Immunology & Immunizations

Question 1

Describe the lines of defense of the immune system

Answer 1

First: (innate) external skin/mucosal membranes

Second: (innate) antimicrobial proteins, phagocytes, other cells that inhibit spread of invaders & trigger inflammation

Third: adaptive immune system

Question 2

Describe how the surface barriers protect us against microorganisms

Answer 2

• protective chemicals that inhibit/destroy
• mucus-coated cilia in the respiratory tract sweep microorganisms from lower respiratory passages
• organ surfaces participate

Question 3

Describe the internal defenses of the immune system

Answer 3

cells and chemicals
- phagocytes
- NK cells
- inflammatory response (macrophages, mast cells, WBCs, chemicals)
- antimicrobial proteins (interferons)
- fever

Question 4

Describe phagocytes

Answer 4

type of cell that engulfs and absorbs bacteria, small cells, particles

Question 5

Describe macrophages

Answer 5

• develop from monocytes
• chief phagocytic cells of the immune system
• free macrophages wander through tissue space
• fixed macrophages are permanent residents of some organs

Question 6

Describe neutrophils

Answer 6

become phagocytic upon encountering infectious material in tissues

Question 7

Describe Natural Killer cells

Answer 7

• large granular lymphocytes
• 2 types of receptors (inhibitory recognize self, activating recognize stressed/infected cells)

Question 8

what are the cardinal signs of acute inflammation

Answer 8

redness, heat, swelling, pain (sometimes impairment of function)

Question 9

What are the inflammatory mediators

Answer 9

• histamine
• blood proteins
• kinins
• prostaglandins
• leukotrienes
• complement cells

(released by injured tissue, phagocytes, lymphocytes, basophils, mast cells)

Question 10

Describe the vascular permeability step of the inflammatory process

Answer 10

inflammatory chemicals cause vasodilation resulting in hyperemia & increased permeability & edema of local capillaries that produces exudates (proteins, clotting factors, antibodies)

Question 11

Describe how edema works in the inflammatory response

Answer 11

• results from surge of exudates
• moves foreign materials into lymphatic vessels
• delivers clotting proteins to form a scaffold for repair and isolate the area

Question 12

Describe the main points of th einflammatory response

Answer 12

• triggered when body tissues are injured/infected
• prevents spread of damaging/infectious agents
• disposes of cell debris & pathogens

Question 13

What are the 5 leukocytes

Answer 13

Granulocytes (PMNs)
- eosinophils
- neutrophils
- basophils

• lymphocytes
• monocytes

Question 14

What are the 4 steps of phagocyte mobilization

Answer 14

• leukocytosis: release of neutrophils
• margination: neutrophils cling to capillary walls
• diapedesis: neutrophils pass through
• chemotaxis: inflammatory chemicals promote positive chemotaxis of neutrophils

Question 15

What do complement proteins do

Answer 15

major mechanism for destroying foreign substances (viral infection)
- consist of 30+ blood proteins that circulate in an inactive form

Question 16

describe an interferon

Answer 16

Function
- antiviral
- reduce inflammation
- activate macrophages & mobilize NK cells

Question 17

Describe a fever

Answer 17

• systemic response to invading microorganisms
• leukocytes & macrophages exposed to foreign substances secrete pyrogens
• pyrogens increase the body’s thermostat
• high fevers can denature enzymes
• moderate fevers can increase metabolic rate/repair & sequester iron & zinc in the liver

Question 18

Describe adaptive immunity

Answer 18

• specific, systemic, memory
• Humoral immunity: antibody mediated (B cells)
• cellular immunity: cell mediated (T cells)

Question 19

Define an antigen

Answer 19

• toxin or foreign substance that induces an immune response & production of antibodies
• most are large, complex molecules not normally found in the body

Question 20

Describe B and T lymphocytes

Answer 20

cells of the adaptive immune system

• B (humoral): responsible for creation of antibodies once an antigen provokes a humoral response, mature in red bone marrow
• T (cell-mediated): proliferate & differentiate into effector cells of immunity & helper cells for antibody response by secreting cytokines, mature in thymus, mature = immunocompetence & self-tolerance

recognize and bind to antigens, communicate with each other to mount a specific immune response to destroy non-self substances

Question 21

Describe a primary immune response

Answer 21

• occurs on first exposure to an antigen
• lag period of 3-6 days
• peak levels of plasma Ab reached in 10 days
• Ab levels slowly decline

