Acquired Immunity Quiz

Study Notes

Acquired Immunity

Acquired immunity can be active or passive.
Active immunity is the stimulation of the immune system to produce antibodies against a particular infectious agent.
Passive immunity is developed by antibodies that are produced outside and then introduced into the body.
Naturally acquired active immunity comes from infections encountered in daily life.
Artificially acquired active immunity is stimulated by exposure to specific foreign macromolecules through vaccines.
Naturally acquired passive immunity refers to antibodies transferred from mother to fetus across the placenta and to newborn in colostrum and breast milk.
Artificially acquired passive immunity is the transfer of antibodies formed by an animal or human to an individual to prevent or treat infection.

Active Immunization

A person acquires immunity or resistance to an infectious disease either naturally or through induction.
Active immunization leads to long-lasting memory immune cells.
Active immunization may be reactivated quickly by a recurrence of the infection or by revaccination.
The protective response of active immunization takes time to establish, which makes it inefficient as a post-exposure remedy.
Active immunization may not be suitable for protection of immunocompromised or immuno-deficient individuals.

Vaccine Types

Inactivated vaccines use the killed version of the germ that causes a disease.
- Examples of diseases that can be protected against using inactivated vaccines include: Hepatitis A, Flu, Polio and Rabies.
Live-attenuated vaccines use a weakened form of the pathogen that causes a disease.
- One or two doses of most live vaccines can give a lifetime of protection.
- People with weakened immune systems should talk to their health care provider before receiving this type of vaccine.
- Examples of diseases that can be protected against using live vaccines include: Measles, Mumps, Rubella, Rotavirus, Smallpox, Chickenpox, Yellow Fever.
Messenger RNA (mRNA) vaccines make proteins in order to trigger an immune response.
- mRNA vaccines are used to protect against COVID-19.
- mRNA vaccines have several benefits compared to other types of vaccines, including shorter manufacturing times and no risk of causing disease.
Subunit, recombinant, polysaccharide, and conjugate vaccines use specific pieces of the pathogen.
- They can be used on almost everyone who needs these vaccines, including people with weakened immune systems.
- Examples of diseases that can be protected against using these types of vaccines include: Hib (Haemophilus influenzae type b) disease, Hepatitis B, HPV (Human papillomavirus), Whooping cough, Pneumococcal disease, Meningococcal disease, Shingles.
Toxoid vaccines use a toxin made by the pathogen that causes a disease.
- Like some other types of vaccines, booster injections may be needed to get ongoing protection.
- Examples of diseases that can be protected against using toxoid vaccines are: Diphtheria, Tetanus.
Viral vector vaccines use a modified version of a different virus to deliver protection.
- Examples of diseases that can be protected against using viral vector vaccines are: COVID-19, Ebola.

Passive Immunization

Passive immunization involves giving antibodies to an organism or a toxin produced by an organism.
Passive immunization is used for people who cannot synthesize antibodies, have been exposed to a disease that they are not immune to, or have a disease and the effects of the toxin must be ameliorated.
Passive immunization does not induce natural immunity.

Human Immune Globulin (IG)

IG is a concentrated antibody-containing solution prepared from plasma obtained from normal donors.
It consists primarily of IgG, but may also contain trace amounts of IgA, IgM.
It is stable for many months if stored at 4° C.
The half-life of IG in the circulation is about 3 weeks.

Types of IG

Intravenous immune globulin (IVIG)
Intramuscular immune globulin (IMIG)
Subcutaneous immune globulin (SCIG)
Hyperimmune globulin

### Advantages of Passive Immunization

Passive immunization is short-lived, acts quicker than active immunization, and produces an immune response within hours or days of administration.
Passive immunization can override a deficient immune system.

### Disadvantages of Passive Immunization

Antibodies are costly to produce.
Antibodies from animals can cause serious allergic reactions.
Antibodies must be administered via intravenous injection, which can be a complicated procedure.
The immunity conferred by passive immunization is short-lived.

### Advantages of Active Immunization

Active immunization leads to a longer-lasting immune response than passive immunization.

Disadvantages of Active Immunization

The protective response takes time to establish, which makes it inefficient as a post-exposure remedy.
Active immunization may not be suitable for protection of immunocompromised or immuno-deficient individuals.