Exam 4: Immune System

Question 1

primary functions of the immune system

Answer 1

1. protects the body from disease-causing invaders (pathogens and antigens)
2. removes dead or damaged tissues and cells (inflamed cells, old blood cells)
3. recognize and remove “abnormal self” cells (cancer cells)

Question 2

key features of immune system

Answer 2

specificity: enable body to distinguish “self” from “non-self”

memory: immune response is stronger in the second stimulation

Question 3

what happens if the immune system fails?

Answer 3

incorrect response: autoimmune diseases (type 1 diabetes or IBD

overactive response: allergies, allergic hypersensitivity reactions

lack of response: immunodeficiency diseases, AIDS, HIV

Question 4

types of lymphoid tissue

Answer 4

primary: thymus gland and bone marrow

secondary: lymph nodes and spleen

Question 5

primary lymphoid tissue

Answer 5

role: nurture immune cell development

naive immune cells have not encountered the proper antigens

cells involved in the immune response form and mature

Question 6

secondary lymphoid tissue

Answer 6

role: get matured immune cells to interact with pathogens and initiate a response

categories: encapsulated and unencapsulated diffuse lymphoid tissues

Question 7

bone marrow

Answer 7

spongy tissue inside some bones like hip and thigh bones

contains stem cells that can develop into red blood cells and white blood cells (immune cells) that can fight infections

Question 8

thymus gland

Answer 8

on the chest between the lungs

makes T lymphocytes which help fight infection

Question 9

lymph node

Answer 9

small bean shaped structure

filter substances that travel through the lymphatic fluid

contain white blood cells that help the body fight infection and disease

connected to each other by lymph vessels

Question 10

spleen

Answer 10

largest lymphoid organ in the body

immune cells in the spleen monitor blood for foreign invaders

phagocytes in the spleen trap and remove old red blood cells

Question 11

basophils and mast cells

Answer 11

release chemicals that mediate inflammation and allergic responses

Question 12

granulocytes

Answer 12

white blood cells whose cytoplasm contains prominent granules

Question 13

phagocytes

Answer 13

engulf and ingest their targets

Question 14

cytotoxic cells

Answer 14

kill the cells they are attacking

Question 15

antigen-presenting cells

Answer 15

display fragments of foreign proteins on their cell surface

Question 16

neutrophils

Answer 16

50-70% of all white blood cells

1-2 days life span

ingest and kill 5-20 bacteria

make pus: thick fluid caused by infection that includes white blood cells and cellular debris

chemotactic migration to chemical signals such as IL-8, leukotriene that induces production of ROS such as H2O2 and inflammation

Question 17

eosinophils

Answer 17

associated with allergic reactions and parasitic diseases

pink-orange color

1-3% of all leukocytes

life span of 6-12 hours

location: GI tract, lungs, epithelium of urinary and genital tracts, and connective tissue of skin

produce ROS (reactive oxygen species such as superoxide, peroxide), cytokines, and enzymes (elastase in asthma)

attach to large antibody-coated parasites and release substances that kill them

Question 18

basophils and mast cells

Answer 18

located in the systemic circulation (0.5-1% of circulating WBCs)

mast cells are found in the local tissues

dark violet granules

contain chemicals that are involved in immune and allergic responses such as histamine, heparin, and cytokines

Question 19

dendritic cells

Answer 19

characterized by long, thin processes that resemble the dendrites of the neuron

APCs: present antigens to lymphocytes to activate them

Question 20

antigen-presenting cells

Answer 20

recognize and capture antigens

dendritic cells, macrophages, and B cells

Question 21

monocytes

Answer 21

precursor cells of macrophages and dendritic cells

circulating version of macrophages and DC

spend ~8 hours in transit from the bone marrow to tissues where they differentiate into macrophages

