S3L2 - Recognition Phase

Question 1

What triggers an immune response?

Answer 1

An antigen presenting cell detecting foreign antigens, then processing the pathogen to present it to T cells.

Question 2

Why aren’t cancer cells destroyed by immune system?

Answer 2

Cancer cells emit a signal that deactivates T cells

Question 3

What ar the different forms of antigen presenting cells?

Answer 3

1. Dendritic and langerhans cells
   - Both present antigens to naive T cells, causing a T cell response against most pathogens
2. Macrophages and B cells - present pathogen to effector T cells
   - Macrophages act to increased phagocytic activities.
   - B cells trigger an antibody response (humoral response)

Question 4

What is the difference between Naiive and effector T cells?

Answer 4

Naiive T cells= have not previously encountered the antigen

Effector T cells = have previously encountered the antigen and are capable of performing effector functions during an immune response.

Question 5

What are immunoglobins?

Answer 5

Immunoglobins are antibodies in the blood. They are proteins made by the immune system to fight antigens. Immunoglobins have specificity and are only effective against a specific antigen.

Question 6

What are the 5 different subclasses of immunoglobins?

Answer 6

IgA = high concentration in mucous membranes, as well as in saliva and tears.

IgG = Most abundant. Found in all body fluid and protects against bacterial and viral infections

IgM = Found mainly in blood and lymph fluid, is the first antibody to be made by the body to fight a new infection.

IgE = Mainly associated with allergic reactions ( immune system overreacts to environmental antigens such as pollen or pet dander ). Found in lungs, skin and mucous membranes.

IgD = exists in small amounts in the blood, least understood antibody.