"An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses."
The structure and function of antibodies, including how they recognize and neutralize antigens.
Introduction to Antibodies: An overview of the history and discovery of antibodies, their structure, and their functions in the immune system.
Immunoglobulins and Immunogenetics: A review of the different classes of immunoglobulins (IgG, IgM, IgA, IgD, and IgE) and the genes that encode them.
Antibody Polyclonal and Monoclonal Production: An explanation of the methods used to produce polyclonal and monoclonal antibodies, including immunization and hybridoma technology.
Epitope Recognition: An overview of the process by which antibodies recognize specific antigens on the surface of pathogens and other foreign substances.
Antibody Diversity: An explanation of the mechanisms by which antibodies can generate an enormous diversity of specificities and bind to a wide variety of antigens.
Antibody Affinity and Avidity: A discussion of the factors that influence antibody binding to antigens, including affinity, avidity, and specificity.
Antibody Isotypes and Functions: An overview of the different immunoglobulin isotypes and their roles in immunity, including opsonization, complement activation, and neutralization.
Antibody Engineering: A review of the various methods used to engineer antibodies for drug development and therapeutic applications.
Antibody-Drug Conjugates: An explanation of how antibodies can be conjugated to drugs for targeted delivery to specific cells or tissues.
Antibody-Based Diagnostic Tests: A review of the different types of diagnostic tests that use antibodies, including ELISA, Western blot, and immunohistochemistry.
Immunotherapy: An overview of the use of antibodies as therapeutic agents for the treatment of cancer, autoimmune diseases, and other conditions.
Vaccines and Antibodies: A discussion of the mechanisms by which vaccines stimulate the production of antibodies, including live attenuated, inactivated, and subunit vaccines.
Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC): A review of the role of antibodies in activating and recruiting effector cells to destroy pathogens and infected cells.
Antibody-Dependent Enhancement (ADE): An explanation of how certain antibodies can enhance the entry of pathogens into cells and exacerbate disease.
Complement System: A brief overview of the complement system and how antibodies can trigger complement activation to enhance immunity.
IgA: This type of antibody is found in high concentrations in body fluids such as saliva, tears, and breast milk. IgA is often the first line of defense against infections on the surfaces of the body.
IgD: This type of antibody is found on the surface of B cells (a type of immune cell) and plays a role in activating the immune response.
IgE: This type of antibody is involved in allergic reactions and is often elevated in individuals with allergies or asthma.
IgG: This type of antibody is the most abundant in the blood and is responsible for defending against most bacterial and viral infections. It is also the only type of antibody that can cross the placenta from a mother to her unborn child, providing passive immunity.
IgM: This type of antibody is the first produced by the body during an infection and is often present in high levels in the blood during the acute phase of an infection.
"The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the 'Y' of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision."
"The antibody recognizes a unique molecule of the pathogen, called an antigen."
"Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion)."
"An antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly."
"To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety."
"In mammals, antibodies occur in a few variants, which define the antibody's class or isotype: IgA, IgD, IgE, IgG, and IgM."
"The class hence determines the function triggered by an antibody after binding to an antigen, in addition to some structural features."
"They occur in two forms: one that is attached to a B cell, and the other, a soluble form, that is unattached and found in extracellular fluids such as blood plasma."
"Initially, all antibodies are of the first form, attached to the surface of a B cell – these are then referred to as B-cell receptors (BCR)."
"After an antigen binds to a BCR, the B cell activates to proliferate and differentiate into either plasma cells, which secrete soluble antibodies with the same paratope, or memory B cells, which survive in the body to enable long-lasting immunity to the antigen."
"Soluble antibodies are released into the blood and tissue fluids, as well as many secretions."
"Because these fluids were traditionally known as humors, antibody-mediated immunity is sometimes known as, or considered a part of, humoral immunity."
"The soluble Y-shaped units can occur individually as monomers, or in complexes of two to five units."
"Antibodies are glycoproteins belonging to the immunoglobulin superfamily."
"The terms antibody and immunoglobulin are often used interchangeably, though the term 'antibody' is sometimes reserved for the secreted, soluble form, i.e. excluding B-cell receptors."