Question 22

macrophages

Answer 22

primary scavengers for the tissues

can ingest up to 100 bacteria

remove dead blood cells and dead neutrophils

antigen presenting cells

Question 23

lymphocytes

Answer 23

responsible for acquired immune response

5% of all lymphocytes are in circulation and the rest are located in lymphoid tissues

make up 20-35% of all circulating white blood cells

Question 24

t lymphocytes

Answer 24

cell-mediated imkmunity

Question 25

b lymphocytes

Answer 25

antibody-mediated immunity

Question 26

types of immunity

Answer 26

1. physical and chemical barrier 2. innate immune system (all animals possess) 3. adaptive immune system (all vertebrates possess)

Question 27

innate immune system

Answer 27

non-specific begins within minutes to hours produces general inflammatory response when pathogens penetrate physical barriers

Question 28

adaptive immune system

Answer 28

can adapt to defend against any invader response to a first exposure to a pathogen may take days important when the innate immune system cannot defend against an attack provides the immune system with "memory"

Question 29

components of the innate immune system

Answer 29

1. professional phagocytes: macrophages and neutrophils 2. complement system: proteins that tag stuff for destruction 3. natural killer (NK) cells: mast cells and basophils

Question 30

macrophages

Answer 30

patrol periphery become activated when they find an invader when activated: 1. send signals to recruit other immune system cells (neutrophils) 2. become vicious killers (phagocytosis) 3. present antigen to adaptive immune system

Question 31

what activates macrophages

Answer 31

chemotaxins: bacterial toxin, cell wall components tissue injury debris: fibrin, collagen fragments chemotactic cytokines by leukocytes

Question 32

mechanism of attachment during phagocytosis

Answer 32

patterning recognition receptor to binding binding to antibody hydrophobicity

Question 33

patterning recognition receptor to binding

Answer 33

phagocytic cells' patterning recognition receptor can bind bacteria directly by surveilling the pathogen-associated molecular pattern

Question 34

binding to antibody

Answer 34

phagocytic cells can bind the Fc portion of antibody binding of several antibodies on macrophages activates phagocytosis and microbial killing

Question 35

hydrophobicity

Answer 35

hydrophobic groups tend to attach to the hydrophobic surface of cells may explain the recognition of damaged cells, denatured proteins, etc

Question 36

mechanism of killing and digestion during phagocytosis

Answer 36

lactoferrin oxygen and the oxygen burst nitric oxide (NO)

Question 37

lactoferrin

Answer 37

protein that inhibits bacteria by depriving them of iron which it binds with an extremely high affinity

Question 38

oxygen and the oxygen burst

Answer 38

intracellular killing of many bacteria requires the uptake of oxygen by the phagocytic cell reactive oxygen species are highly toxic to microorganisms NO produced from arginine is another reactive oxygen containing compound that is highly toxic to microorganisms

Question 39

complement proteins

Answer 39

about 30 plasma and cell membrane proteins present in tissues and blood attach to surfaces of bacteria and viruses - 1. target them for destruction by phagocytes or by making pores - 2. form membrane attack complexes recruit other immune cells from blood

Question 40

functions of complement system

Answer 40

opsonization and phagocytosis lysis agglutination neutralization of viruses chemotaxis activation of mast cells and basophils inflammatory effects

Question 41

opsonization and phagocytosis

Answer 41

opsonins are used to tag foreign antigens and strongly activates phagocytosis by both neutrophils and macrophages

Question 42

lysis

Answer 42

combination of multiple complement factors can directly rupture the cell membranes of bacteria or other invading organisms

Question 43

agglutination

Answer 43

the complement products also change the surfaces of the invading organisms, causing them to adhere to one another promoting agglutination (clumping of particles together)

Question 44

neutralization of viruses

Answer 44

complement enzymes and other complement products can attack viruses and thereby render them non-virulent

Question 45

chemotaxis

Answer 45

chemical stimulus initiates the movement of neutrophils and macrophages

Question 46

activation of mast cells and basophils

Answer 46

cells become activated which causes them to release histamine, heparin, and several other substances into the local fluids

Question 47

inflammatory effects

Answer 47

1. increase blood flow further 2. increase the capillary leakage of proteins 3. coagulate the interstitial fluid proteins in the tissue spaces, preventing movement of the invading organism through the tissues

