MMI133_Lecture11

Question 1

Hypersensitivity

Answer 1

immune system goes haywire/doesn;t work properly

Question 2

4 types of hypersensitivity

Answer 2

Type 1: Allergy
- localized or general anaphylaxix/shock
IgE mediated
Type 2: Cytotoxic
- blood attacks
Type 3: Immune complex mediated
Type 4: Delayed cell-mediated

Question 3

all hypersensitivity reactions that cause tissue damage require

Answer 3

previous exposure to antigen/allergen

Question 4

Type 1 Reactions

Answer 4

localized - hives/ urticaria
hay fever, allergic rhinitis

systemic or general
shock, need epi-pen, peanut allergies

Question 5

Type 1 reactions phases

Answer 5

1. sensitization - result of classical antigen presntation with T helper cell involvement + B cell activation
2. activation - cross linking of at least 2 IgE molecules bound to Fc receptors on mast cell - triggers mast cell/basophil degranulation
3. effector
   - phase 1 primary mediators released - histamine, eosinophil, chemotactic factor, neutrophilchemotactic factor, proteases
   - phase 2 secondary mediators released leukotrienes + prostaglandins

Question 6

the only type of hypersensitivity with no antibodies involved is

Answer 6

type 4 - delayed cell-mediated

Question 7

type 1 systemic reactions

Answer 7

immediate reaction (minutes)
life threatening impaired breathing to swelling of airways
uterine cramps, involuntary urination/defecation = due to smooth muscle contraction
edema from fluid leaking into tissue spaces
blood pressure drops leading to life-threatening anaphylactic shock bec BV’s widen and blood leaks out

Question 8

mediators from primarily mast cells + basophils

Answer 8

histamine + other lipid moelcs + cytokines

collectively act to:
- inc permeability + dilate BV’s - lead to edema + erythema/redness
- inc mucus secretion + contract smooth muscle

Question 9

treatment of anaphylaxis

Answer 9

antihistamines to block action of histamine

epinephrine (epi-pen) - to contrict BV’s + raise BP
dilates air passages in lunges, effects smooth muscles

Question 10

Type 2 cytotoxic reactiosn

Answer 10

due to diff blood types having diff antigens on their surfaces, getting anoth kind of blood that has diff antigens and teh immune system sees the blood as non-self and attacks + kills RBC - leads to hemolysis of RBC’s

Question 11

blood type A has

Answer 11

anti B antigens

compatable blood types are A + O

Question 12

blood type B has

Answer 12

anti A antigens

compatable blood types are B + O

Question 13

AB blood type has

Answer 13

no antibodies in plasma

compatable blood types: A, B, AB, O

universal recipient - can get anything

Question 14

O blood type has

Answer 14

anti A + anti B antibodies and no antigens

compatable blood types are O

it is the universal donor, but can only accept O blood types

Question 15

key components of type 2

Answer 15

complement system
cell-bound antigens
antibodies IgG + IgM

Question 16

HDN = hemolytic disease of newborn = blue baby

Answer 16

mother Rh- baby Rh+
with first baby, mother is exposed to Rh+ blood which has D+ antigen, so mother becomes sensitized to that antigen + immune system produces D+ antibodies

next baby, more baby blood leaks into mum, mum’s antibodies are small enough to get into placenta + attack baby blood + cause hemolysis of baby’s blood, results in baby with less blood + annemia + at risk of respiratory issues + bad for baby maybe death
ne

Question 17

baby blue

Answer 17

not enough o2 due to hemolysis

Question 18

prevention of Rh sensitization as treatment to prevent hymolytic disease of newborn

Answer 18

rhogam administration to Rh- mothers before + after delivery
to rapidly eliminate fetal Rh+ RBC’s from maternal circulation + hide them from mothers immune system
prevents maternal B cell activation against Rh antigens

Question 19

Type 3 Immune complex mediated

Answer 19

immune complex binds to endothelium then activates complement which generates chemoattractants for neutrophils which arrive then release their granules + enzymes to damage tissue

poststreptococcal glomerulonephritis or SLE
immune complex deposition is typically in skin, joints, + kidney (glomerular basement membrane)

immune complex AB+AG circulate in blood circulation which is called soluble

Question 20

Type 4 delayed cell mediated reaction

Answer 20

no antibodies involved
takes several days to develop
T cells involved
poison oak + ivy
Tb tests
Th1 cells + macrophages
requires previous exposure + presence of T memory cells

principal effector cell is activated macrophages which release lytic enzymes that cause local tissue destruction

mechanisms of tissue destruction: cytotoxic T lymphocytes induced by Th1 cells to assist in tissue damage

Question 21

allergic response of type 4 delayed cell mediated

Answer 21

contact dermatitis
triggered by poison oak + ivy
oils from plant act as haptens binding to skin proteins
complexes are presented by skin dendritic cells to Th1 cells initiating immune response

treatment with corticosteroids for contact dermatitis immunosuppressive drugs including cortisone for transplant rejection

Question 22

other type 4 reactions

Answer 22

tuberculin test: assesses immune response to Tb
transplant rejection: immune reaction against foreign tissues

Question 23

how does Tuberculin skin test work?

