Intro to Immunology

Question 1

Distinguish the roles of innate and adaptive immunity, including humoral (antibody-mediated) and cell-mediated immune responses

Answer 1

Innate:
- rapid, initial defense
- blocks entry of microbes into tissue
- rapidly eliminates microbes that enter
Adaptive:
- develops more slowly than innate
- more specific and effective
Humoral:
- B lymphocytes respond and release antibodies
- antibodies are the effector molecules
- block infections and eliminate extracellular
microbes
Cell-mediated:
- Helper T cells or Cytotoxic T cells
- eliminate intracellular or phagocytized microbes

Question 2

Define antigens and their relationship to immune recognition

Answer 2

• molecules recognized by the adaptive immune system
• any chemical structure, typically proteins, glycoproteins, and polysaccharides
• recognized by B and T cells

Question 3

Define epitopes and their relationship to immune recognition

Answer 3

• sites within antigens in which antigen receptors bind
• can can conformational (discontinuos) or linear (continuous)
• macromelcular agents can be recognized by different antigen receptors

Question 4

Explain key properties of adaptive immune responses: specificity

Answer 4

ensures immune responses are limited to microbial pathogens

Question 5

Explain key properties of adaptive immune responses: diversity

Answer 5

enables immune system to respond to a large variety of antigens

Question 6

Explain key properties of adaptive immune resposnes: memory

Answer 6

leads to enhanced responses to repeated exposures of the same antigen

Question 7

Explain key properties of adaptive immune responses: clonal expansion

Answer 7

increases number of antigen-specific lymphocytes from small number of naiive lymphocytes

Question 8

Explain key properties of adaptive immune responses: specialization

Answer 8

generate responses optimal for defense against different microbes

Question 9

Explain key properties of adaptive immune responses: contraction and homeostasis

Answer 9

allows immune system to respond to newly encountered antigens

Question 10

Explain key properties of adaptive immune responses: nonreactivity to self

Answer 10

prevents injury to the host during immune response

Question 11

Describe the general functions of antigen-presenting cells

Answer 11

• dendritic cells (initiate T cell response), macrophages (mediated cell immunity), B cells, follicular dendritic cells (humoral immune response)
• capture antigens to display on cell surface for lymphocytes

Question 12

Describe the general functions of T and B lymphocytes

Answer 12

Helper or Cytotoxic T: cell-mediated immunity
-Helper: release cytokines to activate macrophages, cause inflammation, activate B cells
-Cytotoxic: kill the cell
B: humoral immunity
-secrete antibodies to bind to antigens on extracellular microbes

Question 13

Describe the general functions of natural killer cells

Answer 13

kill infected cells

Question 14

Explain the general roles of generative/primary lymphoid organs in the immune system

Answer 14

• sites of lymphocyte cell development

- bone marrow and thymus

Question 15

Explain the general roles of peripheral lymphoid organs/tissues in the immune system

Answer 15

• site of lymphocyte activation by antigen
• spleen (filter for antigens in blood)
• lymph nodes (filter for antigens in lymph)
• mucosal and cutaneous lymphoid tissues (for immune responses that breach the skin)

Question 16

Explain the general roles of lymphatics in the immune system

Answer 16

• system of vessels that collect lymph
• interspersed with lymph nodes
• fats, fluids, and foreign particles make up lymph

Question 17

Describe the basic concept and significance of lymphocyte recirculation and migration into tissues

Answer 17

• lymphocytes recirculate in lymph

- lymphocytes exit lymphoid tissue via lymphatics, move through blood, migrate to sites of infection, fight

Question 18

Describe the phases and key players in an immune response to a microbe including the innate and adaptive response

Answer 18

1) Innate immunity
2) Antigen recognition - antigen-presenting cell + Naive B/T cell (then clonal expansion)
3) lymphocyte activation - differentation antibody-producing cell & effector T-lymphocyte
4) antigen elimination - humoral and cell-mediated immunity
5) contraction/homeostasis - apoptosis
6) memory - surviving memory cells

Question 19

Explain the general concept of immune-mediated damage and their relationship to disease

Answer 19

-hypersensitivity (excessive immune response) or autoimmunity (attack the host)

Question 20

Explain the general concept of immunodeficiency and their relationship to disease

Answer 20

-compromised immune system that leads to increase in the number of infections

Question 21

What is passive immunity?

Answer 21

• a form of adaptive immunity

- recieve antibodies from mother (breastfeeding) or through plasma of someone else who has antibodies

Question 22

What are PAMPs?

Answer 22

• Pathogen-Associated Molecular Patterns
• structures shared by various classes of microbes
• NOT present in noral mammalian cells
• recognized by pattern recognition receptors (PRR)

Question 23

What are DAMPs?

Answer 23

• Danger-Associated Molecular Patterns
• molecules released from damaged or necrotic mammalian cells
• not released by healthy cells
• recognized by certain receptors

Question 24

What is an antibody/immunoglobin?

Answer 24

• membrane-bound or secreted protein
• membrane bound: antigen receptor for B cells
• secreted: effector molecules of humoral immunity

Question 25

What are cytokines?

Answer 25

-proteins made and secreted from a variety of cells that mediate inflammatory responses and communication in the immune system