Question 48

natural killer cells

Answer 48

innate response against viral infection innate immune response because they lack antigen-specific cell surface receptors release granzyme (protease) NK cells induce virus-infected cells to commit suicide (apoptosis) secrete antiviral cytokines (interferons) interferons interfere with viral reproduction in the body

Question 49

release of histamine

Answer 49

released by mast cells and basophils initiates inflammatory response induce WBC recruitment from the blood stream

Question 50

histamine action

Answer 50

1. opens pores in capillaries: release of plasma protein causes local edema/swelling 2. dilates blood vessels increasing blood flow: bring about hot, red, swollen area around the wound or infection site

Question 51

adaptive/acquired immune system

Answer 51

two main components fight pathogens outside of cells: b lymphocytes/antibody-mediated immunity fight pathogens inside of cells: t lymphocytes/cell-mediated immunity

Question 52

function of antibodies

Answer 52

1. activates b lymphocytes 2. acts as opsonins 3. causes antigen clumping and inactivation of bacterial toxins 4. activates antibody-dependent cellular activity 5. triggers mast cell degranulation 6. activates complement

Question 53

b cells

Answer 53

lymphocytes that make antibodies b cell receptors on the surface 100 million different types of b cells that each have different surface receptors b cell receptors are so diverse they can recognize every organic molecule

Question 54

when a b cell binds antigen...

Answer 54

b cells are activated and differentiated into plasma cells plasma cells secrete antibodies at the rate of approximately 2000 molecules per second

Question 55

how do T cells identify virus infected cells?

Answer 55

antigen presentation all nucleated cells have major histocompatibility complexes on the surface when virus invades the cell, fragments of viral protein are loaded onto MHC proteins T cells inspect MHC proteins and use this as a signal to identify infected cells

Question 56

MHC class I molecules

Answer 56

all nucleated cells infected cells display viral antigens on MHC I cytotoxic T cells recognize a cell with foreign antigen fragment and kills the cell

Question 57

MHC class II molecules

Answer 57

macrophages, b lymphocytes, and dendritic cells helper T cells recognize a cell with foreign antigen fragment on its MHC II helper T cells secrete cytokines that enhance the immune response

Question 58

lymphocytes clones and memory effects

Answer 58

at birth, each clone of lymphocytes is represented by only a few cells called naive lymphocytes exposure to an antigen triggers clonal expansion and the immune response

Question 59

primary immune response

Answer 59

clone of B and T cells are built up over the course of 1 week when the infection is over, these cells die off and the ones that remain are memory cells B lymphocytes become plasma cells which can secrete antibodies to treat the disease in the future peak antibody concentration occurs about 2 weeks after exposure

Question 60

secondary immune response

Answer 60

memory cells can activate more easily and reproduce effector and memory cells that will turn into plasma and secrete antibodies peak antibody concentration occurs around 3 weeks post exposure, BUT antibody concentration rises immediately after exposure to yield a faster response that is also stronger in just a few days, secondary immune response will yield the peak amount of antibodies that were secreted in the primary immune response aka: can become stronger faster

Question 61

bacteria

Answer 61

cells have membrane and cell wall can survive outside the host can reproduce without a host can be killed or inhibited by antibiotics

Question 62

how do bacteria cause disease?

Answer 62

invade the host reproduce and overgrow deplete nutrients, ions, and oxygen secrete organic wastes produce toxins that disturb the normal functions of cells

Question 63

immune response to bacteria

Answer 63

complement proteins make membrane attack complex that lyses bacteria complement proteins activate mast cells that secrete chemotaxins and histamine (chemotaxins attract circulating leukocytes that will ingest and disable bacteria or secrete antibodies)

Question 64

virus

Answer 64

contains nucleic acid core (DNA or RNA) with protein envelope uses the intracellular machinery to reproduce - virus causes host cell to lyse OR viral particles will bud from the host cell surface) cannot be killed with antibiotics

Question 65

how do viruses cause disease?