Answer 23

determines prev exposure to TB by Iding memory cells reactive to TB antigens
widesly used in NA bec not many people immunized against TB

cell mediated reaction type 4
involves infiltration of lymphocytes + macrophages due to mobilization by pre-existing memory cells

Question 24

limitations of tuberculin tests

Answer 24

inapplicaability to certain pops
anergic individs are unresponsive to immune stimuli like AIDS
immunosuppressed patients won’t react redictably to test which can make it unreliable

lack of specificity
those vacc with BCG vax give false positives

Question 25

quantiFERON-TB Gold test

Answer 25

tests for memory cells + activated T lymphocytes thru interferon production helps confirm + rule out latent TB + active tb + prev BCG effects, pateints don't need to go back to have it read requires blood sample to be processed within 12 hrs deals with BCG effects

Question 26

caparison of hypersensitivty reactions

Answer 26

type 1: IgE, exogenous antigen, 15-30 min response, wheal + flare, mast cells, allergic asthma, hay fever type 2: IgG, IgM, cell bound antigen, min-hrs response, lysis + necrosis, no cells, arythroblastosis foetalis HDN type 3: IgG, IgM, soluble antigen, 3-8 hrs response, erythema, edema, necrosis, no cells, SLE, farmer's lung type 4: no antibodies, tissues + organs antigens, 48-72 hrs, erythema, induration, T-cells + macrophages, Tb test, poison ivy, granuloma

Question 27

jenner observed that milkmaids who contracted cowpox were immune to more severe

Answer 27

smallpox disease

Question 28

types of vaccines

Answer 28

attenuated whole-agent inactivated whole-agent/subunit toxoids conjugated nucleic acid (DNA or RNA)

Question 29

Attenuated whole agent vaccines

Answer 29

live attenuated vaccines with weakned microbes that mimic real infections 95% effective often providing life-long immunity stimulates both humoral antibody + cell-mediated immunity + creates memory cells Sabin (polio) MMRV (measles, mumps, rubella, varicella) risk of mutation back to virulent form can't use for immunocompromised or pregnant women

Question 30

inactivated + subunit vaccines

Answer 30

use killed whole microbes or parts of organisms like glycoproteins rabies, salk (polio), influenza, gardasil, hepatitis B safe for immunocompromised + preg women no risk of reverting back to wild-type limited cell-mediated immunity no CD8+ response, shorter lasting immunity stimulates B cell memory, needs boosters

Question 31

toxoids

Answer 31

toxin isolated + chemically treated to preserve autigenicity but make toxin non-functional toxoid used as vax to produce antibodies to toxin not microbe - only humoral immunity requires boosters for full immunity diphtheria tetanus

Question 32

conjugated vaccines

Answer 32

for organisms with polysaccharide capsules, poor antigens doesn't work for children <2yrs polysaccharides from capsules are combined with a protein which is highly immunogenic which fools immune system into reacting to protein + get immunity to carbohydrates Haemophilus influenzae type b Neisseria meningitidis Streptococcus pneumoniae

Question 33

Nucleic acid vaccines

Answer 33

DNA vaccines: gene from organisms into human host cell to get transcribed covid Astra-Zeneca + johnson/johnson vax RNA: changed mRNA + produce protein that stimulates our usual adaptive immune system. leaves cells within 3 wks works 95% effectivity, needs boosters Pfizer + Moderna

Question 34

what is vax controversy all about

Answer 34

MMR causes autism too many vax for infant immune systems to handle toxic chemicals used to preserve vax use of fetal cells for growing (TRUE) virus used in vax too many vax for baby to tolerate natural infection produces better immunity + makes immune system stronger

Question 35

naturally acquired active immunity

Answer 35

indiv exposed to antigens in course of daily life where clinical or subclinical infectiosn can confer immunity child gets chickenpox

Question 36

naturally acquired passive immunity

Answer 36

natural transfer of antibodies maternal transfer of IgG antibodies over placenta IgA antibodies in mothers's breast milk

Question 37

artificially acquired active immunity

Answer 37

result of vax, where specialized prepared antigens (vaccines) are introduced into body susbstances are altered so that they can no longer cause disease, but can stimulate an immune response immunity after mump vaccine

Question 38

artificially acquired passive immunity

Answer 38

involves introduction of antibodies form an animal or person who is already immune tot eh disease varicella immunoglobulin given after exposure of unimmunized person to varicell (antibodies pooled from blood donor sera)

Question 39

the tuberculin test is

Answer 39

not a vax, but a diagnostic test using the type 4 hypersensitivity reaction to gauge patient exposure