Introduction to the Immune System

Question 1

What are the functions of the complement system?

Answer 1

Lysis

Chemotaxis

Opsonization

Question 2

Name some structures or characteristics that make up the innate immune system.

Answer 2

• Skin
• Mucous membranes
• Normal flora
• Stomach acid
• pH
• Complement system

Question 3

What bacteria are more susceptible to the effects of the complement system?

Answer 3

Gram-negative bacteria - Lack thick peptidoglycan cell wall

Question 4

What cells serve as primary phagocytes?

Answer 4

• Neutrophils - shorter lived
• Macrophages - also secrete proteins called cytokines to alert other cells

Question 5

What is chemotaxis?

Answer 5

Movement of a cell in the direction corresponding to a gradient of increasing or decreasing concentration of a chemical. Chemokines are cytokines that serve as chemoattractant guides.

Question 6

Phagocytes are non-specific in their immune response. How do they identify pathogens in the body?

Answer 6

Patter recognizing receptors (PRRs) on phagocytes recognize PAMPS on pathogens.

Question 7

What immune cells process and present antigens to lymphocytes?

Answer 7

Antigen-presenting cells (APCs)

Question 8

What cells can serve an antigen-presenting function?

Answer 8

• Neutrophils
• Macrophages
• Dendritic Cells (best APCs)

Question 9

What group of cells plays a major function in adaptive immune response? What cells belong to this group?

Answer 9

Lymphocytes

• B cell
• CD8 (Cytotoxic) T Cell
• CD4 (Helper) T Cell
• Regulatory T Cell

Question 10

What are the functions of T cells?

Answer 10

Produce cytokines

Kill infected cells

Activate B cells

Question 11

What are the functions of B cells?

Answer 11

Produce antibodies

Opsonize the pathogen

Question 12

What are the differences btween humoral and cell-mediated immunity?

Answer 12

Humoral immunity consists of B cells and their antibodies that are present in body fluids. Cell-mediated immunity refers to T cells that actively eliminate pathogens and kill infected cells.

Question 13

This term refers to the immune system’s first exposure to an antigen by naive lymphocytes.

Answer 13

Primary immune response

Question 14

The secondary immune response refers to what encounter with a pathogen.

Answer 14

Any subsequent encounter with a pathogen following the primary immune response.

Question 15

What is the final step in the immune response following exposure to a pathogen.

Answer 15

Retraction of the immune response by regulatory T cells - chronic immune response and inflammation is detrimental to the body

Question 16

Compare and contrast the innate and adaptive immune system responses.

Answer 16

Innate Response - Immediate/quick non-specific response. There is no memory.

Adaptive Response - Delayed/slow, but highly specific response activate by exposure to an antigen. Memory of the pathogen for quicker future response.