Active & Passive Immunity/ Vaccinations Flashcards
Which kind of immunity does receiving preformed antibodies impart?
Passive immunity
- passive because antibodies are pre-formed, body doesn’t need to make them ‘actively’ against antigen
- transfer of active humoral immunity (antibodies from B cells) from one individual to another
Which kind of immunity does exposure to exogenous antigens produce?
Active immunity
Which immunity takes longer to develop?
Active immunity
Which immunity develops rapidly?
Passive immunity
How long does passive immunity last?
Short-lived protection—around 3 weeks to 4 months
because of short span of antibodies (half-life = 3 weeks)
How does a person get passive immunity?
Maternal/ Natural passive immunity
is immunity passed along from mother to child
-trans-placental IgG
-breast milk IgA
Artificial passive immunity
comes from injected antibodies created within a different person or an animal. These antibody-containing preparations are termed antiserum
-rabies vaccine
-snake antivenom
-humanized monoclonal antibody (blood transfusion)
Immunity gained by breast milk is which type of immunity?
Maternal/ Natural passive immunity
What are examples of artificial passive immunity?
Antitoxins
- rabies vaccine
- snake antivenom
Humanized monoclonal antibodies
-abciximab
How does a person get active immunity?
Natural immunity
-Natural infection
Artificial/ Vaccine-induced immunity
- vaccines
- toxoids
How long does active immunity last?
Long-lasting protection (memory)
years even entire life-time
A chickenpox infection will impart which type of immunity to a child?
Active immunity
What are examples of natural passive immunity?
- trans-placental IgG
- breast milk IgA
maternal/ natural passive immunity
is immunity passed along from mother to child
Which immunity develops after exposure to tetanus toxin?
Passive immunity
Preformed antibodies are administered to unvaccinated patients after exposure to which type of toxins?
Which cells provide these antibodies?
What type of immunity will this provide?
Tetanus
HBV
Varicella
Rabies virus
Botulinum toxin
Diphtheria toxin
(To Heal Very Rapidly Before Disease)
B cells
Passive immunity
Which immunity involves both humoral and cell mediated immunity?
Active immunity
vaccination
What is secondary immune response?
The first exposure leads to primary response (formation of long-lasting memory cells) and incase of a subsequent exposure to same pathogen later, a much faster and stronger secondary response is established.
(eg “booster” shots) evokes a secondary response (anamnestic, memory, or booster response) that is stronger, peaks in 2–7 days, and last months to years
The main antibody is of the IgG type
Which type of immunity is not suitable for immunocompromised patients?
Why?
Active immunity
Because even live attenuated vaccines (active immunity) can cause significant disease (there is potential for live organism to revert back to virulent form and the immunocompromised individual cannot form an adequate immune response)
Which type of conditions benefit from both active & passive immunity?
Hepatitis B
Rabies exposure
What is live attenuated vaccine?
Which type of immune response?
Microorganism rendered nonpathogenic but retains capacity for transient growth within inoculated host.
Induces cellular and humoral responses (Active artificial immunity)
Give example of how passive immunity can be utilized as a treatment?
- Gamma-globulin (IgG) injection for HIV patients
- Hepatitis B antibodies to prevent infection even after exposure
(expensive because the half-life is ~30 days)
What is advantage of live attenuated vaccine?
Induces strong, often lifelong immunity
What is disadvantage of live attenuated vaccine?
may revert to virulent form
Contraindicated in pregnant and immunodeficient patients
What are examples of live attenuated vaccines?
Attention Teachers Please Vaccinate SMALL Beautiful Young Infants with MMR Regularly
Adenovirus (nonattenuated, given to military recruits)
Typhoid (Ty21a, oral)
Polio (Sabin)
Varicella (chickenpox)
SMALLpox
BCG (TB)
Yellow fever
Influenza (intranasal)
MMR
Measles Mumps Rubella
Rotavirus
In what condition can MMR and varicella vaccines be given to people living with HIV without evidence of
immunity?
If CD4 cell count ≥ 200 cells/mm3
What type of immunity do vaccinations provide?
Active immunity (Humoral and/or cell-mediated immunity)
Which type of vaccine in which pathogen is inactivated by heat or chemicals?
