Question

1) Individuals who smoke have much higher rates of lung infection. Explain which first-line defenses mechanisms may be impaired by smoking, allowing pathogens to more readily enter the lower respiratory tract.

2) The diagnosis of tuberculosis involves the observation of lung structures called tubercles on an X ray. What immunologic process leads to the formation of tubercles, and what type of immune cells may comprise these lesions?

3) Provide an explanation in support of or refuting the following statement: "Humans would never develop natural immunity to a novel biological agent created in a laboratory."

4) Explain how super-antigens, such as toxic shock syndrome toxin produced by Staphylococcus aureus, often lead to the development of life-threatening symptoms in an infected individual.

Answer 1

1. Tobacco smoke causes severe damage to the lung tissue.
a. It irritates the tender tissue in the bronchioles and air sacs thereby resulting in their damage
b. It causes a reduction in the elasticity of air sacs = Emphysema
c. It causes swelling of bronchial tubes = Chronic bronchitis

Damage to the immune system function: Cilia are small, thin hair-like projections found in the respiratory tract. They exhibit rhythmic waving to clear mucus, dirt, and other pathogens. They are essential for the healthy functioning of the lungs. i.e. they provide a first line of defense against invading pathogens into the respiratory system. Smoking severely damages these cilia. As a result, cilia become less effective in their function leading to respiratory infections such as Pneumonia.