Stress might actually be beneficial to health

New research has surprisingly shown that stress, generally thought to be bad for the immune system by lowering the body's ability to fight off disease, on a short-term basis might actually be beneficial.

Ohio State University scientist Jacqueline Wiesehan, a graduate student in the laboratory of Dr. John Sheridan at the Ohio State University College of Dentistry has discovered that short-term social stress actually benefited the immune system of mice given low-dose influenza infection, and the scientists believe the finding has broad implications for more effective vaccination strategies.

Previous research and a growing body of literature demonstrates that immune system responsiveness to influenza infection and vaccination is heavily influenced by the nervous system. The mice were subjected to short-term, episodic, and severe stress. They lived in a colony with a well established hierarchy of mice, so having a higher-ranked, more aggressive mouse placed in their cage for two hours was very disruptive and upsetting. This stressful episode was repeated on six consecutive days, after which both stressed and non-stressed mice were given a low-dose influenza infection.

All quickly recovered and within four weeks had developed stable immunological memory to the virus as happens after a flu vaccination. But it was revealed, by delayed hypersensitivity tests and fluorescently-labelled antibody screening, that the mice that had been stressed prior to receiving the influenza infection had a stronger immune reaction to the infection, with markedly higher numbers of two types of T cells specific for influenza. When exposed to the influenza virus a second time, these memory helper T cells (CD4) and cytotoxic T cells (CD8) would allow the body to fight off the virus faster and more successfully.

Dr. Sheridan says that recognising stress as an additional factor that can positively impact on immunity to influenza has broad implications for vaccine development. If the mechanisms through which this stress enhances the immune response can be characterized, it would aid in the development of more effective strategies for vaccination against influenza and possibly other diseases.

Ms. Wiesehan is a graduate student working on a joint DDS/PhD degree in the Ohio State University College of Dentistry. In addition to his appointment in the College of Dentistry's Section of Oral Biology, Dr. Sheridan is also a member of the Department of Molecular Virology, Immunology and Medical Genetics in the College of Medicine and of the Institute for Behavioural Medicine. Other co-authors are Michael Thomas Bailey and David Andrew Padgett, both of The Ohio State University. The study was supported by grants from the National Institutes of Health.

The study was presented at an American Association of Immunologists session during the Experimental Biology meeting in San Diego.