Principles and Types of Vaccination

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Questions and Answers

What characterizes active immunization?

Immediate immunity without the involvement of the immune system

The administration of preformed antibodies

The immune system's passive response to pathogens

Induction of proliferation of antigen-reactive T and B cells (correct)

How is passive immunization primarily achieved?

By stimulating the immune system to produce its own antibodies

Through the transfer of preformed antibodies from one individual to another (correct)

By using vaccines to trigger an immune response

Through the natural infection process

Which of the following statements about the immune system's role in passive immunization is accurate?

The immune system engages in a delayed response to pathogens.

The immune system produces T cells, which are then transferred to the recipient.

The immune system is inactive, relying solely on external antibodies. (correct)

The immune system is entirely responsible for generating the antibodies.

What is the result of the active immunization process?

Formation of protective antibodies through an active response Signup and view all the answers

Which term describes antibodies that are preformed and transferred to a recipient?

Antiserum Signup and view all the answers

What is the primary source of the antibodies used in this product?

Animal sources, mainly horses Signup and view all the answers

What is a defining characteristic of monoclonal antibodies?

They are produced from a single clone of B cell. Signup and view all the answers

Which two conditions can be treated with this type of product?

Botulism and diphtheria Signup and view all the answers

Why are monoclonal antibodies considered advantageous in treatment?

They offer specificity against one or closely related antigens. Signup and view all the answers

What limitation do monoclonal antibodies have compared to polyclonal antibodies?

They target a specific antigen rather than multiple antigens. Signup and view all the answers

Which of the following vaccines belongs to the live-attenuated category?

Measles Signup and view all the answers

Which type of vaccine is specifically derived from inactivated pathogens?

Inactivated Signup and view all the answers

What is a distinguishing characteristic of active immunity compared to passive immunity?

Active immunity lasts for many years. Signup and view all the answers

Which of the following is NOT an example of a toxoid vaccine?

Hepatitis B Signup and view all the answers

Which vaccine type is characterized by its conjugation of polysaccharides with proteins?

Conjugate polysaccharide-protein Signup and view all the answers

What does the term 'immunologic memory' refer to?

The ability to recall previous infections. Signup and view all the answers

What category does the Hepatitis A vaccine fall under?

Inactivated Signup and view all the answers

Which aspect is primarily targeted by active immunity?

Antigen-specific humoral response. Signup and view all the answers

Which of the following conditions can active immunity help prevent or treat?

Certain infections through natural exposure. Signup and view all the answers

In what way does active immunity relate to autoimmune diseases?

It can cause the immune system to become hyperactive. Signup and view all the answers

What type of molecular structure is found in the vaccine for Neisseria meningitidis?

Purified capsular polysaccharides Signup and view all the answers

Which of the following statements accurately describes Neisseria meningitidis in relation to bacterial meningitis?

It is a common cause of bacterial meningitis. Signup and view all the answers

Which pathogens have shown protective immunity through DNA vaccines in animal models?

Influenza and rabies viruses Signup and view all the answers

What is the primary component of the vaccine developed for Neisseria meningitidis?

Purified capsular polysaccharides Signup and view all the answers

What is a key feature of DNA vaccines based on animal model tests?

They have shown effectiveness against multiple viruses. Signup and view all the answers

What role do capsular polysaccharides play in the immune response to Neisseria meningitidis?

They trigger an adaptive immune response by acting as an antigen. Signup and view all the answers

In the context of DNA vaccines, what is primarily being tested in animal models?

The ability to induce protective immunity. Signup and view all the answers

Which feature of the Neisseria meningitidis vaccine allows for its effectiveness in preventing infection?

The inclusion of polysaccharide capsules from the bacteria. Signup and view all the answers

Which of the following statements is true regarding the use of DNA vaccines?

They have been shown to induce protective immunity against certain viruses. Signup and view all the answers

The effectiveness of DNA vaccines in animal models is primarily attributed to their ability to:

Induce durable cellular and humoral immunity. Signup and view all the answers

Study Notes

Principles of Vaccination

Vaccination is the process of introducing a weakened or inactive form of a pathogen into the body to stimulate an immune response.
Immunity is the body's ability to recognize and eliminate foreign substances.
Immunization is the process of inducing immunity against a disease.
Passive immunity is acquired by receiving pre-formed antibodies, either naturally (e.g., from mother to child) or artificially (e.g., by injection of antibodies).
Active immunity is acquired by the body's own immune response to a pathogen, either through natural infection or vaccination.

