How Does the Body Defend Itself When Harmful Bacteria Gets Inside?

The body defends itself from bacteria by triggering an immune system response. The immune system is a collaboration of cells and organs that work together to remove bacteria, viruses and other foreign organisms that may get inside the body. The common response to harmful bacteria is the release of B cells, T cells, phagocytes and inflammation.

B Cells

• Lymphocytes are a type of white blood cell. These cells fights and guard against potentially infectious bacteria. B cells, a type of lymphocyte, destroy bacteria by producing antibodies. Antibodies recognize and deactivate foreign bodies (antigens).The specific antibodies produced continue to exist after an infection, protecting against future invasions. If the same bacteria attack again, the body will respond quicker, reducing the chances of infection. The body may also produce antibodies due to immunizations. Immunizations are antibodies introduced into a person's system.

T Cells

• T cells are activated when the cell's receptor senses antigen fragments or cancerous cells. Also a lymphocyte, T cells work by destroying harmful bacteria directly. These cells also work by regulating the immune system by releasing cytokines. Cytokines are chemical messengers that are capable of stimulating B cells, phagocytes and other cells that regulate the immune system.

Phagocytes

• When harmful bacteria enter the body, the body secretes white blood cells called phagocytes, a cell that attaches then digests foreign bodies like bacteria. Several cells fall under the phagocyte umbrella. Neutrophils are the body's primary phagocyte. These cells contain chemicals that dissolve harmful bacteria. Physicians often order a white blood cell count to look for phagocytes and other white blood cells. These tests determine a body's response to an infection.

Inflammation

• The body also inflames in response to harmful bacteria. Inflammation not only occurs when bacteria invades the body, but also when the tissues are damaged in response to situations like heat, toxins and trauma. Inflammation isolates harmful bacteria by causing swelling, preventing bacteria from invading nearby tissues. Another inflammatory response is the release of chemicals like prostaglandins and histamines. These chemical responses trigger phagocytes to remove foreign bodies as well as remove damaged cells.

Antibiotics

• If the immune system fails to counter an infection caused by harmful bacteria, a health care provider may prescribe antibiotics. Antibiotics kill bacteria. Some antibiotics, like penicillin, work by directly destroying bacteria in the body. Antibiotics such as tetracycline prevent harmful bacteria from multiplying. This type of antibiotic controls bacteria growth, giving the immune system time to form an attack against harmful bacteria.