Antigens and Antibodies Overview

Any substance that can bind to an antibody or T cell receptor

A macromolecule that triggers an adaptive immune response and reacts with the antibodies produced

A small molecule that can bind to an antibody but needs a carrier to stimulate an immune response

The ability of an antibody to bind specifically to its corresponding antigen

The overall strength of binding between an antibody and its antigen, taking into account multiple binding sites

A specific region on an antigen that an antibody recognizes and binds to

The initial exposure to an antigen

The rapid, enhanced immune response after a second exposure to the same antigen

IgA is the second most abundant antibody in the serum and plays a crucial role in mucosal immunity, particularly in the protection of the respiratory, gastrointestinal, and urogenital tracts.

IgA's structure consists of a monomeric form found in serum and a dimeric form, known as secretory IgA (sIgA), found in secretions. This dimeric structure also includes a J chain and a secretory component, crucial for its function.

Secretory IgA (sIgA) is formed when IgA dimers are combined with a J chain and a secretory component. This process occurs within epithelial cells of mucosal tissues and enables sIgA to cross mucosal membranes and reach the lumen, where it protects against pathogens.

IgD is a relatively rare immunoglobulin, primarily found on the surface of mature B cells. Its exact function remains unclear, but it's believed to play a role in B-cell development and activation.

IgE is the least abundant antibody in the serum and is primarily involved in allergic reactions and parasitic infections. IgE binds to mast cells and basophils, triggering their degranulation and release of histamine and other inflammatory mediators in response to allergens.

An antibody class with four subclasses, found in serum and extravascular spaces, known for its ability to cross the placenta and activate complement.

A subclass of IgG, known for its strong ability to activate complement, which helps eliminate pathogens.

An antibody class with two subclasses, primarily found in mucosal secretions, such as saliva and breast milk.

The largest antibody class, found in serum as a pentamer, responsible for early immune responses.

A property of IgG antibodies, allowing them to pass through the placenta from mother to fetus, providing passive immunity to the newborn.

A component of the immune system that helps destroy pathogens by forming a complex with them and activating other immune cells.

A type of cell that releases histamine and other chemicals, involved in allergic reactions and inflammation.

A process in which immune cells engulf and destroy pathogens, aided by antibodies.

Glycoproteins produced by plasma cells in response to an immunogen, acting as antibodies.

The primary function of immunoglobulins is to bind to antigens, neutralize toxins and viruses, and trigger complement activation.

Immunoglobulins are separated into different fractions based on their electrophoretic mobility. They are found within the gamma globulin fraction.

Immunoglobulins are typically heterogeneous, meaning they vary in structure and function. However, myeloma proteins are homogeneous immunoglobulins produced by malignant plasma cells.

Immunoglobulins consist of two types of chains: heavy chains and light chains. Heavy chains determine the class of immunoglobulin, while light chains are either kappa or lambda.

There are five major classes of immunoglobulins: IgM, IgG, IgA, IgD, and IgE. Each class has a different structure and function.

The variable region of an immunoglobulin is responsible for antigen binding, while the constant region determines the effector functions, such as complement activation or interaction with other cells.

The hypervariable regions within the variable region of an immunoglobulin are highly specific to the antigen. These regions are responsible for the diversity of antibody responses.

A complex of genes that encode molecules involved in immune recognition and self-nonself discrimination.

The ability of an antigen to induce an immune response.

The degree to which an antigen is foreign to the host's immune system.

Highly variable regions within the variable domain of an immunoglobulin chain responsible for antigen binding.

The size of the antigen, usually 10,000 molecular weight.

Constant regions of the immunoglobulin molecule that are relatively similar between different antibodies of the same class.

Differences in the constant region of immunoglobulin molecules that determine the antibody's class or isotype.

The chemical composition of the antigen, including its primary, secondary, tertiary, and quaternary structures.

The ability of the antigen to be processed and presented to immune cells.

Variations in the constant region of immunoglobulin molecules that occur between different individuals within a species.

Substances that enhance the immune response to an antigen.

Unique variations in the variable region of an immunoglobulin molecule that are specific to a particular antibody clone.

The initial immune response to an antigen, characterized by a gradual increase in antibody levels over time.

An antigen that directly stimulates B cells without the need for T cell help.

An antigen that requires the help of T cells to stimulate B cells.

The faster and more robust immune response to an antigen upon subsequent encounters.

A theory explaining how the immune system generates a vast repertoire of antibodies specific to diverse antigens.

Substances that bind to the variable beta domain of T cell receptors, causing widespread activation of T cells.

Pathogen-associated molecular patterns, which are molecules found on pathogens that are recognized by pattern recognition receptors.

Pattern recognition receptors, which are receptors on immune cells that recognize PAMPs.

The process of tagging a pathogen for destruction by immune cells.