Chapter 8 The Immune System

Key Concepts

acquired immune deficiency syndrome (AIDS)acquired immune deficiency syndrome (AIDS) antibodies antibody dependent cell mediated cytotoxicity (ADCC)antibody dependent cell mediated cytotoxicity (ADCC) antigen B cells cell-mediated immunity complement protein systemcomplement protein system helper T cells human immunodeficiency virus (HIV)human immunodeficiency 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)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.Humoral 2.Cell-mediated

In general, how do the specific immune mechanisms work? They produce cells or antibodies that provide 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 usually cause to restrict training or competition, but vigorous exertion should be avoided if there is fever, myalgia, or other symptoms of systemic infection.

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 sessions 3.Use periodization of training 4.Avoid training monotony by ensuring variation in training load 5.When increasing the training load, do so on hard days; don’t eliminate recovery days 6.When recovering from overtraining or illness, begin with light training and increase gradually 7.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 System The Anatomy of the Immune System www-micro.msb.le.ac.uk/MBchB/2b.html Antibody Production Comprehensive AIDS and HIV Information

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.