disease.[/FONT][/SIZE][/FONT]Monocyte chemotactic protein-1 family[/FONT]Human mcp-1 gene is located on the long arm of chromosome 17 (17q11. 2-q21. 1), it consists of three exons and two introns. This gene encodes a MCP-1 precursor molecule containing 99 amino acids and is modified by shear to become a mature molecule containing 76 amino acids. Two intrachain disulfide bonds are formed between the four cysteines in the MCP-1 mature molecule, and these two adjacent highly conserved disulfide bonds may play an important role in the biological activity of MCP-1. The N-terminus of the MCP-1 molecule binds to the receptor and exerts biological activity, while the MCP-1 mutant the N-terminus can become an inhibitor of MCP-1, thereby blocking the downstream signaling pathway and completely inhibiting MCP-1, so the N-terminus may be its chemotactic functional region. In addition, mutations in certain amino acids such as Lys37, Lys38, Arg24, Tyr28, etc. in MCP-1 molecules may also affect their binding to receptors, causing changes in signaling pathways.[/FONT][/SIZE][/FONT]Monocyte chemotactic protein-1 signaling pathway[/FONT]Monocyte chemotactic protein-1 signaling pathway cascade[/FONT]MCP-1 can activate monocyte-injured renal parenchyma and induce the secretion of various cytokines and growth factor by binding to the receptor CCR2, allowing proliferation of epithelial cells, endothelial cells, and vascular smooth muscle cells, resulting in inflammation. The reaction changes to interstitial fibrosis, which ultimately leads to renal interstitial fibrosis. MCP-1 gene transcription require activation or binding of NF-ÃÂB and AP-1, thereby activating downstream signal transduction pathways. MCP-1 recruits mononuclear/macrophages and stimulates interstitial fibroblasts, which promote extracellular matrix protein deposition, leading to interstitial fibrosis. MCP-1 up-regulates TGF-ÃÂ and matrix metalloenzyme inhibitors by increasing lymphocyte infiltration and interaction with fibroblast/fibroblasts (TIMP1), which ultimately leads to fibrosis of the intestinal wall.[/FONT]Pathway regulation[/FONT]The role of MCP-1 in ATH inflammatory response and the distribution and function of VSMCs in ET1-specific ETAR suggest that ET1 may also be another important stimulator of MCP-1 activation in VSMCs during ATH vascular inflammation. The experiment confirmed that ET1 can induce the expression of MCP-1 protein and mRNA in rat VSMCs. BQ123 ETAR inhibitor significantly inhibited this effect of ET1, and inhibition of BQ788 ETBR inhibitor is not obvious, suggesting ET1 induced MCP-1 in VSMCs produce primarily mediated by ETAR on VSMCs. Further, antioxidants NAC, ERK, p38MAPK and NF-ÃÂB inhibitors PD98059, SB203580 and PDTC also inhibited the expression of MCP-1 protein and mRNA in VSMCs under ET1 stimulation conditions, suggesting that ROS, ERK, p38MAPK and NF-ÃÂB may be involved in ET1-induction VSMCs produce MCP-1 signal transduction pathway. Meanwhile, BQ123 NAC and PD98059 or SB203580 can respectively inhibit the phosphorylation of ERK and p38MAPK in the cytoplasm of VSMCs under ET1 stimulation, further proving that ETAR ROS and MAPK signal molecules (ERK p38MAPK) are important signal molecules in the MCP-1 signal pathway induced by ET1. In summary, vasoactive peptide ET1 can induce MCP-1 production in VSMCs via ROS and MAPK signaling pathways, suggesting that ET1ÃââETARÃââROSÃââMAPKÃââNF-ÃÂBÃââMCP-1 may be involved in the activation of VSMCs during ATH. This will provide a new theoretical basis and therapeutic target for the clinical prevention and treatment of ATH. However, the detailed signal transduction mechanism of this pathway and its relationship with other inflammatory need further study. The study found that in the demyelinating lesions of patients with multiple sclerosis, there are many monocyte-derived macrophages, which secrete inflammatory mediators and promote the progression of MS. As a monocyte chemotactic protein, MCP-1 can up-regulate the expression of monocytes, microglia, and