Module 2 - Epidemiology Flashcards
Lymphocytes
T Cells
B Cells
Types of Immunity (5)
Innate
Adaptive
Passive
Active
Acquired
Types of antibodies
M = first to be produced, not as effective. agglutination.
A = found in seromucosal secretions (breast milk), respiratory tract
G = most effective. agglutination, neutralization, complement enhancement. cross placenta
E = involved in allergic reactions –> increase histamine rls
D
IgG
most abundant in human blood
can cross placenta
most versatile
IgM
first one to be produced
diagnostic marker
IgA
can be passed into breast milk
found in mucous tracts –> respiratory, GI, GU
helps trap pathogens in mucus
IgE
least abundant in body
anti-parasitic defenses
binds to basophils/mast cells (immune-mediated allergy?)
IgD
located on surface of B-cells
not secreted
Types of T-cells
helper
regulatory
cytotoxic
Types of T-helper cells
Specific to a protein antigen
TH1
TH2
Which cells do TH1 cells activate?
macrophages
cytotoxic T-cells
NK cells
Which cells do TH2 cells activate?
B-cells do for protein antigens.
promote class-switching –> switch antibody production
*Th dependent immunity
Which protein binds to helper/regulatory T-cells
CD4
Which protein binds to cytotoxic T-cells
CD8
MHC I
found on all nucleated body cells (except RBCs)
present ‘self-antigen’s & pathogens.
can be found on APCs d/t cross presentation
MHC II
found on antigen presenting cells
Primary immune response
when body is first exposed to a pathogen
takes longer, less antibody production (mostly IgM)
body develops antibodies ~10 days
Secondary immune response
memory cells result in faster and stronger immune response. higher number of IgG antibodies
Types of vaccines (6)
live attenuated
inactivated
subunit
conjugate (protein + polysaccharide)
toxoid
DNA/RNA
Independent antigens
carbohydrates
lipids
stimulate B-cells w/o TH2 cells but only result in IgM antibodies. no memory cells.
not immunogenic <2 years old
Dependent antigens
proteins linked to polysaccharide
stimulate T-helper cells whic results in a more robust immune response & production of IgG antibodies
Types of immune defenses
physical
chemical
mechanical
cellular
molecular
Types of molecular defenses
cytokines
chemokines
complement proteins
Vaccine efficacy
how effective vaccine works in clinical setting
Vaccine effectiveness
how effective vaccine works in real world setting
Levels of injury prevention
primary = prepathogenesis
secondary = early pathogenesis
tertiary = middle/late pathogenesis
Phagocytes
neutrophils
macrophages
monocytes
dendritic cells
What 2 cells does a monocyte differentiate into
macrophage
dendritic cell
What are APC’s
dendritic cells
macrophages
B-cells
VDJ recombination
process in different gene segments are spliced together resulting in different antigen receptors on lymphocytes
Class switching
process in which plasma cells switch antibody production (i.e. IgM –> IgG)
Types of immunoprophylaxis
vaccines
immunoglobulins
Types of vaccines
live attenuated
inactive
subunit
recombinant
DNA/RNA
Extracellular immunity
antibodies (humoral)
Intracellular immunity
cytotoxic T-cells
Antigen
molecule recognized by active lymphocytes/antibodies based on 3D structures (epitopes)
Immunogen
specific antigens that can stimulate the adaptive immune system
Immunogen characteristics
proteins
carbohydrates (polysaccharides)
large with repeating epitopes
foreign molecules
Adjuvants
substances added to vaccines to enhance immune response
Common adjuvants
aluminum salt
emulsions (squalene)
microbial derivatives
cells/cytokines
thimerosal (preservative)
formaldehyde (kill bacteria)
Types of surveillance
Passive
Active
Rumor
Syndromic
Passive surveillance
routine reporting
reportable diseases
government registries
hospital data
Active surveillance
outbreak investigation
serosurveillance
health survey
IMPACT
Rumor surveillance
news
social media
phone
