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Body Fluids: Liquid components of living organisms.

Humoral Immune Responses

JoVE 10897

The humoral immune response, also known as the antibody-mediated immune response, targets pathogens circulating in “humors,” or extracellular fluids, such as blood and lymph. Antibodies target invading pathogens for destruction via multiple defense mechanisms, including neutralization, opsonization, and activation of the complement system. Patients that are impaired in the production of antibodies suffer from severe and frequent infections by common pathogens and unusual pathogens. B lymphocytes, also called B cells, detect pathogens in the blood or lymph system. Although B cells originate in the bone marrow, their name is derived from a specialized organ in birds in which B cells were first discovered, the bursa of Fabricius. After release from the bone marrow, B cells mature in secondary lymphoid tissues, such as the spleen, lymph nodes, tonsils and mucosa-associated lymphoid tissue throughout the body. B cells bind to specific parts of a pathogen, called antigens, via their B cell receptors. In addition to antigen binding, B cells require a second signal for activation. This signal can be provided by helper T cells or, in some cases, by the antigen itself. When both stimuli are present, B cells form germinal centers, where they proliferate into plasma cells and memory B cells. All cells that are derived from a common ancestral B c

 Core: Immune System

Antibody Structure

JoVE 10898

Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding.

Antibodies consist of four polypeptide chains: two identical heavy chains of approximately 440 amino acids each, and two identical light chains composed of roughly 220 amino acids each. These chains are arranged in a Y-shaped structure that is held together by a combination of covalent disulfide bonds and noncovalent bonds. Furthermore, most antibodies carry sugar residues. The process of adding sugar side chains to a protein is called glycosylation. Both the light chain and heavy chain contribute to the antigen binding site at each of the tips of the Y structure. These 110-130 amino acids are highly variable to allow recognition of an almost unlimited number of antigens. This region is also called the variable region and is part of the antigen binding fragment. Each arm of the Y-shaped unit carries an identical antigen binding site. Antibodies can crosslink antigens: when one arm binds to one antigen and the other arm binds to a second, structurally identical antigen. Crosslinking is facilitated by the f

 Core: Immune System

Cross-reactivity

JoVE 10900

The ability of a single antibody to recognize multiple structurally similar epitopes is an important immune defense strategy that enables the host to efficiently defend against many potentially threatening pathogens. However, cross-reactivity also elicits allergy symptoms against related allergens. It is increasingly important to understand the principles of cross-reactivity, as antibodies are actively being developed as therapeutic modalities for diverse diseases, including cancer. Antibodies can initiate an immune response by binding to specific structures on the surface of pathogens or other foreign elements. By definition, anything that is bound by an antibody, and subsequently elicits an immune response, is called an antigen. Often, antigens are proteins on the surface of viruses, bacteria, fungi, and protozoan invaders. The specific sequence of amino acids that is recognized by the antibody is called an epitope. Most epitopes are only 5-6 amino acids long. As such, a single antigen may present several distinct epitopes. Cross-reactivity occurs when two distinct epitopes are structurally similar, and hence are recognized by the same antibody. A major benefit of antibody cross-reactivity is that it provides cross-protective immunity to related pathogens. When a circulating antibody recognizes a viral or bacterial pathogen that it has encountered previ

 Core: Immune System

Using a pH Meter

JoVE 5500

Source: Laboratory of Dr. Zhongqi He - United States Department of Agriculture


Acids and bases are substances capable of donating protons (H+) and hydroxide ions (OH-), respectively. They are two extremes that describe chemicals. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither acidic…

 General Chemistry

Generation of Comprehensive Thoracic Oncology Database - Tool for Translational Research

1Pritzker School of Medicine, University of Chicago, 2Department of Medicine, University of Chicago, 3Department of Medicine, Northshore University Health Systems, 4Department of Pathology, University of Chicago, 5Department of Surgery, University of Chicago, 6Department of Biostatistics, University of Chicago