Question 22

Describe a secondary immune response

Answer 22

• occurs on re-exposure to an Ag
• sensitized memory cells respond within hours
• Ab levels peak in 2-3 days at much higher levels than primary response
• Abs bind with greater affinity
• Ab level can remain high for weeks/months

Question 23

Describe active humoral immunity

Answer 23

When B cells encounter Ags & produce specific Abs against them

Two types
- Naturally acquired: response to bacterial/viral infection
- Artificially acquired: response to a vaccine of dead/attenuated pathogens

Question 24

Describe vaccines roles in active humoral immunity

Answer 24

• spare us the sxs of a primary response
• provide Ag determinants that are immunogenic and reactive
• target only one type of helper T cell so they don’t fully establish cellular immunological memory

Question 25

Describe passive humoral immunity

Answer 25

**B cells not challenged by Abs & immunological memory not occurring* Two types - naturally acquired: Abs delivered to fetus via placenta or infant through milk - artificially acquired: injection of serum such as gamma globulin which provides immediate protection but ends when Abs naturally degrade in the body

Question 26

Flip this card for a nice lil reminder on active vs passive humoral immunity

Answer 26

Question 27

Describe antibodies

Answer 27

- immunoglobulins (gamma globulin portion of blood) - proteins secreted by plasma cells - capable of binding specifically with Ag detected by B cells

Question 28

Describe the cell-mediated immune response

Answer 28

- T cells provide defense against **intracellular** Ags - Types of T cells: Helper T (TH), Cytotoxic T (TC) - Others (Regulatory T cells - TREG, memory T cells)

Question 29

Describe the difference between humoral and cell-mediated immune responses

Answer 29

HUMORAL - B cells produce Abs as a simple form of ammunition - targets: bacterial, molecules in extracellular fluid CELL-MEDIATED - T cells recognize & respond to processed fragments of Ags displaced on surface of body cells - targets: infected body cells, abnormal/cancerous cells, cells of infused/transplanted foreign tissue

Question 30

Describe the role of helper T cells

Answer 30

- central role in adaptive immune response - help activate and induce T & B cell proliferation - activate macrophages & recruitment o fother immune cells **without TH there is no immune response**

Question 31

Describe the role of cytotoxic T cells

Answer 31

directly attack & kill other cells activated Tc cells circulate in blood & lymph in search of body cells displaying the Ag they recognize Targets: - virus-infected cells - cells with intracellular bacteria/parasites - cancer cells - foreign cells

Question 32

What are the 2 types of immunization processes

Answer 32

active vs passive

Question 33

Describe the active immunization process

Answer 33

- used to simulate the body's natural defense mechanisms - contains non-infectious fragments of bacteria/virus OR a toxin produced by that organism that has been modified to a toxoid **immune system responds by producing Abs and other protective substances**

Question 34

Describe the immune response to an active immunization process

Answer 34

**produces a primary immune response through...** - B cell proliferation - Ab response - T-cell sensitization Subsequent exposure results in a secondary response (increased proliferation of B cells & formation of Abs, protects person from developing disease) *may require boosters to sustain protection*

Question 35

Describe live-attenuated active vaccines

Answer 35

- live microbes that are weakened - elicit strong cellular & Ab response often conferring lifelong immunity with 1-2 doses - **contraindicated in those with compromised immune systems** Ex. polio, measles, yellow fever, flumist, zoster

Question 36

List the types of active vaccines

Answer 36

- live-attenuated - inactivated - subunit/recombinant - conjugate - toxoid - mRNA - recombinant vector

Question 37

Describe inactivated active vaccines

Answer 37

- killing the disease-causing microbe with chemicals, heat, radiation - more stable/safer than live vaccines (dead microbe can't mutate back to disease-causing state) - weaker than live vaccines therefore require more in a series or boosters Ex. IPV, Hep A, rabies

Question 38

Describe Subunit/Recombinant active vaccines

Answer 38

- contain only the Ag parts of the pathogen - difficult & expensive to create Ex. Flu shot, pertussis, HPV, Hep B

Question 39

Describe conjugate active vaccines

Answer 39

Made using pieces from the coats of bacteria plus a carrier protein Ex. pneumococcal

Question 40

Describe toxoid vaccines

Answer 40

- protein-based toxin rendered harmless (toxoid) & used as the Ag in the vaccine to elicit immunity - used for bacteria specifically - may require several doses Ex. diphtheria, tetanus

Question 41

Describe mRNA active vaccines

Answer 41

work by teaching our cells to make a harmless piece of a spike protein which is found on the surface of viruses Ex. COVID

