What is responsible for stimulation the immune system to produce antibodies?

Answer 1

The presence of something that shouldn't be there like bad bacteria, viruses and fungi.

Also your immune system does not only become active when under threat much of it patrols your body keeping you healthy specialised T-cells and B-cells enable you to be immune to things that you have encountered before as they become memory cells keeping lookout for whatever triggered them in the first place and to quickly call for reinforcements should you experience it again.

Other cells such as Destroyer cells are your 1st line of defence which find infected cells kill what's inside by destroying that cell unfortunely they destroy many others nearby creating alot of collateral damage for instance when you have a cold and you get a you get a sore throat that is evidence that your destroyer cells have been hard at work.

Answer 2

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".

Answer 3

the foreign material that stimulates the production of an antibody is an antigen