T cells in the brain, cerebrospinal fluid, and blood of MS patients, and induce mononuclear macrophage infiltration of CNS, EAE. Symptoms and degree of inflammation were positively correlated with MCP-1 expression. Experimental studies have shown that electroacupuncture can inhibit the expression of MCP-1 in rat cervical spinal cord, possibly by down-regulating the chemotaxis of MCP-1 on monocytes and interfering with the exudation of activated macrophages and autoreactive T cells. The mononuclear macrophages and T cells infiltrated in the CNS were significantly reduced, thereby alleviating the symptoms of EAE rats and inhibiting the progression of the disease.[/FONT]Relationship with disease[/FONT]Systemic lupus erythematosus[/FONT]Many studies have shown that the content of MCP-1 is significantly increased in systemic lupus erythematosus lesions. The specific mechanism has been described above. The clinical use of MCP-1 inhibitors or other methods to reduce MCP-1 content can effectively alleviate systemic lupus erythematosus.Type 1 diabetes (T1DM)T1DM is an organ-specific autoimmune disease, mainly characterized by dysfunction of glucose metabolism caused by destruction of islet ÃÂ cells, which is genetically predisposed and can be associated with various acute and chronic complications. High levels of MCP-1 observed during islet inflammation.[/FONT][/SIZE][/FONT]References:[/FONT]Lin J, Kakkar V, Lu X. Impact of MCP-1 in atherosclerosis. Current Pharmaceutical Design. 2013, 20(28)Bishayi B, Bandyopadhyay D, Majhi A, et al. Effect of exogenous MCP-1 on TLR-2 neutralized murine macrophages and possible mechanisms of CCR-2/TLR-2 and MCP-1 signalling during Staphylococcus aureus infection. Immunobiology. 2015, 220(3):350-362.Panee J. Monocyte Chemoattractant Protein 1 (MCP-1) in Obesity and Diabetes. Cytokine. 2012, 60(1):1-12.Deshmane S L, Kremlev S, Amini S, et al. Monocyte chemoattractant protein-1 (MCP-1): an overview. J Interferon Cytokine Res. 2009, 29(6):313-326.Hildebrand D G, Alexander E, HÃÂrber S, et al. IÃÂBÃÂ is a transcriptional key regulator of CCL2/MCP-1. Journal of Immunology. 2013, 190(9):4812-4820.[/SIZE][/FONT] https://www.friendbookmark.com/blogpost/30922/polyclonal-vs-monoclonal-antibodies-protocolWhat Is the Difference Between Polyclonal and Monoclonal Antibodies?[/FONT]Antibodies, also known as immunoglobulins, are secreted by B cells (plasma cells) to neutralize antigens such as bacteria and viruses. The classical representation of an antibody is a Y-shaped molecule composed of four polypeptides-two heavy chains and two light chains. Each tip of the "Y" contains a paratope (a structure analogous to a lock) that is specific for one particular epitope (similarly analogous to a key) on an antigen, allowing these two structures to bind together with precision. The ability of binding to an antigen has led to their ubiquitous use in a variety of life science and medical science. These antibodies can be classified into two primary types (monoclonal and polyclonal) by the means in which they are created from lymphocytes. Each of them has important role in the immune system, diagnostic exams, and treatments.[/FONT]This overview will describe the synthesis of monoclonal and polyclonal antibodies, their differentiating properties, and their role in clinical diagnostics and therapeutics.[/FONT][IMG]https://www.creative-diagnostics.com/upload/image/Polyclonal-vs-Monoclona-Antibodies-1.jpg" width="400" height="317" alt="The structure of the antibody" style="box-sizing: border-box; border: 0px; vertical-align: middle; display: block; max-width: 100%; height: auto; margin: auto auto 15px;[/IMG]Fig 1. The structure of the antibody[/FONT][/SIZE][/FONT]Polyclonal vs. Monoclonal Antibodies: Production.[/FONT]Polyclonal antibodies (pAbs) are mixture of heterogeneous which are usually produced by different B cell clones in the body. They can recognize and bind to many different epitopes of a single antigen.