"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."
Antibodies or immunoglobulins are protein molecules that the immune system produces to recognize and neutralize foreign objects.
Antibodies: The basic function, structure, and types of immunoglobulins. Understanding the different classes of immunoglobulins and their roles in the immune system.
B-cell development: Understanding the processes of B-cell development and differentiation, the role of B-cells in immune response, and how they produce immunoglobulins.
Antigen recognition: Understanding how antigens are recognized by B-cells and how antibody production is triggered.
Immunoglobulin gene rearrangement: Understanding the process of gene rearrangement that occurs during B-cell development and how it contributes to antibody diversity.
Antigen binding: The mechanism of antigen binding and the various factors that contribute to antibody-antigen interactions.
Immunoglobulin structure: Detailed structure of immunoglobulins, including their domains, subunits, and molecular features.
Immunoglobulin isotypes: Understanding the various classes (isotypes) of immunoglobulins and their distribution in different tissues and fluids.
Affinity and avidity: The principles of antibody affinity and avidity and how they contribute to the effectiveness of the immune response.
Antibody-based therapies: Understanding the role of antibodies in therapy and how they are used to treat different diseases.
Autoimmunity and immunodeficiency: The importance of immunoglobulin production in autoimmune and immunodeficiency disorders and the causes and mechanisms behind these conditions.
Immunoglobulin assays: Different methods of measuring immunoglobulin levels and their applications in clinical diagnosis and research.
Monoclonal antibodies: Understanding the production and function of monoclonal antibodies and their applications in research and medicine.
IgA (Immunoglobulin A): This type of immunoglobulin is mainly found in mucosal secretions such as tears, saliva, and breast milk, and helps prevent the attachment of pathogens to the mucosal tissue.
IgD (Immunoglobulin D): IgD is primarily found on the surface of B cells and plays a role in activating B cells.
IgE (Immunoglobulin E): IgE is associated with allergic reactions, and plays an important role in the immune response to parasitic infections.
IgG (Immunoglobulin G): IgG is the most common type of immunoglobulin in the blood, and provides long-term protection against pathogens by activating complement proteins and phagocytes.
IgM (Immunoglobulin M): IgM is the first type of antibody produced in response to an infection, and is best suited for neutralizing pathogens in the blood.
IgG1: This subtype of IgG is the most abundant and important for activating phagocytes and complement proteins.
IgG2: IgG2 is involved in opsonization and neutralization of encapsulated bacteria.
IgG3: IgG3 is the most potent stimulator of complement proteins and is important for the destruction of bloodstream pathogens.
IgG4: IgG4 is thought to play a role in regulating the immune system, and is involved in the suppression of allergic reactions.
IgA1: This subtype of IgA is found in blood, while IgA2 is found in mucosal secretions.
IgG subclasses (IgG1-4): These subtypes of IgG have different functional properties and are important in the immune response to different types of pathogens.
IgM subclasses: There are no known subclasses of IgM.
"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."
"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)."
"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."
"The constant region at the trunk of the antibody includes sites involved in interactions with other components of the immune system."
"In mammals, antibodies occur in a few variants, which define the antibody's class or isotype: IgA, IgD, IgE, IgG, and IgM."
"Antibodies from different classes also differ in where they are released in the body and at what stage of an immune response."
"Together with B and T cells, antibodies comprise the most important part of the adaptive immune system."
"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."
"Antibodies are glycoproteins belonging to the immunoglobulin superfamily."
"The terms antibody and immunoglobulin are often used interchangeably."
"The term 'antibody' is sometimes reserved for the secreted, soluble form, i.e., excluding B-cell receptors."
"An antibody, also known as an immunoglobulin, is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses."
"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."