Syndromic surveillance
monitor medicine purchase, work absenteeism –> symptoms suggesting disease outbreak
early detection
public information
IMPACT
Canadian Immunization Monitoring Program Active
AEFI
adverse events following immunization but may not be CAUSED by immunization
Anaphylaxis skin
hives
swelling
itching
redness
warm
*d/t histamine rls
Anaphylaxis respiratory
throat swelling –> wheezing/stridor
SOB
coughing
chest pain/tightness
trouble swallowing
nasal congestion
Anaphylaxis GI
N/V
stomach pain
cramps
diarrhea
Anaphylaxis cardiovascular
dizziness/lightheadedness (d/t decreased cerebral perfusoin)
pale/blue color
weak pulse
fainitng
shock
reduced LOC
*histamine –> widespread vasodilation –> reduced BP
Anaphylaxis neurological
fainting
anxiety
impeding doom
Anaphylaxis other
uterine cramps
ASK approach
A = acknowledge concern
S = steer conversation
K = provide knowledge
Serological screening
screen for antibodies –> indicate immunity/ previous exposure
false positives/negatives
may not be actionable/beneficial
Sensitivity
ability of test to detect if someone is positive for x
Specificty
ability of test to detect if someone is negative for x
Positive predictive value
ability of test to correctly identify positive cases
T-cell dependent immunity
Protein antigens
Cytotoxic t cells & b cells responding to protein
T-cell independent immunity
Polysaccharides
B-cells do not require t-helper cells but do not produce memory cells
Microbial antigens
virus
bacteria
funghi
protozoa
parasites
Non-microbial antigens
plant pollen
poison ivy
resin
insect venom
organ transplant
Molecular antigen
proteins (primary)
polysaccharide
T-cell independent response
plasma cells mainly produce IgM antibodies
T-cell dependent response
plasma cells mainly produce IgG antibodies
T-cell activation
1) TCR binds with antigen epitope on the MHCII/MHCI complex
2) CD4/CD8 bind to ANOTHER site on the MHC complex –> activation
TCR
T-cell receptor
Types of helper T-cells
TH1
TH2
TH17
**determined by cytokines released by APC
How do helper T-cells activate other immune cells?
release of cytokines
Benefits of live vaccines
more comprehensive immune response –> cellular/humoral immunity
How are live vaccines produced
1) genetic manipulation
2) long-term culturing in an unnatural host –> reduce affinity, promote mutations
How are inactivated vaccines made
whole pathogens that have been killed/inactivated using heat, chemicals, radiation
What are subunit vaccines
key antigens of a pathogen are isolated
How are subunit vaccines made
1) chemical degradation
2) genetic engineering
Conjugate vaccine
protein + capsule polysaccharide
T-cell independent immunity –> antibodies that opsonize capsule of pathogens
Toxoid vaccine
inactivated bacterial toxins –> humoral immunity
Immune responses by time
ubiquitous 0-4 hrs
induced 4 hrs-4 days
adaptive 10-14 days
Immune responses by type
first line –> prevent microbes from entering
second line –> target microbes entering tissue
third line –> lymphocytes
Types of acquired immunity
vaccinations
immunoglobulins
breast milk
placenta antibodies
Antigen definition
anything that can be recognized by lymphocytes/antibodies
Immunogen definition
specific antigens that induce an immune response
What molecule is most immunogenic?
proteins
Recombinant pathogen
yeasts/plants engineered to make pathogen protein
Phase I clinical trial
30-50 people
Phase II clinical trial
200-400 people
Phase III clinical trial
3000+ people
Canadian pediatric society recomendations
1) do not dismiss vaccine refuses
2) presumptive approach > participatory approach
3) simple, clear language
4) address fear of pain/distress head on
5) reinforce community protection is insufficient
Herd immunity
disease control by vaccinating majority of population to prevent spread of disease. important to protect people who cannot get vaccinated/immunocompromised