[/FONT]Polyclonal antibodies are produced by injecting an immunogen into an animal. After being injected with a specific antigen to elicit a primary immune response, the animal is given a secondary even tertiary immunization to produce higher titers of antibodies against the particular antigen. After immunization, polyclonal antibodies can be obtained straight from the serum (blood which has had clotting proteins and red blood cells removed) or purified to obtain a solution which is free from other serum proteins.[/FONT][IMG]https://www.creative-diagnostics.com/upload/image/Polyclonal-vs-Monoclona-Antibodies-2.jpg" width="450" height="371" alt="The process to generate the polyclonal antibody" style="box-sizing: border-box; border: 0px; vertical-align: middle; display: block; max-width: 100%; height: auto; margin: auto auto 15px;[/IMG]Fig 2. The process to generate the polyclonal antibody[/FONT]Monoclonal antibodies (mAbs) are generated by identical B cells which are clones from a single parent cell. This means that the monoclonal antibodies have monovalent affinity and only recognize the same epitope of an antigen.[/FONT]Unlike polyclonal antibodies, which are produced in live animals, monoclonal antibodies are produced ex vivo using tissue-culture techniques. The process begins with an injection of the desired antigen into an animal, often a mouse, multiple times. Once the animal develops an immune response, the B-lymphocytes are isolated from the animal's spleen and fused with a myeloma cell line, creating immortalized B cell-myeloma hybridomas. The hybridomas, which are able to grow continuously in culture while producing antibodies, are then screened for desired mAb.[/FONT][IMG]https://www.creative-diagnostics.com/upload/image/Polyclonal-vs-Monoclona-Antibodies-3.jpg" width="580" height="611" alt="The process to generate the monoclonal antibody" style="box-sizing: border-box; border: 0px; vertical-align: middle; display: block; max-width: 100%; height: auto; margin: auto auto 15px;[/IMG]Fig 3. The process to generate the monoclonal antibody[/FONT][/SIZE][/FONT]Polyclonal Antibodies vs. Monoclonal Antibodies: Advantages and Disadvantages[/FONT]Both polyclonal and monoclonal antibodies have their own advantages and disadvantages which make them useful for different applications.[/FONT][IMG]https://www.creative-diagnostics.com/upload/image/Polyclonal-vs-Monoclona-Antibodies-4.jpg" width="490" height="198" alt="The specificity of polyclonal antibodies and monoclonal antibodies" style="box-sizing: border-box; border: 0px; vertical-align: middle; display: block; max-width: 100%; height: auto; margin: auto auto 15px;[/IMG]Fig 4. The specificity of polyclonal antibodies and monoclonal antibodies[/FONT]Polyclonal Antibodies[/FONT][/SIZE][/FONT]The advantages and disadvantages of polyclonal antibodies were mainly determined by their multi-epitope specificity. The key advantages and disadvantages are listed below:[/FONT]Advantages:[/FONT]Short production time and low cost.Highly stable and tolerant of pH or buffer changes.High affinity. Since the antibodies bind to more than one epitope, they can help amplify the signal from target protein even with low expression level. This makes these antibodies ideal for immunoprecipitation and chromatin immunoprecipitation.Tolerant of minor changes of antigen. Polyclonal antibodies are less sensitive to antigen changes (slight denaturation, polymorphism, heterogeneity of glycosylation) than monoclonal antibodies.Disadvantages:[/FONT]Prone to batch to batch variability.Multiple epitopes make it important to check immunogen sequence for any cross-reactivity.Monoclonal Antibodies[/FONT][/SIZE][/FONT]The advantages and disadvantages of monoclonal antibodies were mainly based on their high specificity to the same epitope of an antigen. The key advantages and disadvantages are listed below:[/FONT]Advantages:[/FONT]Highly specific recognition of only one epitope of an antigenImmortal hybridoma cell lines have the ability to produce unlimited quantities of antibodiesHigh consistency among experimentsMinimal background noise and cross-reactivityExcellent for affinity purificationDisadvantages:[/FONT]Developing a monoclonal takes time and requires high technical skills.They can produce large amounts of specific antibodies but may be too specific to detect in across a range of species.Vulnerable to the change of epitope. Even a slight change in conformation may lead to dramatically reduced binding capacity.