Question 42

Describe recombinant vector active vaccines

Answer 42

use an attenuated virus or bacterium to introduce microbial DNA to cells of the body (still in development)

Question 43

Describe the passive immunization process

Answer 43

Abs against a specific infectious organism given directly rather than the body creating them Sources of Abs - animal serum from immune source - pooled human immune globulin - hyperimmune globulin from people known to have Abs to a specific disease - Ab-producing cells grown in a lab

Question 44

Describe the uses for passive immunization

Answer 44

- inadequate immune responses - infection prior to vaccination - to prevent disease when people are likely to get exposed prior to completing a vaccine series - occasionally used for healthcare workers, pregnant women, international travelers (passive immunization lasts only for a few days/weeks until the body eliminates the injected Abs) Ex. Hep A&B, tetanus, varicella

Question 45

Describe the absolute contraindications to vaccines

Answer 45

- serious allergic reaction to a vaccine or one of its components - **live vaccines** should not be used in those with: weakened immune system/immunosuppressed, pregnancy, some neuro disorders like guillain barre - individual per vaccine

Question 46

Describe some of the relative contraindications to vaccines

Answer 46

- recurrent/mild illness - current/recent abx use - previous mild/moderate local tenderness, redness, swelling, fever after any vaccine - previous hx of allergy to specific vaccine contents - fam hx of adverse reactions to immunizations

Question 47

What are the things reported in adverse event reporting

Answer 47

to the US DHHS - anaphylaxis/anaphylactic shock within 7 days of a vaccine - encephalopathy, encephalitis, seizures - any sequelae - serious/unusual events - side effects listed as contraindications to future vaccination on the package insert

Question 48

Describe herd immunity

Answer 48

Question 49

What diseases does strep pneumoniae cause

Answer 49

- pneumonia - otitis media - meningitis - bacteremia in peds, elderly, immunocompromised **leading infectious cause of pneumonia related death in kids worldwide** - rise in resistant pneumococcal strains = urgent need for vaccination

Question 50

What are the immunologic considerations of haemophilus influenzae B

Answer 50

- gram neg anaerobe - opportunistic pathogen (lives in host without causing disease until the right opportunity - decreased vaccine rates have led to an increase in pneumonia, meningitis, and epiglottitis

Question 51

What are the immunologic considerations for pertussis

Answer 51

aka whooping cough - highly contagious respiratory disease - caused by **bordatella pertussis** - uncontrollable, violent barking cough - molecular changes to b. pertussis as well as new vaccine mechanism contributing to resurgence/less protective time - given in Tdap/Dtap vaccine (diphtheria, tetanus, & pertussis)

Question 52

What are the immunologic considerations for Tetanus

Answer 52

- **clostridium tetani** - found in soil, dust, manure, enter through breaks in skin - uncommon in the US - sxs: jaw cramping, sudden involuntary muscle spasm, GI issues, trouble swallowing, seizures, severe HA, fever, sweating, unstable BP and HR

Question 53

What are the immunologic considerations for diphtheria

Answer 53

- caused by **cornybacterium diphtheriae** - person to person spread (respiratory droplets) - thick covering in back of throat leading to difficulty breathing, heart failure, paralysis, death

Question 54

What are the immunologic considerations for meningiococcemia

Answer 54

- **neisseria meningitides** - responsible for bacterial meningitis & sepsis - spread person to person through droplets - vaccination rates reduced disease and epidemics worldwide

Question 55

Describe the immunologic considerations for diarrhea

Answer 55

- multiple etiologies: rotavirus, shigella, enterotoxogenics, e coli, campylobacter, etc - spread through water, food, utensils, hands, flies - death d/t dehydration, electrolyte imbalance

Question 56

Describe the immunologic considerations for rotavirus

Answer 56

- most common cause of severe diarrheal disease in young children - 2 oral, live, attenuated vaccines available internationally (safe & effective, must be given before 8 months old)

Question 57

What are the immunologic considerations for measles

Answer 57

- viral - isolated & extracted measles strain from a sick person's blood in the 1950s to create the first vaccine in the 1960s: Edmonston-B - once dose of measles vaccine is 93% effective in preventing if exposed, 2 doses are 97% effective

Question 58

What are the considerations for immunizations in pregnancy

Answer 58

- protect both mother and baby - can provide passive protection against infections acquired independently after birth - ideally immunized before conception but can be given during pregnancy especially if: high risk exposure, tarotogenic infection, immunizating agent unlikely to cause harm, effectiveness