Types of Vaccines

Live attenuated vaccines: Weakened forms of a living pathogen.
- Examples: Measles, mumps, rubella (MMR), varicella (chickenpox), influenza.
- Microorganisms are weakened/attenuated, losing their ability to cause significant disease but retaining their capacity for transient growth within the inoculated host.
- The first vaccine developed (by Jenner), inoculating humans with vaccinia (cowpox) to confer smallpox immunity.
- Attenuation can be achieved by growing pathogenic bacteria or viruses in abnormal culture conditions to select better growth suited mutants.
- Example: BCG is an attenuated strain of Mycobacterium bovis.
- Live attenuated vaccines replicate in the host and induce both humoral and cell-mediated immunity.
- Live attenuated vaccines require only a single immunization.
Inactivated vaccines: Killed forms of a pathogen.
- Examples: Inactivated polio, hepatitis A, influenza, rabies.
- Pathogens are treated with heat or chemicals to kill it, making it incapable of replication but able to induce an immune response.
- Maintaining structure of epitopes on surface antigens is important. Heat inactivation is often unsatisfactory because it denatures proteins. Chemical inactivation is more successful.
- Examples: The Salk polio vaccine was produced by formaldehyde inactivation.
- Killed vaccines often require repeated boosters as they don't replicate.
- Produce predominantly humoral response and are less effective than attenuated vaccines in inducing cell-mediated immunity.
- Increased safety compared to live attenuated vaccines.
Subunit vaccines: Use specific antigenic parts of a pathogen.
- Examples: Hepatitis B, some pneumococcal vaccines.
- Contain only specific, purified macromolecules derived from the pathogen.
- Contain only the necessary antigenic parts of the pathogen to elicit a protective immune response.
- Common subunit vaccines include inactivated exotoxins, capsular polysaccharides/surface glycoproteins, and key recombinant proteins.
Toxoid vaccines: Inactivated toxins produced by bacteria.
- Examples: Tetanus, diphtheria.
- Inactivated exotoxins are treated with heat or chemicals.
- Unable to cause disease but stimulate the production of antitoxin antibodies, neutralizing their effects.
Capsular polysaccharide vaccines: Purified capsular polysaccharides of bacteria.
- Examples: Pneumococcal, meningococcal, Haemophilus influenzae type b (Hib).
- The virulence of some bacteria depends on their antiphagocytic polysaccharide capsule.
- Coating the capsule with antibodies/complement increases phagocytosis by macrophages and neutrophils.
Recombinant vector vaccines: Use a modified pathogen as a vector to deliver antigens.
- Examples: Some yellow fever vaccines.
- Live attenuated vaccines that deliver antigens, but avoid reverting to pathogenic forms.
- Individual genes encoding key antigens are introduced into attenuated viruses/bacteria, enabling replicating organisms to express pathogen genes, eliminating reversion potential.
DNA vaccines: Introduce pathogen genes into cells to produce antigens.
- Plasmid DNA encoding antigenic proteins is injected directly into muscle tissue.
- DNA either integrates into chromosomal DNA or exists episomally.
- Often taken up by dendritic cells/muscle cells in the injection area.
- Induces protective immunity against various pathogens.
- Follow-up booster shots or supplementary DNA may enhance immune response.
- Advantages: no denaturation, exact antigen expression, no refrigeration needed, simultaneous manufacture of multiple vaccines, successful human trials underway.

Passive Immunity

Homologous pooled human antibody (immune globulin): IgG antibody fraction from many donors. Used for prophylaxis of hepatitis A and measles.
Homologous human hyperimmune globulins: Antibody products with high titers of specific antibodies. Used for hepatitis B, rabies, and tetanus.
Heterologous hyperimmune serum (antitoxin): Produced in animals (e.g., horses). Contains antibodies against a specific antigen. Used for botulism and diphtheria.
Monoclonal antibody: Produced from a single B cell clone. Contains antibodies against only one or closely related group of antigens. Used in cancer treatment, transplant rejection, and autoimmune disease treatment.

Active Immunity

Stimulation of the immune system to produce antigen-specific antibody responses.
Unlike passive immunity, active immunity lasts for extended periods, with persistence known as immunologic memory.

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Description

This quiz covers the fundamentals of vaccination, including the concepts of immunity, immunization, and the different types of vaccines. Test your knowledge on live attenuated vaccines and their importance in preventing diseases. Learn about how the body acquires immunity through vaccination and natural infection.