[/SIZE][/FONT]Polyclonal Antibodies vs. Monoclonal Antibodies: Diagnostic Studies[/FONT]Which is better, a monoclonal or a polyclonal antibody? It depends on the different characteristics of monoclonal and polyclonal antibodies.[/FONT]Polyclonal antibodies are ideal reagents in diagnostic assays and hemagglutination reactions due to their ability to recognize different epitopes of a target molecule. The best use of polyclonal antibodies is to detect unknown antigens. Polyclonal antibodies are used as a secondary antibody in immunoassays (e.g. ELISA[/FONT], western blotting[/FONT], microarray assays, immunohistochemistry[/FONT], flow cytometry[/FONT]). Their role is to bind to different epitopes and amplify the signal, leading to better detection.[/FONT]Monoclonal antibodies, in contrast, provide an unlimited source of antibody that is homogeneous and, once characterized, predictable in its behavior. Monoclonal antibodies are often used as primary antibodies in immunoassays due to their ability of specifically binding to a single epitope of an antigen. Through the use of clinical application, some of the disadvantages of using each type of antibody has been nullified. Companies can purify polyclonal antibodies to limit the degree of cross-reactivity in their assays. The combination of monoclonal antibodies leads to the capture of multiple epitopes and expanding its' specificity.[/FONT][/SIZE][/FONT]Polyclonal Antibodies vs. Monoclonal Antibodies: Treatment[/FONT]Where monoclonal antibodies have stood out in a clinical setting is their ability to find and target specific molecules. Monoclonal antibodies' Fc regions are initially tagged with markers and are used to discover cellular surface components. This research promotes the monoclonal antibodies used as medicine. OKT3 (also called Muromonab) was first approved by FDA in 1985 as a specific transplant rejection drug for organ transplant patients preventing graft disease. Since then, forty-one other antibodies have been approved by FDA to fight cancers, rheumatoid arthritis, and asthma and other illnesses. Monoclonal antibodies are also being used as vectors to bring drug to the target cell (e.g. a cancerous cell). When the Antibody-drug conjugates meet the target cell, the drug is released and exerts its effect.[/FONT]Polyclonal antibodies, in contrast, are not as adept as monoclonal antibodies at treating cancer cells due to their lack of specificity and a high degree of cross reactivity. Research is showing that polyclonal antibody therapy can be useful in the treatment of some diseases and as an immunosuppressant for transplant patients.[/FONT][/SIZE][/FONT] https://www.friendbookmark.com/blogpost/29946/influenza-a-unraveling-the-mystery-of-h1n1-and-h3n2Influenza A viruses, the culprits of respiratory illness in humans, are a complex and multifaceted group of viruses. Among the numerous subtypes of Influenza A, H1N1 and H3N2 with a notorious history of causing seasonal epidemics and pandemics, demand special attention.Influenza A H1N1, also known as the swine flu, is a formidable subtype of Influenza A virus that made its first appearance... https://www.friendbookmark.com/blogpost/29944/challenges-in-malaria-vaccine-developmentIntroductionMalaria is caused by infection with Plasmodium parasites. Plasmodium belongs to unicellular eukaryote, and the Plasmodium that infects human body mainly comprises 5 kinds: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale and Plasmodium knowlesi. Among them, Plasmodium falciparum and Plasmodium vivax are the most widespread in the global epidemic ar...