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Vaccines

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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.

Update Date: 12/3/2012

Updated by: Paula J. Busse, MD, Assistant Professor of Medicine, Division of Clinical Immunology, Mount Sinai School of Medicine, New York, NY, Review provided by VeriMed Healthcare Network.

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