Antibodies are proteins produced by the immune system in response to foreign substances, such as bacteria and viruses. They recognize and bind to specific antigens on the surface of these invaders, marking them for destruction or neutralization. Antibodies can also be artificially generated through immunization processes using vaccines or other sources of antigens.
The structure of antibodies consists of two heavy chains (or H-chains) and two light chains (or L-chains). The antigen binding region is located at the tip of each H-chain, while the constant regions at the tips interact with other parts of the immune system to activate an attack against foreign invaders. Each antibody has its own unique shape that allows it to specifically recognize a particular antigen molecule.
Antibody molecules can exist free in solution as monomers or form dimers through disulfide bonding between their heavy chains; they may even form larger aggregates called pentamers when more than one monomer binds together. Depending on their biological function, antibodies may also exist attached to cell surfaces or secreted into body fluids like blood serum where they have various roles in defending against pathogens and controlling inflammation responses within our bodies.
There are five main classes of antibodies based on their structural features: IgG, IgM, IgA, IgE and IgD; each class has multiple subtypes which provide different functions within our body’s immune response system. For example, IgG is responsible for opsonization – coating target cells so that phagocytes such as macrophages can easily detect them – while IgM provides protection from bacteria by directly attacking invading microbial organisms via agglutination (clumping together) or complement activation pathways involving C3/C5 convertases which help amplify an innate killing process known as “complement lysis” . Similarly there are many different types specialized for producing allergic reactions including mast cells secreting histamine after recognizing allergens bound by specific allergen-specific Immunoglobulin E (IgE) patterns only present on certain molecules associated with things like dust mites , pollen grains etc.. Additionally some antibodies act upon tumors allowing us greater control over cancerous growths without needing chemotherapy drugs .
Finally it should be noted that artificial manipulation of antibody structure via genetic engineering techniques now allow scientists to create modified versions possessing enhanced properties compared to natural forms due to changes being made at either a gene sequence level during production itself or post synthesis modifications applied afterwards e.g., chemically modifying certain amino acid residues found along its length enabling improved targeting capabilities & increased specificity – ultimately leading towards better diagnostics & treatments available throughout modern medicine today!