Immune System Health Article

T cells

T-cell lymphocytes are the primary players in the cell-mediated response. When an antigen-specific helper T cell is activated, the cell multiplies. The cells produced from this division are called cytotoxic T cells. Cytotoxic T cells target and kill cells that have been infected with a specific microorganism. After the infection has subsided, a few memory T cells persist, so conferring immunity.

Chemical signals activate the immune response; likewise, chemical signals must turn it off. When all the invading microorganisms have been neutralized, special T cells (called suppressor T cells) release cytokines that deactivate the cytotoxic T cells and the plasma cells, and the cells of the body return to normal functioning.

Sudden Infant Death Syndrome

In 1994, researchers reported in the medical journal The Lancet that abnormal immune response in the respiratory system may contribute to sudden infant death syndrome (SIDS). Two to three times as many T-lymphocytes were found in lungs of children who died from SIDS that in those who died from other causes. In addition, the number of B-lymphocytes appears to be higher in SIDS infants than in others.

The World Resources Institute in Washington, DC, issued a report in 1996 linking the increased exposure to chemical pesticides in the environment and immune system disorders. Developing nations are at the greatest risk, since they often do not regulate pesticide use. The Institute cited the former Soviet republic of Moldova, where, from 1960 to the late 1980s, pesticides were used in concentrations nearly 20 times the average used elsewhere in the world. Eighty percent of children known to have been exposed to the pesticides appear to have irregularities in their immune systems. Because the interpretation of the study results is difficult, more research is needed.

Books

Almonte, Paul. The Immune System. Crest wood House; Maxwell Macmillan Canada; Macmillan International, 1991.

Cook, Allan R. Immune System Disorders Sourcebook: Basic Information for the Layperson. Detroit, MI: Omnigraphics, 1996.

Edelson, Edward. The Immune System. New York: Chelsea House, 1989.

Schindler, Lydia Woods. The Immune System: How It Works. Bethesda, MD: U. S. National Institutes of Health, 1993.

Periodicals

Engelhard, Victor H. "How Cells Process Antigens." Scientific American 271, August 1994, p. 54.

Kedzierski, Marie. "Vaccines and Immunisation (sic)." New Scientist 133, February 8, 1992, p. S1.

Kisielow, Pavelrod. "Self-Nonself Discrimination by T Cells." Science 248, June 15, 1990, p. 1369.

Miller, Jacques. "The Thymus: Maestro of the Immune System." BioEssays 16, July 1994, p. 509.

Radesky, Peter. "Of Parasites and Pollens." Discover 14, September 1993, p. 54.

"Special Issue: Life, Death, and the Immune System." Scientific American 269, September 1993.

Strange, Carolyn. "Rethinking Immunity." BioScience 45, November 1995, pp. 663+.

Travis, John. "Tracing the Immune System's Evolutionary History."Science 261, July 9, 1993, p. 164.