Vaccines

In an enlarged view of a cut section of a small artery, this animation shows a vaccine injection and follows the path of its antigens, initiating the body's development of antibodies.

Vaccinations are injections of antigens into the body. Once the antigens enter the blood, they circulate along with other cells, such B and T cells. B and T cells are white blood cells that help the body defend itself against foreign invaders.

As the antigens invade the body' s tissues, they attract the attention of macrophages. Macrophages are non-specific scavengers, which in this case, engulf the antigens. The macrophages then signal the T cells that antigens are invading. The killer-type of T cells respond by attacking the invading antigen. Finally, the suppressor T cells stop the attack.

After a vaccination, the body will have a memory of an encounter with a potentially dangerous invader for a period of time, and hopefully have a better ability to fight it off if ever exposed to it again in greater numbers.

Reviewed last on: 10/4/2008
Andrew Schriber, MD, FCCP, Specialist in Pulmonary, Critical Care, and Sleep Medicine, Virtua Memorial Hospital, Mount Holly, New Jersey. Review provided by VeriMed Healthcare Network.

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