Answer 65

virus invades the host cell - binds to membrane receptors - endocytosis brings virus into the cell virus takes over the cell - use viral nucleic acid and host cell resources to make new viral nucleic acid and proteins more virus is released from host cell - virus causes the host cell to lyse OR viral particles bud from the host cell surface

Question 66

immune response to viruses

Answer 66

MHC I presenting - attacked by cytotoxic T and NK cells - granzymes - infected cell is destroyed MHC II presenting - macrophage ingests the virus - secretes cytokines for inflammatory response - macrophage presents antigen fragments - activates helper T cell - activates B lymphocytes - become plasma cells that secrete antibodies

Question 67

human immunodeficiency virus (HIV)

Answer 67

fast mutation of the viral genome - antibodies fail to coat the viral particles for phagocytosis by macrophages - macrophages fail to phagocytose (failed to transferred to lysosome) and virus invade macrophages after viruses infect cells, T lymphocytes are the main defense - failed - helper T cells are infected by the virus - cytotoxic T cells use viral antigen-MHC I to recognize the infected cells and kill them BUT also kill T cells - virus down regulate MHC expression to escape cytotoxic T cells

Question 68

COVID 19

Answer 68

targets angiotensin converting enzyme (ACE2) to get into host cells ACE2 found on apical surface of the epithelium in the lung, arteries, heart, kidney, and gut once coronavirus binds to ACE2, complex internalizes into the cytoplasm via endocytosis in the lung, attacks type II alveolar epithelium since it has a lot of ACE2 on the surface disrupted type II alveolar epithelium results in reduced surfactant production --> lung malfunction damaged type II alveolar epithelium produces multiple cytokines that recruit macrophages in the lung

Question 69

mRNA vaccine

Answer 69

mRNA with instructions for making spike protein put into vaccine mRNA enters the cell virus spike protein is created spike protein is recognized by the immune system and specific antibodies are produced if infected, antibodies bind to the virus and stop it from replicating

Question 70

sensitization

Answer 70

initial exposure to an allergen

Question 71

allergic reaction

Answer 71

secondary exposure to same allergen causes more antibody binding to mast cells for release of histamine

Question 72

anti-histamine

Answer 72

decreases vascular permeability decreases bronchoconstriction

Question 73

corticosteroids

Answer 73

reduce general inflammatory response

Question 74

epinephrine (adrenaline)

Answer 74

constricts blood vessels intramuscular or intravenous injection

Question 75

autoimmune disease

Answer 75

immune system mistakenly attacks your body foreign antigens that are similar to human antigens can be a trigger - body makes antibodies BUT antibodies have enough cross-reactivity with human tissues to do some damage

Question 76

multiple sclerosis

Answer 76

white matter of the brain and spinal cord

Question 77

rheumatoid arthritis

Answer 77

joint lining

Question 78

type 1 diabetes

Answer 78

the pancreas

Question 79

lupus

Answer 79

kidneys and other organs

Question 80

guillan barre syndrome

Answer 80

peripheral nerves

Question 81

rheumatoid arthritis treatment

Answer 81

stimulation of the vagus nerve prevents cytokine production which reduces activation of cells which traffic to the joint

Question 82

immune checkpoint inhibitor

Answer 82

PD-L1 on tumor cells PD-1 on T cells binding of PD-L1 to PD-1 keeps T cells from killing tumor cells blocking this binding allows the T cells to kill tumor cells - can be accomplished by inhibiting either PD-1 OR PD-L1 in the case where it is inhibited, the T cell receptor and antigen bind, but PD-L1 and PD-1 do not

Question 83

chimeric antigen receptor T (CAR-T) cell therapy

Answer 83

white blood cells including T cells are separated out and the rest of the blood is returned to patient T cells are engineered to find and kill cancer cells - inactive virus inserts genes into T cells - genes cause T cells to make CARs (special receptors) on their surfaces - modified T cells are multiplied until there are millions of these attacker cells CART cells put back into patient's blood to make space and continue to multiply CART cells identify the cancer cells with target antigens and kill them; remain in the body to prevent reemergence of cancer

Question 84

CRISPR-editing for allogenic CAR-T therapy

Answer 84

knocks out MHC 1 and TCR for prevention of immuno-response