When a foreign substance enters the body.
A class of antibodies that cause allergies are allergens. Allergens are a foreign substance that causes an allergic reaction in the body.
Any particle which is consider as a foreign or allian organism by the body are known as antigen and the proteins whcih are formed against them are called antibodies
Antigen is a substance that can induce the generation of antibodies, any substance that can induce immune response. Antibody is a protective protein produced by the body in response to an antigen.
The best answer would be Antibodies; however, these do not chemically "attack" viruses or bacteria. More accurately, antibodies recognize various germs and allow the various cell types of your immune system to attack and destroy these germs directly. For more info on how this works see: http://en.wikipedia.org/wiki/Adaptive_immune_system
No, antibodies are produced by your body to fight infection.
Antibodies
antibodies
Antibodies are produced by specialized white blood cells called B cells. When a foreign substance, like a bacteria or virus, enters the body, B cells are activated to produce antibodies that specifically target and neutralize the invader.
Your body can produce antibodies in response to infections by bacteria, viruses, or other pathogens. It can also produce antibodies in response to allergens or foreign substances introduced into the body, such as through vaccinations or blood transfusions. Autoimmune disorders can also trigger the production of antibodies that mistakenly target healthy cells or tissues.
An antigen stimulates the production of antibodies. These are either naturally acquired, like from mother to baby (via breast feeding and within the womb). Actively acquired, like you get chicken pox (varicella) and your body fights it off, but because your body has seen the virus it now knows how to fight it. There is also Passively Acquired immunities which are acheived via immunizations where a "dead" or small amount of virus is injected into your body so that your immune system can recognize it and know how to fight it if exposed. An antibody is a "memory cell" it identifies and kills the invader that it has seen before. HIV/ AIDS interrupts that process because it enters the nucleus and "takes over" the cells that identify the invaders... it's kind of a "smart virus".
An antigen is a substance that triggers an immune response in the body, by stimulating the production of antibodies. This response helps the body to recognize and destroy harmful pathogens such as bacteria, viruses, or foreign substances.