Active Immunity Flashcards
Two kinds. of acquired immunity
Natural and artificial
Two kinds of natural immunity
Active immunity: As consequence of a person developing own immune response to a microbe
Passive immunity: In consequences of one person receiving performed immunity made by another person (by breast feeding, the IgA)
How does IgA funciton in breast milk
The IgA agglutigates to pathogens present IN the breast milk before it even gets to the baby
Two kinds of artificial immunity
Active immunity: Antibodies produced outside the body, introduced to the body bc a person has been exposed to a pathogen (Only helps if introduced in early stages of infection
Passive immunity:
Antibodies = antiserum
Produced by animal, antibodies are purified and then injected to person\
Vaccination
Process of introducing antigen into body - route of administration may vary
Immunization
What results from vaccinations stimulating immunity
Vaccine induces Abs production nand activated Cell-mediated immunity callrs to protect host from future infection
Infant/childhood immunizations include booster doses for
tetanus, diphtheria, whooping cough and polio
At what age are boosters first given
Kindergarten
What booster is given following any deep injury
Booster tetanus toxoid
Four major types of vaccines
Whole cells (live attenuated or inactivated-killed)
Acellular or subunit (part of the cell, NOT whole thing) : (toxoid (part of toxin), recombinant vaccine)
Conjubated (Two components, joined together) (capsule+protein) - greater stimulation of the immune system (Haemophilus influenza type B vaccine)
Nucleic acid: DNA or RNA (covid19 vaccine)
Attentuated vaccines
(Live but avirulent)
Longer term protection w/o booster, effective, closely mimic actual infection
Disadvantages: Potential stronger sideaffects, virus occasionally reverts to the toxic type (rare)
Examples of attentuated vaccines
viral vaccines: Measella, rubella, poli, chickpoc
Bacterial vaccines: TB, and typhoid
Two types to administer a whle cell vaccine
Attentuated (Live but avirulent)
Inactivated/killed
Inactivated vaccine
Heat or chemical killing/inactivation (chemicals: formalin or phenol)
Less effective, require boosters
Whole organism used
Advangtages: Produces several types of Antibodies, some more effective than others
Examples of inactivated vaccines
Viral vaccines: Rabies (og), polio (salk), influenza
Bacterial vaccine: whoopign cough, cholera, pneumococcal pneumonia
Acellular or subunit vaccines
Antigenic fragments of a pathogen that best stimulates an immune response
Capsular polysacchardie (part of capsule)
Surface antigenic proteins
Toxoid(inactivated toxin)
How are subunit vaccines produced
by genetic modification technique
Example of acellular vaccine
Heb B Vaccine
Nucleic Acid vaccine
DNA/RNA is artificially produced, and purity is assured
Can be expressed for extended times with good immunological memory
Several genes can be mixed and injected as one vaccine
DNA/RNA sequences can be produced cheaply and very quickly
Genes can be quickly isolated from any organism and vaccines can be generated
Bare bones type of vaccines (minimum stuff required ot make a vaccine)
Example of DNA vaccines
Covid 19
Why do some vaccine- preventable diseases persist?
Microbes persist in the environment - cannot be eliminated
Some vaccine formulations need extra boosters to remain effective
Avoidance of vaccination
Lower rate of vaccination due to poverty and lack of health infrastructure
How many phases of clinical trials
4
Phase 1 goal to determine
Is the new drug/treatnent safe
Phase 1 involves
Involves 10-80 volunteers
Volunteers closely monitored for toxicity, side effects, dosagel levels, route of administration (not necessarily looking at efficacy)
Abt 70% of drugs proceed to phase 2
Goal of phase 2
Does the new drug/treatment work
Phase 2 involves
100-300 volunteers
Volunteers receive dose determined to be most effective in phase 1
May last up to two years and new combinations of drugs also tested
Although more people invovled still may not pickup all the risks
Therw is need foro some people to have the condition being teated
Abut 30% of drugs/treatments proceed to phase 3
Phase 3 goals
Is new drug/treatment better than what we have
Phase 3 involves
Involves 1000s-10,000s (across countries)
Volunteers randomly assigned to groups
Double blind studies used (people administering and receiving treatment don’t know if recieving treatment or placebo)
May last several years
Although more people involved, still may not pick up all the risks
If successful, durg/treatment manufacturers ay then apply for approval
25-30% proceed to phase 4
Emergency use authorization
Trials have been done and proven to work, during crisis, they can be used before approval
Phase 4 goal
What else can we learn abt drug/treatment?
Phase 4 involves
Involvese collecting data as the drug/treatment is rolled out
Since drug is now being administerd to large population, some rare side effects may apperar (blood clots in Astrzeneca)
What are long term side effects
Phase 4 clinical trials are generally safest (drug has already been extensively studeied)
When could an emergecy use authorization occur?
Phase 3 or even 2
Adjuvants
Nontoxic materials added to vaccines to enhance immunogenicity of highly purified antigens
Increases the effectibenes of vaccines
Multivalent DPT or DPT-polio vaccine uses aluminum salts
Some adjuvants can cause allergic reactions
Examples of adjuvants
Aluminum salts, phosphates, oil-and water emulsion
Multivalnet vaccine benefits
Individuals vaccines often combined
Reduces number of injections children are subjected to
Comon ultivalent vaccine in Canada
Dipttheria (d), and acellular Pertussis and Tetanus toxoid (T) - DaPT
Salk polio vaccine added - DaPT - polio vaccine
Pentavelent vaccine DaPT-polio-Hib
