Chapter 8

The Immune System

Key Concepts

• acquired immune deficiency syndrome (AIDS)

• antibodies• antibody dependent cell

mediated cytotoxicity (ADCC)

• antigen• B cells• cell-mediated immunity

• complement protein system

• helper T cells• human immuno

deficiency virus (HIV)

• humoral immunity

• immunoglobulins

• interferons

• killer T cells• leukocytes• leukocytosis• lymphocytes• lymphocytosis• macrophages• memory B cells• memory T cells

• monocytes• natural killer (NK)

cells• neutrophils• Phagocytosis• plasma cells• suppressor T cells• T cells• upper respiratory

infection (URI)

Review Questions

What is the difference between the two general classifications of the immune system?

The specific immune system provides a defense

against a specific pathogen, while the non-

specific immune system does not provide a

specific defense against a specific pathogen.

What are the components of non-specific immunity?

• External mechanisms, such as– Skin– Digestive tract– Respiratory tract– Urinary tract

• Internal mechanisms, such as– Phagocytic cells– NK cells– Complement proteins– Inteferons

What are the two classifications of the specific immune mechanisms?

1. Humoral2. Cell-mediated

In general, how do the specific immune mechanisms work?

They produce cells or antibodies thatprovide a defense against antigens.

What are the four components of humoral immunity?

• B cells• Plasma cells• Antibodies• Memory B cells

What are the components of cell-mediated immunity?

• T cells, which give rise to:– Killer T cells– Helper T cells– Suppressor T cells– Memory T cells

Exercise alters several components of the immune function. What are they and what effect does exercise have?

• Exercise results in leukocytosis• Exercise results in lymphocytosis• Exercise may increase interferon

levels, but the significance is unknown

Name some reasons why HIV positive individuals should exercise. Why?

• Exercise does not exacerbate the progression of HIV and may slow it.

• Moderate aerobic exercise can increase helper T cell and NK cell counts.

• Resistance training can help to maintain or increase muscle mass and so diminish the weight loss characteristic of stages 2 and 3 of HIV infection.

Should athletes train during infections?

Mild upper respiratory infections are not usuallycause to restrict training or competition, butvigorous exertion should be avoided if there isfever, myalgia, or other symptoms of systemicinfection.

Name some strategies that can help athletes minimize the risk of becoming ill?

1. Allow sufficient time between training sessions for recovery

2. Avoid extremely long training sessions3. Use periodization of training4. Avoid training monotony by ensuring variation in

training load5. When increasing the training load, do so on hard

days; don’t eliminate recovery days6. When recovering from overtraining or illness, begin

with light training and increase gradually7. Monitor and record mood, feelings of fatigue, and

muscle soreness; decrease the training load if the session seems harder than usual

Name some strategies that can help athletes minimize the risk of becoming ill? (continued)

8. Keep other stresses to a minimum

9. Get regular and adequate sleep

10. Get more rest after travel across time zones

11. Pay attention to diet and make sure it is well balanced

12. Ensure adequate total dietary intake

13. Consider drinking carbohydrate sports drinks before, during, and after prolonged workouts

14. Consider the timing of vaccinations

What are some guidelines for considering the appropriateness of training and competition during infection?• Exercise tolerance may be reduced

• Exercising with an infection may increase the severity and duration of the illness

• Light exercise during convalescence may enhance recovery

• Training should be stopped if fever or systemic symptoms are present

• Training should be resumed gradually• Infected team members should be isolated

Useful Websites

Immune Systemwww.niaid.nih.gov/final/immun/immun.htm

The Anatomy of the Immune Systemwww-micro.msb.le.ac.uk/MBchB/2b.html

Antibody Productionwww.cellsalive.com/antibody.htm

Comprehensive AIDS and HIV Informationwww.thebody.com

Selected Images

Figure 8.2 Phagocytosis by a neutrophil or macrophage.

Figure 8.3 Role of B cells in humoral immunity.

Figure 8.4 Role of T cells in cellular immunity.