HOw Vaccination Works
Vaccines help develop immunity by imitating an infection by either using a weakened version of the virus a relative (eg. cowpox for smallpox) or the viron's shell hence that's all the immune system needs to recognise the virus . This type of infection, however, does not cause illness, but it does cause the immune system to produce T-lymphocytes and antibodies. Once the imitation infection goes away, the body is left with a supply of B-lymphocytes that will remember how to fight that disease in the future
T-lymphocytes
T cells do not recognize free-floating antigens. Instead , their surfaces contain specialized antibody-like receptors that see fragments of antigens on the surfaces of infected or cancerous cells. T cells contribute to immune defenses in two major ways: Some direct and regulate immune responses, whereas others directly attack infected or cancerous cells.
B-lymphocytes
B-lymphocytes cells work chiefly by secreting substances called antibodies into the body’s fluids. Antibodies ambush foreign antigens circulating in the bloodstream. They are powerless, however, to penetrate cells