Lecture 6: Immune Response

Question 1

What are the 3 layers of immunity?

Answer 1

• barrier defenses -> prevent infection
• innate immunity -> non-specific response
• adaptive immunity -> specific to foreign invader

Question 2

What is not a barrier defense?

Answer 2

fever

Question 3

Where are innate responses involved?

Answer 3

• phagocytosis
• recycling of organelles & worn out native cells
• lysosomal activity
• in monocytes, neutrophils, & eosinophils
• macrophages & dendriti cells

Question 4

What are natural killer cells?

Answer 4

• non-specific lymphocytes
• trigger apoptosis in bacteria, tumor cells, & cells infected by viruses
• release perforins & granzymes to destroy cells

Question 5

What is inflammation?

Answer 5

• activates mast cells, basophils, & macrophages
• release of cytokines that attract other immune cells

Question 6

What do basophils & mast cells release that act as vasodilators?

Answer 6

histamines & prostaglandins

Question 7

Why does a fever cause a systemic increase in temperature?

Answer 7

• activating native immune cells
• inhibiting enzymes in bacterial cells & viruses
• increasing ATP production
• promoting increased O2 distribution

Question 8

What are the characteristics of MHC class 1 molecules?

Answer 8

• present native cystolic peptides
• permits presentation of antigens from viruses/ abnormal cancer cells
• stimulates CD8+ T cells

Question 9

In immunity, what destroys the organelles?

Answer 9

granzymes

Question 10

What are the characteristics of MHC class 2 molecules?

Answer 10

• found in phagocytic cells (macrophages, dendritic cells, B cells)
• transport antigens to cell surface using MHC proteins
• stimulate CD4+ cells

Question 11

What is the role of type 1 helper T cells?

Answer 11

1. binds to MHC ons surface
2. learn identity of foreign invaders
3. activate macrophages cytotoxic T cells
4. teach identity to cytotoxic cells

Question 12

What is the role of type 2 helper T cells?

Answer 12

1. activate B cells
2. B cells trigger clonal expansion (mitosis)

Question 13

What happens to B cells when activated by type 2 helper T cells?

Answer 13

• become memory B cells for future defense
• become plasma cells to produce antibodies

Question 14

What are the 3 ways antibodies may act?

Answer 14

1. bind to antigens on pathogens to neutralize them
2. mark pathogens for phagocytosis (opsonization)
3. target pathogens for destruction using similar system to natural killer cells (complementation)
4. glutonation -> antibodies bind several cells at once to make it easier to destroy