Introduction

Question 1

What is vaccination?

Answer 1

• Inoculation of healthy individuals with weakened or attenuated strains of disease causing agents to prevent disease

Question 2

What is adaptive immunity?

Answer 2

• The production of antibodies in response pathogens as a result of adaptation to infections
• Requires response time

Question 3

What is innate immunity?

Answer 3

• Nonspecific defense against infections
• Rapid response

ex. Macrophage (wbc) engulfs and digests microorganism

Question 4

What is an antigen?

Answer 4

• A substance that stimulates antibody generation and is recognized by adaptive immunity

ex. proteins, glycoproteins, polysacs of pathogens, metals, organic chemicals, and drugs

Question 5

What is the origin of most leukocytes? What is the exception?

Answer 5

• Most come from bone marrow where many develop and mature
• Certain tissue resident macrophages and lymphocytes (microglia of CNS) originate from yolk sac or fetal liver during embryo development

Question 6

What is the lymphatic system?

Answer 6

• How immune cells travel through peripheral tissue
• Used to drain extracellular fluid and immune cells from tissue and transported as lymph
• lymph drains into the blood stream

Question 7

What two progenitors can be produced from a multipotent hematopoietic stem cell?

Answer 7

• Common lymphoid progenitor
  
  • B cells, T cells, NK cells
  • Adaptive immunity, develops in lymphoidal organs
• Common myeloid progenitor
  
  • All other leukocytes, dendrites, and platelets
  • Innate immunity, develop in bone marrow

Question 8

What are the four disease-causing microorganisms?

Answer 8

• Viruses
• Bacteria and archaea
• Fungi
• Parasites

Question 9

What is a microbiome?

Answer 9

• Colonies of microbial communities that are found on skin, mucosa, gastrointestinal tract and have a symbyotic relationship with the host
• Parasites can often get through mucosa and harm cells

Question 10

What is the order of the body’s defenses against pathogens?

Answer 10

• Anatomical barriers: Skin, mucosa, intestine, respiratory epithelium
• Compliment/antimicrobial proteins: Chemical and enzymatic response near epithelial tissue
• Innate immune cells: Macrophages, granulocytes, NK cells
• Adaptive immunity: B cells and T cells

Question 11

Outline the steps involved in the immune system being activated

Answer 11

• Inflammatory inducers indicate the presence of a pathogen or tissue damage
  
  • Bact. lipopolysac, ATP, Urate crystals
• Sensor cells detect signal via receptors and defend or propagate immune response
  
  • Macrophages, Neutrophils, dendritic cells
• Mediators act on target tissue
  
  • Cytokines, cytotoxicity
• Target tissue produces antimicrobial proteins to kill infected cells

Question 12

Why does adaptive immunity take longer to respond compared to innate immunity?

Answer 12

• Adaptive immunity takes longer because it involves making B cells and T cells with a specific antigen receptor to target the pathogen. Additionally memory cells ensure prolonged protection if the same pathogen invades

Question 13

What is hematopoiesis?

Answer 13

• The development of blood cells, Both red and white, from hematopoietic stem cells
• In bone marrow
  
  • T cells then mature in thymus
  • Mast cells then mature in peripheral tissue
  • Macrophages then mature in tissue

Question 14

What is a macrophage? What are its functions?

Answer 14

• Leukocyte
• Found in tissue
• Circulates (immature) as monocyte
• Involved in Adaptive and innate

Functions:
- Phagocytosis (ingestion)
- Induce inflammation by releasing mediators o recruit immune cells
- Antigen presentation to activate T cells
- Scavenge, clear old/dead cells and debris

Question 15

What is a neutrophil? What is its function?

Answer 15

• Leukocyte
• Also called PMNs
• Most common WBC
• First responder to infections + injuries
• Major player in innate

Functions:
- Phagocytosis (main), and granules are released to digest bacteria
- Cytokine signaling (can signal to other immune cells)

Question 16

What is an Eosinophil? What is its function?

Answer 16

• Leukocyte
• Less abundant than neutrophils
• Granules contain enzymes and toxic proteins

Functions:
- Defend against parasitic infections
- When pathogen is too large to be engulfed it is instead broken down by granules

Question 17

What are Basophils and Mast cells? What is their function?

Answer 17

Both:
- Leukocyte
- Less abundant than neutrophils

Functions:
- Allergic response
- Defend against parasites via granule secretion

Basophils:
- Circulate in blood

Mast cells:
- Found in peripheral tissue
- Skin, intestines, airway mucosa and they’re early sensors of infection or injury

Question 18

What are Natural Killer Cells? What is their function?

