BIO-336 Ch. 11

Toxoid

An inactivated toxin that is no longer poisonous but still immunogenic

Example of a toxoid

Tetanus toxoid.

Describe the mechanism of a conjugate vaccine.

1. B-cell binds polysaccharide conjugated to protein.
2. Complex is internalized and processed.
3. Peptide is presented on MHC-II to CD4 T-cells.
4. T-cells activate B-cell class switching to IgG and memory development.

How did the Hepatitis B vaccine production change over time?

It was first harvested from humans, but is now produced using yeast through recombinant technology.

How is Active Artificial immunization achieved?

Through vaccination, where a killed or attenuated agent is introduced to stimulate an immune response without causing full disease.

How is Active Natural immunization achieved?

Through natural infection with a pathogen, leading to the development of the host's own immune response and memory.

How is Passive Natural immunization achieved?

Through colostrum (breast milk) or transplacental transfer of antibodies from mother to fetus.

In 2012, how many doses of vaccines were recommended for a child by the age of 6?

49 doses of 14 different vaccines.

In vaccine terminology, what is reversion?

The process where a live attenuated vaccine strain mutates back into its virulent form, potentially causing disease.

List the components of the DPT (TDaP) vaccine.

1. Diphtheria (bacterial toxoid)
2. Pertussis (killed or acellular)
3. Tetanus (bacterial toxoid)

Name at least five vaccines developed or improved by Maurice Hilleman.

1. Hepatitis A
2. Hepatitis B
3. Measles
4. Mumps
5. Rubella
(Others include: Varicella-zoster, Hib, and Influenza)

Name the specific attenuated strains used in the MMR vaccine.

1. Measles: Moraten
2. Mumps: Jeryl Lynn
3. Rubella: Wistar RA 27/3

Name three diseases for which Passive Artificial immunization is commonly used after suspected exposure.

1. Rabies
2. Tetanus
3. Hepatitis

What are four reasons why live attenuated strains have reduced virulence?

1. They grow poorly at body temperature.
2. They do not replicate well in human cells.
3. They are susceptible to normal immunity.
4. They replicate at sites that do not cause disease.

What are some common economic or political barriers to effective vaccination?

1. Production problems
2. Neglect of vaccination opportunities
3. Religious preferences
4. High development costs

What are the benefits of live vaccines compared to inactivated ones?

1. Robust and long-lived immunity.
2. Natural progression of cellular response (TH1 then TH2).
3. Strong memory response.

What are the characteristics of Inactivated (nonliving) vaccines?

1. They are generally safe (no risk of reversion).
2. The agent is killed (heat or formalin).
3. They often require adjuvants and boosters.

What are the four main categories of Passive and Active Immunization?

1. Passive Natural
2. Passive Artificial
3. Active Natural
4. Active Artificial

What are the risks/concerns regarding live vaccines?

1. Virulence in pregnancy or immune suppressed patients.
2. Risk of reversion to virulent forms.
3. Viability must be maintained (cold chain).

What are the three primary factors listed that affect the spread of an infectious disease?

1) Density of susceptible individuals (herd immunity)
2) Range of transmission
3) Quarantine

What are the two main types of living vaccines?

1. Live attenuated strains (e.g., MMR)
2. Hybrid viruses

What are VLP vaccines?

Virus-Like Particle vaccines; they mimic the virus structure but lack genetic material, making them non-infectious but highly immunogenic.

What attenuated strain is used for the Varicella-zoster (chickenpox) vaccine?

The Oka strain.

What characterizes Passive Artificial immunization?

The transfer of antibodies (Immune Serum Globulin - ISG) from a human or animal source to a patient to provide immediate but short-term protection.

Why are carbohydrates (polysaccharides) usually poor immunogens?

They do not elicit T-cell help, resulting only in IgM production without immunological memory.

Who was Maurice Hilleman and what was his major contribution to medicine?

He was a medical scientist (1920–2005) credited with developing over 40 vaccines; The Times UK stated "he did as much for the human race as any medical scientist."

Which two major diseases have been effectively eliminated through vaccination?

1. Smallpox (eliminated from the planet)
2. Polio (eliminated from the Western world)

Which organism is used to produce the BCG (Bacillus Calmette-Guerin) vaccine for Tuberculosis?

Mycobacterium bovis.

Which class of antibody is capable of transplacental transfer for natural passive immunity?

IgG (IgM cannot cross the placenta).

Which Active Artificial vaccine is unusual because it can be given after exposure and still provide protection?

The Rabies vaccine.

What is unique about the Lyme disease vaccine?

The antibody (ab) is generated against an antigen (OspA) that is expressed on the organism while it is still inside the tick.

What is the significance of the J-chain in antibody structure?

It is a protein that holds together multimers of antibodies, specifically IgA (dimers) and IgM (pentamers).

What is the role of the ACIP?

The Advisory Committee on Immunization Practices; they provide the official recommendations for vaccine schedules in the US.

What is the primary goal of vaccination?

To block the spread of disease by reducing the number of susceptible individuals in a population.

What is the etymological origin of the word vaccine?

It comes from vaccinia virus (the cowpox virus), which was used to protect against smallpox.

Sabin polio vaccine

Live oral vaccine

Salk polio vaccine

Inactivated (killed) injectable vaccine.

What is serum sickness?

A hypersensitivity reaction that can occur when animal antibodies (e.g., equine sources) are used for artificial passive immunization.

What is RhoGam and what type of immunization does it represent?

It is a Passive Artificial immunization used to prevent hemolytic disease of the newborn (Rh incompatibility).

What is interference in vaccination, and which example is provided?

When one vaccine blocks the effectiveness of another; for example, Rubella immunization can block Polio immunization.

What is Alum in the context of vaccination?

An adjuvant used with inactivated vaccines to enhance the immune response.

What is a conjugate vaccine?

A vaccine made by linking a carbohydrate antigen to a protein carrier to make it more immunogenic and recruit T-cell help (e.g., Hib, Pneumococcus).

Herd immunity

When a high percentage of a population is vaccinated, the spread of disease is limited, which indirectly protects those who cannot be vaccinated (e.g., pregnant women, chemo patients).

What does the "secretory component" allow IgA to do?

It allows IgA to traverse epithelial cells to reach mucosal surfaces (tears, saliva, gut).

What does DISC stand for in future vaccine technology?

Defective Infectious Single Cycle vaccines.

What characterizes Passive Artificial immunization?

The transfer of antibodies (Immune Serum Globulin - ISG) from a human or animal source to a patient to provide immediate but short-term protection.