Killed or inactivated vaccine
Killed or inactivated vaccine provide which type of immune response?
Humoral immunity
What is disadvantage of killed vaccine?
- Weaker immune response
- Booster shots usually required
What are examples of killed or inactivated vaccine?
A TRIP could Kill you
Hepatitis A
Typhoid (Vi polysaccharide, intramuscular)
Rabies
Influenza
Polio (SalK)
What is a subunit vaccine?
Advantages?
Disadvantages?
Examples?
Vaccine with purified parts of the pathogen that are antigenic (elicit immune response)
-doesn’t contain the whole pathogen, unlike live attenuated or inactivated vaccine, but contains only the antigenic parts (proteins, polysaccharides or peptides)
Advantages
- safer, more stable (lower chance of adverse reactions)
- well-established technology
- suitable for immunocompromised individuals
- can withstand changes in conditions (temperature, light exposure, humidity)
Disadvantages
- Complex & expensive to manufacture
- Weaker immune response (require adjuvants and booster shots & time to examine which antigenic combinations work best)
Examples
HBV (antigen = HBsAg), HPV (types 6, 11, 16, and 18), acellular pertussis (aP), Neisseria meningitidis (various strains), Streptococcus pneumoniae, Haemophilus influenzae type b.
What is a subunit vaccine?
Advantages?
Disadvantages?
Examples?
Vaccine with purified parts of the pathogen that are antigenic (elicit immune response)
-doesn’t contain the whole pathogen, unlike live attenuated or inactivated vaccine, but contains only the antigenic parts (proteins, polysaccharides or peptides)
Advantages
- safer, more stable (lower chance of adverse reactions)
- well-established technology
- suitable for immunocompromised individuals
- can withstand changes in conditions (temperature, light exposure, humidity)
Disadvantages
- Complex & expensive to manufacture
- Weaker immune response (require adjuvants and booster shots & time to examine which antigenic combinations work best)
Examples
Protein subunit
- HBV (antigen = HBsAg)
- acellular pertussis (aP)
- HPV (types 6, 11, 16, and 18)
Polysaccharide subunit
- Neisseria meningitidis
- Streptococcus pneumoniae
Conjugate
-Haemophilus influenzae type b
What is a toxoid vaccine?
Examples?
Denatured (inactivated) bacterial toxin proteins with an intact receptor binding site. Stimulates the immune system to make antibodies without potential for causing disease (prevents disease but not infection)
toxoid: toxin like
DTaP
Diptheria, tetanus, acellular Pertussis
Clostridium tetani (tetanospasmin)
Corynebacterium diphtheriae (dipth toxin)
- remember point
tetanus: its symptoms are not caused by the Clostridium tetani bacterium, but by a neurotoxin it produces (tetanospasmin)
*Whole-cell pertussis vaccines contain the entire inactivated organism while acellular pertussis vaccines contain parts (subunits) including the pertussis toxin alone or with components such as filamentous haemagglutinin, fimbrial antigens and pertactin
Advantages of toxoid vaccine?
Disadvantages
Pros
- safe (cannot cause the disease & no possibility of reversion to virulence)
- cannot spread to unimmunized individuals (vaccine antigens are not actively multiplying)
- stable & long lasting (suitable for temperature, humidity and light)
Cons
- need an adjuvant and require several doses
- local reactions at the vaccine site are more common—(may be due to the adjuvant or a type III (Arthus) reaction: reaction results from excess antibody at the site complexing with toxoid molecules and activating complement by the classical pathway causing an acute local inflammatory reaction)
Which immunoglobulins do polysaccharide vaccines produce?
IgM
because inability of polysaccharide to activate Th cells which require protein to be activated
What are some of the risks associated with artificial (passive) immunotherapy?
-IgE antibodies (produced against foreign species antibodies) → systemic anaphylaxis
especially in patients with IgA deficiency (they have not encountered IgA before and they produce IgE after infusion with even human gamma globulins - therefore have to give IgA depleted globulins)
- IgG & IgM anti-isotype antibodies can be formed against foreign antibodies → complement-activating immune complex → type III hypersensitivity reactions
- IgG anti-allotype antibodies can be formed against minor polymorphic or other allotype immunoglobulins