Answer 18

• Leukocytes
• Share many functions with T cells
• Cytotoxic molecules (release lytic granules)

Functions:
- Recognize and destroy tumor and infected cells
- Determined by activating and inhibiting ligands for NK’s innate receptors
- Tumor cells: ligand expression decreases which NK cells recognize as non-self

Question 19

What are innate lymphoid cells? What is their function?

Answer 19

• Leukocyte
• In peripheral tissue

Functions:
- Secrete cytokines that regulate immune cells
- Mirror T-cell functions

Question 20

What are dendritic cells? What is their function?

Answer 20

• Leukocyte
• In tissue
• Bridge b/t innate and adaptive immunity

Functions:
- Activate T-cells
- Phagocytosis (innate immune receptors)
- Control response of innate immune cells

Question 21

What are T-cells? What is their function?

Answer 21

• Leukocyte
• Mature in Thymus
• Naive T-cell (immature) has not been exposed to antigen

Functions:
- Effector cells
- Helper T-cells (CD4+)
- Activate immune cells
- Express CD4 co-receptor
- Cytotoxic T-cells (CD8+)
- Release cytotoxins to target cells to cause apoptosis and membrane proliferation
- Regulatory T-cells
- Control immune reaction + prevent autoimmunity
- Inhibit T-cells
- Memory cells
- Have memory of receptors which can be used upon reinfection

Question 22

What is a B-cell? What is its function?

Answer 22

• Leukocyte
• Matures in bone marrow
• Humoral immunity
  
  • Circulation via blood, mucus, tears etc.
• Native B-cells (immature) have not been exposed to antigen

Functions:
- Effector cells
- Plasma cells (produce antibodies)
- Memory B-cells
- Function as antigen presenter

Question 23

What is an antigen? What is Immunogenicity? What is Antigenicity?

Answer 23

• Any molecule that can specifically to an antibody or generate peptide fragments that are recognized by a T-cell receptor
  
  • Proteins, glycoproteins, polysac, lipids, drugs, metals, chemicals
  • Epitope is a region by which an antigen can be recognized by antigen receptors or antibodies
• The ability to induce humoral/cell-mediated immune response
• The ability of an antigen to bind/interact w/ B or T cell receptors

Question 24

What are the 6 types of antibody function?

Answer 24

• Agglutination - aggregation
• Neutralization
• Opsonization - recognition and phagocytosis of microbes
• Cytotoxicity
• Degranulation
• Compliment activation

Question 25

What are cytokines?

Answer 25

- Proteins made by a cell to illicit response - Cell signaling - Often called interleukins (IL-n)

Question 26

Identify the different leukocytes.

Question 27

What are the different types of microbes?

Answer 27

- Bacteria - single celled, prokaryotes - Viruses - genetic material surrounded by protein coat - Fungi - single to multicellular, surrounded by protein coat - Parasites - Protozoans (single cell euk) or helminths (worms)

Question 28

What are three mechanisms pathogens use to damage tissue?

Answer 28

- Exotoxin production - Proteins produced inside the pathogenic bacteria and secreted into surrounding - Endotoxin - Constitutive elements of bacteria membrane that are released when bacteria die - Direct cytopathic effect - Pathogen harms its host cell

Question 29

What are the two types of bacteria?

Answer 29

- Gram positive (GP) - One membrane and thick layer of peptidoglycan - Gram negative (GN) - Two membranes + thin peptidoglycan layer - Lipopolysaccharides (LPS) outer membrane

Question 30

What can bacteria do to spread?

Answer 30

- Release toxin from outside of cells - Invade the tissue - Mix of both

Question 31

Where can extracellular infection come from? Where can intracellular infection come from?

Answer 31

- Respiratory system, Renal system, CNS - Immune cells, Epithelial cells, Mesenchymal cells

Question 32

What are the two types of viruses?

Answer 32

Naked: - Protein coat (Capsid) - Spike (membrane protein involved in entry to host) Envelope: - Additional membrane envelope Both: - RNA and DNA contents can be single or double stranded

Question 33

What are the general steps of viral infection?

Question 34

What are fungi?

Answer 34

- Eukaryotes - Unicellular (yeast, budding) or multicellular (molds, asexual spores) - Most fungi are opportunistic - Dimorphic fungi are true pathogens - Can invade extra or intracellularly

Question 35

What are parasites?

Answer 35

- Protozoans - Grouped by locomotion - Intra or extra - Helminths - Worms66 - Round, flat, segmented