JoVE 2414

 Medicine

High-throughput Parallel Sequencing to Measure Fitness of Leptospira interrogans Transposon Insertion Mutants During Golden Syrian Hamster Infection

1Veterans Affairs Greater Los Angeles Healthcare System, 2Departments of Medicine, David Geffen School of Medicine at University of California Los Angeles, 3Departments of Urology, David Geffen School of Medicine at University of California Los Angeles, 4Departments of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles

JoVE 56442

 Immunology and Infection

Using Nanoplasmon-Enhanced Scattering and Low-Magnification Microscope Imaging to Quantify Tumor-Derived Exosomes

1Department of Integrated Traditional Chinese and Western Medicine, West China Hospital of Sichuan University, 2Virginia G. Piper Biodesign Center for Personalized Diagnostics, The Biodesign Institute, Arizona State University, 3School of Biological and Health Systems Engineering, Arizona State University, 4Department of Electrical and Computer Engineering, North Dakota State University

JoVE 59177

 Bioengineering

A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection

1Breast Surgery Group, Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Queen's Medical Centre, University of Nottingham, 2Medical Microbiology and Immunology Department, Faculty of Medicine, Mansoura University, 3Nottingham Digestive Diseases Centre and NIHR Nottingham Digestive Diseases Biomedical Research Centre, School of Medicine, Queen's Medical Centre, University of Nottingham

JoVE 57399

 Immunology and Infection

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

1School of Public Health of Southeast University, Laboratory of Environment and Biosafety Research Institute of Southeast University in Suzhou, 2Key Laboratory of Child Development and Learning Science (Ministry of Education), School of Biological Science & Medical Engineering, Southeast University, 3School of Public Health, Tianjin Medical University, 4British Columbia Academy, Nanjing Foreign Language School

JoVE 56445

 Chemistry

High-resolution Melting PCR for Complement Receptor 1 Length Polymorphism Genotyping: An Innovative Tool for Alzheimer's Disease Gene Susceptibility Assessment

1Department of Immunology, Reims University Hospitals, Robert Debré Hospital, 2Faculty of Medicine, LRN EA 4682, University of Reims Champagne-Ardenne, 3Department of Internal Medicine and Geriatrics, Reims University Hospitals, Maison Blanche Hospital, 4Faculty of Medicine, EA 3797, University of Reims Champagne-Ardenne

JoVE 56012

 Genetics

Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages

1Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, 2German Center for Lung Research, 3Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Center Giessen and Marburg

JoVE 55146

 Immunology and Infection

Establishment of Larval Zebrafish as an Animal Model to Investigate Trypanosoma cruzi Motility In Vivo

1Laboratory of Neurosciences and Circadian Rhythms, School of Medicine, Universidad de los Andes, 2Biophysics Group, Department of Physics, Universidad de los Andes, 3Laboratory of Basic Medical Sciences, School of Medicine, Universidad de los Andes, 4Department of Microbiology and Immunology, University of North Carolina, 5Notre Dame Initiative for Global Development, University of Notre Dame, 6USAID Research and Innovation Fellowship program

JoVE 56238

 Developmental Biology

Circulating MicroRNA Quantification Using DNA-binding Dye Chemistry and Droplet Digital PCR

1Department of Experimental, Diagnostic and Specialty Medicine - DIMES, University of Bologna, 2Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, 3Department of Life Sciences and Biotechnology, University of Ferrara, 4Department of Morphology, Surgery and Experimental Medicine and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara

JoVE 54102

 Bioengineering

Quantitative Mass Spectrometric Profiling of Cancer-cell Proteomes Derived From Liquid and Solid Tumors

1Institute of Pathology, University Medical Center, Göttingen, 2Department of Hematology/Oncology, Goethe University of Frankfurt, 3Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 4Bioanalytics, Institute of Clinical Chemistry, University Medical Center, Göttingen, 5German Cancer Consortium, 6German Cancer Research Center

JoVE 52435

 Medicine
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