Chapter 8 Passive Immunization

Question 1

Define passive immunization.

Answer 1

Transfer of antibodies to an unprotected individual for the prevention or treatment of disease.

Question 2

Who first demonstrated the principle of passive immunization? Against which disease?

Answer 2

Emil von Behring, immunological treatment of diphtheria.

Question 3

Name five (5) deadly diseases for which passive immunization was the only treatment before antibiotics were developed.

Answer 3

1. Diphtheria.
2. Scarlet fever.
3. Bacterial meningitis.
4. Bacterial pneumonia.
5. Tularemia.

Question 4

Describe the main form of passive immunization in humans.

Answer 4

Transfer of IgG antibodies from the blood of the immune mother to the foetus, through the placenta.

Question 5

Name two (2) diseases whose clinical presentation is delayed in infants by passive immunization from the mother.

Answer 5

1. Severe combined immunodeficiency (SCID), which results in lack of functional T and B lymphocytes.
2. Agammaglobulinemia, which results in lack of functional B cells.

Question 6

How long does passive immunization from mother to newborn typically lasts?

Answer 6

Approximately 6 months.

Question 7

With what class of vaccines do maternal antibodies interfere with? Name the two (2) main affected vaccines.

Answer 7

Live attenuated vaccines.

1. MMR (measles-mumps-rubella).
2. Rotavirus.

Question 8

Name two (2) diseases against which active immunization of the mother is recommended in order to protect the future newborn by passive immunization.

Answer 8

1. Influenza.
2. Pertussis.

Question 9

Name the four (4) categories of passive immunization products currently in use.

Answer 9

1. Standard human immunoglobulins.
2. Human hyperimmunoglobulins.
3. Animal-derived immunoglobulin products.
4. Monoclonal antibodies.

Question 10

Name four (4) diseases against which standard human immunoglobulins can be used.

Answer 10

1. Hepatitis A.
2. Measles.
3. Varicella.
4. Rubella.

Question 11

Name eight (8) diseases against which hyperimmunoglobulins can be used.

Answer 11

1. Inhalation anthrax (therapeutic).
2. Infant botulism (therapeutic).
3. CMV infection (prophylaxis in organ transplant).
4. Hepatitis B (prevention and post-exposure prophylaxis).
5. Rabies (post-exposure prophylaxis).
6. Tetanus (prophylaxis or therapeutic).
7. Smallpox.
8. Varicella (post-exposure prophylaxis in high-risk groups).

Question 12

Name four (4) therapeutic uses of animal-derived immunoglobulin products.

Answer 12

1. Animal bites (black widow spider, scorpion, rattlesnake).
2. Botulism (bivalent or heptavalent).
3. Diphtheria.
4. Digoxin toxicity.

Question 13

Name the two (2) main animal sources of immunoglobulin products.

Answer 13

1. Equine products.
2. Ovine products.

Question 14

Name the three (3) main monoclonal antibodies and their therapeutic uses in infectious diseases.

Answer 14

1. Palivizumab (RSV infection).
2. Raxibacumab (inhalation anthrax).
3. Casirivimab + imbdevimab (SARS-CoV-2 infection).

Question 15

Name two (2) advantages of polyclonal antibodies.

Answer 15

1. Specificity against multiple epitopes.
2. Multiple isotypes with different effector functions.

Question 16

Name four (4) disadvantages of polyclonal antibodies.

Answer 16

1. Low specific activity.
2. Broad variation in potency.
3. Limited availability.
4. Biohazard risk of human blood products.

Question 17

Name two (2) advantages of monoclonal antibodies.

Answer 17

1. High specific activity.
2. Standardized potency.
3. Unlimited availability.
4. Minimal biohazard potential.

Question 18

Name three (3) disadvantages of monoclonal antibodies.

Answer 18

1. Monovalent (single epitope) specificity.
2. Single isotype.
3. Potential to select for escape mutants.

Question 19

Name three (3) reasons why IgM are not suitable for passive immunization.

Answer 19

1. Confined to intravascular space.
2. Low affinity.
3. Short half-life (5 days).

Question 20

Name three (3) reasons why IgG is considered the best isotype for passive immunization.

Answer 20

1. Longer half-life compared to other types (21 days).
2. Capacity to enter nonlymphoid tissues.
3. Capacity to penetrate mucosal sites of infection.

Question 21

Name the two (2) determinants of clinical protection by passive immunization.

Answer 21

1. High titer of specific antibodies.
2. Early timing of antibody transfer in the course of the disease.