1. The Immune System Chapter 8

2. Learning Objectives Understand the basic organization and function of the immune system. Know the relationships among the cells of the immune system. Describe the effects of acute and chronic exercise on leukocytosis and lymphocytosis. Discuss the effects of exercise intensity and duration on the risk of developing an upper respiratory infection. Know the risks associated with exercising with an infection.

3. Your Perspective Do you believe that exercising and being physically fit make you healthier? How do you react to the statement that some coaches are concerned with an increase in numbers of infections among their athletes?  What do you think may be causing this increase in infections?

4. Relationships Among Cells of the Immune System

5. Immune Mechanisms Non-specific immune mechanisms:  First line of defense against disease-causing organisms  Often successful in preventing disease Specific immune mechanisms:  Additional defenses against invading pathogens

6. Components of Non-Specific Immune Mechanisms External mechanisms:  Skin  Digestive tract  Respiratory tract  Urinary tract Protect the body from most invading organisms Internal mechanisms:  Phagocytic cells  Natural killer (NK) cells  Complement proteins  Interferons Designed to destroy pathogens that penetrate first line of defense

7. Phagocytosis by a Neutrophil or Macrophage From Stuart Ira Fox, Human Physiology (1984). Adapted with permission of The McGraw-Hill Companies.

8. Specific Immune Mechanisms Involve production of cells (antibodies) to provide defense against a specific pathogen (antigen) Two general classifications: 1.Humoral immunity 2.Cell-mediated immunity

9. Components of Humoral Immunity B cells Plasma cells Antibodies (immunoglobulins) Memory B cells

10. Role of B Cells in Humoral Immunity Adapted from Principles of Anatomy and Physiology, 4 th Ed., by G. Tortora and N. Anagostakow. (1984). Reprinted with permission of John Wiley and Sons.

11. Antibodies (Immunoglobulins) Estimated 100 million trillion in the human body  Specific to millions of different antigens Specific antibodies work in specific, diverse ways Antibodies do not directly destroy cells  Identify an invading cell  Activate non-specific immune mechanisms Antibody-dependent cell-mediated cytotoxicity (ADCC): A method of cell destruction involving antibodies

12. Components of Cell-Mediated Immunity Class of lymphocytes called T cells Subclassifications:  Killer T cells  Helper T cells  Suppressor T cells  Memory T cells

13. Role of T Cells in Cellular Immunity Adapted from Principles of Anatomy and Physiology, 4 th Ed., by G. Tortora and N. Anagostakow. (1984). Reprinted with permission of John Wiley and Sons.

14. Exercise and Immune Function Exercise results in:  Leukocytosis  Lymphocytosis Exercise has little or no effect on:  Serum immunoglobulin levels  Complement proteins Exercise may have a small increase on interferon.

15. Exercise and Upper Respiratory Infections (URIs) Studies have shown that exercise can lead to an increased risk of developing a URI. Excessive training and competitive events are likely to increase the risk of a URI. Risk may be intensified by:  Excessive training, caloric restriction, dehydration, psychological stress of competition

16. Your Perspective Your younger sister has been training for a big gymnastics competition. She has been training for months, and the big day is only a week away. But she is now developing a URI, and her coach and doctor tell her to take it easy. What do you suggest to her?

17. Exercise, HIV, and AIDS Exercise does not exacerbate the progression of HIV; instead, it may slow progression and delay the onset of AIDS. Aerobic exercise and resistance training can help HIV-infected individuals maintain health.  Moderate aerobic exercise can increase helper T cell and NK cell counts.  Resistance training can help to maintain or increase muscle mass and diminish weight loss.

18. Some Strategies for Reducing the Risk of Illness Allow sufficient time between training sessions for recovery. Avoid extremely long training sessions. Use periodization of training. Vary training so as to avoid training monotony. When increasing training load, do so on hard days and don’t eliminate recovery days. When recovering from overtraining or illness, begin with light training and increase gradually. (continued)

19. More Strategies for Reducing the Risk of Illness Monitor and record mood, fatigue, and muscle soreness; decrease training load if the session seems hard. Keep stresses to a minimum. Get regular, adequate sleep. Get plenty of rest after traveling across time zones. Make sure diet is well balanced and adequate. Consider drinking carbohydrate “sports” drinks before, during, and after prolonged workouts. Discuss vaccinations with coach or doctor.

20. Advice for Exercising with an Infection Exercise tolerance may be reduced during an infection. Exercising with an infection may increase severity/ duration of the illness. Iron supplements should be avoided to limit bacterial infection. Training should be stopped if fever or systemic symptoms are present. Training should be resumed gradually. Infected team members should be isolated as much as possible from the rest of the team.

21. Your Perspective How do you feel about playing on a team with someone with an upper respiratory infection? How do you feel about playing on a team with someone who is HIV positive? Do you feel that teams you play against have an obligation to reveal the health of their team members?

22. Where to Learn More The immune system:  http://www.niaid.nih.gov/topics/immuneSystem/Page s/structureImages.aspx http://www.niaid.nih.gov/topics/immuneSystem/Page s/structureImages.aspx Antibody production:  www.cellsalive.com/antibody.htm www.cellsalive.com/antibody.htm AIDS and HIV information:  www.thebody.com www.thebody.com