Antibody

antibodiesimmunoglobulinimmunoglobulinsimmunoglobinvariable regionIgconstant regionimmune globulinimmunoglobulin variable regionvariable domain
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses.wikipedia
2,349 Related Articles

Plasma cell

plasma cellsplasma B cellplasmablast
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses. Antibodies are secreted by B cells of the adaptive immune system, mostly by differentiated B cells called plasma cells. The BCR is found only on the surface of B cells and facilitates the activation of these cells and their subsequent differentiation into either antibody factories called plasma cells or memory B cells that will survive in the body and remember that same antigen so the B cells can respond faster upon future exposure.
Plasma cells, also called plasma B cells, are white blood cells that originate in the bone marrow and secrete large quantities of proteins called antibodies in response to being presented specific substances called antigens.

Antigen

antigensantigenicantigenic proteins
The antibody recognizes a unique molecule of the pathogen, called an antigen, via the fragment antigen-binding (Fab) variable region.
In immunology, antigens (Ag) are structures (aka substances) specifically bound by antibodies (Ab) or a cell surface version of Ab ~ B cell antigen receptor (BCR).

Fragment crystallizable region

FcFc regionimmunoglobulin fc fragments
The ability of an antibody to communicate with the other components of the immune system is mediated via its Fc region (located at the base of the "Y"), which contains a conserved glycosylation site involved in these interactions.
The fragment crystallizable region (Fc region) is the tail region of an antibody that interacts with cell surface receptors called Fc receptors and some proteins of the complement system.

B-cell receptor

B cell receptorBCRB-cell
Antibodies can occur in two physical forms, a soluble form that is secreted from the cell to be free in the blood plasma, and a membrane-bound form that is attached to the surface of a B cell and is referred to as the B-cell receptor (BCR).
The B-cell receptor (BCR) is composed of immunoglobulin molecules that form a type 1 transmembrane receptor protein usually located on the outer surface of a lymphocyte type known as B cells.

Epitope

epitopesantigenic determinantantigenic determinants
Each tip of the "Y" of an antibody contains a paratope (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.
An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells.

B cell

B cellsB-cellB lymphocytes
Antibodies are secreted by B cells of the adaptive immune system, mostly by differentiated B cells called plasma cells.
They function in the humoral immunity component of the adaptive immune system by secreting antibodies.

Immunoglobulin E

IgEIgE antibodiesImmunoglobulin E (IgE)
For example, IgE is responsible for an allergic response consisting of mast cell degranulation and histamine release. While most of these early studies focused on IgM and IgG, other immunoglobulin isotypes were identified in the 1960s: Thomas Tomasi discovered secretory antibody (IgA); David S. Rowe and John L. Fahey discovered IgD; and Kimishige Ishizaka and Teruko Ishizaka discovered IgE and showed it was a class of antibodies involved in allergic reactions.
Immunoglobulin E (IgE) is a type of antibody (or immunoglobulin (Ig) "isotype") that has only been found in mammals.

Immunoglobulin heavy chain

heavy chainheavy chainsheavy
They are typically made of basic structural units—each with two large heavy chains and two small light chains.
The immunoglobulin heavy chain (IgH) is the large polypeptide subunit of an antibody (immunoglobulin).

Immunoglobulin superfamily

Immunoglobulin (Ig) superfamilyimmunoglobulinIg
Antibodies are glycoproteins belonging to the immunoglobulin superfamily.
Molecules are categorized as members of this superfamily based on shared structural features with immunoglobulins (also known as antibodies); they all possess a domain known as an immunoglobulin domain or fold.

Immunoglobulin light chain

light chainlight chainsimmunoglobulin light chains
They are typically made of basic structural units—each with two large heavy chains and two small light chains. A major advance in these structural studies was the discovery in the early 1960s by Gerald Edelman and Joseph Gally of the antibody light chain, and their realization that this protein is the same as the Bence-Jones protein described in 1845 by Henry Bence Jones.
The immunoglobulin light chain is the small polypeptide subunit of an antibody (immunoglobulin).

Antitoxin

antitoxinsantitoxicanti-toxin
The word antibody has formal analogy to the word antitoxin and a similar concept to Immunkörper (immune body in English).
An antitoxin is an antibody with the ability to neutralize a specific toxin.

Blood

human bloodhematologicaloxygen consumption
Soluble antibodies are released into the blood and tissue fluids, as well as many secretions to continue to survey for invading microorganisms.
Most of the proteins remaining are albumin and immunoglobulins.

