Antigen is a immunogenic portion present on the foreign cell or substance. To combat that antigen or foreign cell, our body’s immune system produces antibodies.
Differences between antigen and antibody
|1||Name||Anti – Against|
Gen – Generate/ formation
|Anti – Against|
Body-Against the body
|2||Other names||Also called as Immunogens.||Also called immunoglobulins (Igs).|
|3||Symbols||The antigen can be represented by the “Ag” symbol.||The antibody can be represented by the “Ab” symbol.|
|4||Processing||The antigen will be processed by the Macrophages, Dendritic cells, and B-cells are of|
Antigen Processing cells (APC)
|The Antibody will be processed by the Plasma and Memory B-cells.|
|5||Composition||Antigens are mostly made of proteins but also contain carbohydrates, lipids, or nucleic acids.||Antibodies are made up of only proteins like glycoprotein, lipoprotein, etc.|
|6||Key part in|
|An antigen contains the epitope region. It is the region that attaches to the antibodies.||Antibody contains a paratope region. It is a variable region that|
specifically binds to an epitope.
|7||Role||The antigen plays a role in causing disease or evoking an allergic reaction.||Antibody plays a role in the nullification of pathogens or harmful substances. They|
precipitate the antigenic substance, lyse it or and lead to phagocytosis
|8||Size||The antigen Size varies from one to another; the greater the size of the molecule, the higher|
is its antigenicity.
|The size of immunoglobulin is|
variable according to the type of antibody.
|The structure of the antigen shows great complexity.||The structure of all classes of immunoglobulins is Y-shaped.|
|10||Specificity||The specificity of the antigen depends upon its epitope.||The specificity of the antibody depends on its paratope.|
|11||Foreignness||An antigen from the outside environment is highly antigenic. So it is a foreign substance to the body.||The antibody is produced by our|
body’s immune system.
|12||Types||Antigens are grouped into two divisions|
1) Foreign Antigens: It is also called Heteroantigens, these
antigens present in
bacteria, viruses, snake
2) Self Antigens: It is also called Autoantigens; these antigens are present within the body and lead to autoimmune
|Antibodies are divided into 5 different types|
1) Immunoglobulin G: Most important of all the antibodies. It is present in the bloodstream and other body fluids. The important function is it can cross the placenta.
2) Immunoglobulin A: It plays an important role in
neutralizing the bacteria and virus. It is widely present in respiratory
secretions, saliva, tears, etc.
3) Immunoglobulin M: The function of the IgM is the same as IgG, but it cannot cross the placenta. It is the largest-sized antibody.
4) Immunoglobulin E: It is a secondary antibody. It helps to diagnose allergic-
reaction and diseases.
5) Immunoglobulin D: It is also a secondary antibody. They help in the activation of the B cell for the defense mechanism.
|13||Prevalence||The antigens are found on bacteria, fungi, and viruses and also all different types of cells and biological substances.||The antibodies are produced only by the lymphocytes|
|14||Importance||The antigens help to determine the type of microbe or substance entered into the|
|The antibodies are more|
important to the person to prevent diseases and also kill pathogens and fight diseases.
|15||Features||There are three specific|
features like being
2) Endogenous, and
3) Immunological memory.
4) Immune tolerance.
|16||Functions||The function of the antigens is to trigger the production of the|
|1) They activate the|
complement system is to
destroy the pathogens.
2) Promotes the phagocytosis of foreign substances by neutrophils and macrophages