Isotype (immunology)

isotypeisotypesimmunoglobulin isotypes
The five different types of Fc regions allow antibodies to be grouped into five isotypes.
In immunology, the immunoglobulin (Ig) isotype (class) is encoded by the constant region segments of the immunoglobulin gene which form the Fc (Fragment crystallizable region) portion and the lower segment of the Fab (Fragment antigen-binding) portion of an antibody.

Humoral immunity

humoralhumoral immune responsehumoral response
The production of antibodies is the main function of the humoral immune system.
Humoral immunity or humoural immunity is the aspect of immunity that is mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides.

Gamma globulin

GammaglobulinGamma globulinsgamma-globulins
They constitute most of the gamma globulin fraction of the blood proteins.
The most significant gamma globulins are immunoglobulins (antibodies), although some immunoglobulins are not gamma globulins, and some gamma globulins are not immunoglobulins.

Immunoglobulin A

IgASecretory IgAIgA1
While most of these early studies focused on IgM and IgG, other immunoglobulin isotypes were identified in the 1960s: Thomas Tomasi discovered secretory antibody (IgA); David S. Rowe and John L. Fahey discovered IgD; and Kimishige Ishizaka and Teruko Ishizaka discovered IgE and showed it was a class of antibodies involved in allergic reactions.
Immunoglobulin A (IgA, also referred to as sIgA in its secretory form) is an antibody that plays a crucial role in the immune function of mucous membranes.

Memory B cell

memory B cellsmemory cellsmemory cell
The BCR is found only on the surface of B cells and facilitates the activation of these cells and their subsequent differentiation into either antibody factories called plasma cells or memory B cells that will survive in the body and remember that same antigen so the B cells can respond faster upon future exposure.
Most of these clones differentiate into the plasma cells, also called effector B cells which produce a first wave of protective antibodies and help clear the infection, but a fraction persist as dormant memory cells that survive in the body on a long-term basis after having gone through a highly mutative and selective germinal center reaction.

Gerald Edelman

Gerald M. EdelmanEdelmanGerald Maurice Edelman
A major advance in these structural studies was the discovery in the early 1960s by Gerald Edelman and Joseph Gally of the antibody light chain, and their realization that this protein is the same as the Bence-Jones protein described in 1845 by Henry Bence Jones.
Edelman's Nobel Prize-winning research concerned discovery of the structure of antibody molecules.

Paratope

Each tip of the "Y" of an antibody contains a paratope (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.
A paratope, also called an antigen-binding site, is a part of an antibody which recognizes and binds to an antigen.

Michael Heidelberger

Michael
In the 1920s, Michael Heidelberger and Oswald Avery observed that antigens could be precipitated by antibodies and went on to show that antibodies are made of protein.
He and Oswald Avery showed that the polysaccharides of pneumococcus are antigens, enabling him to show that antibodies are proteins.

Immune system

immuneimmune responseimmune function
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses.
It contains over 20 different proteins and is named for its ability to "complement" the killing of pathogens by antibodies.

Susumu Tonegawa

In a landmark series of experiments beginning in 1976, Susumu Tonegawa showed that genetic material can rearrange itself to form the vast array of available antibodies.
Susumu Tonegawa (利根川 進 Tonegawa Susumu, born September 5, 1939) is a Japanese scientist who was the sole recipient of the Nobel Prize for Physiology or Medicine in 1987, for his discovery of the genetic mechanism that produces antibody diversity.

Immunoglobulin D

IgDimmunoglobulin delta-chainsIgD +
Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually co-expressed with another cell surface antibody called IgM.

Immunoglobulin class switching

class switchingisotype switchingClass switch recombination
Antibody genes also re-organize in a process called class switching that changes the one type of heavy chain Fc fragment to another, creating a different isotype of the antibody that retains the antigen-specific variable region.
Immunoglobulin class switching, also known as isotype switching, isotypic commutation or class-switch recombination (CSR), is a biological mechanism that changes a B cell's production of immunoglobulin from one type to another, such as from the isotype IgM to the isotype IgG.

Immune complex

immune complexesantigen-antibody complexantigen-antibody complexes
Often, once an antibody and antigen bind, they become an immune complex, which functions as a unitary object and can act as an antigen in its own right, being countered by other antibodies.
An immune complex, sometimes called an antigen-antibody complex, is a molecule formed from the integral binding of an antibody to a soluble antigen.