Immunology Overview and Vaccination History

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Questions and Answers

What does innate immunity primarily rely on for defense against pathogens?

B and T lymphocytes

Physical and chemical barriers (correct)

DNA rearrangement of receptors

Complex chemical signals

How quickly can innate immunity respond to a pathogen?

Within hours of encounter (correct)

Within days of exposure

Immediately upon pathogen recognition

Within weeks of initial exposure

Which type of immunity is characterized by a slower response and greater specificity?

Innate immunity

Passive immunity

Adaptive immunity (correct)

Cell-mediated immunity

What kind of receptors do B and T lymphocytes use in adaptive immunity?

Antigen-specific receptors Signup and view all the answers

What initiates the adaptive immune response after the initial barrier breach?

Recognition of antigens by innate processes Signup and view all the answers

What was the outcome for the chickens that had been previously exposed to the old bacterial culture?

They were completely protected from the disease. Signup and view all the answers

What is a defining characteristic of the adaptive immune response?

Ability to remember previous pathogens Signup and view all the answers

What term did Pasteur use to describe the weakened bacterial strain used for vaccination?

Vaccine Signup and view all the answers

What happens to T and B lymphocytes after they encounter an antigen?

They undergo selection and proliferation Signup and view all the answers

What is one limitation of the innate immune system?

Lack of specificity Signup and view all the answers

In which year did Pasteur first administer a vaccine to a human?

1885 Signup and view all the answers

Why was Joseph Meister's case significant in the history of vaccination?

He survived after being bitten by a rabid dog. Signup and view all the answers

What does the success of the rabies vaccine depend on after exposure?

Administration before symptoms appear. Signup and view all the answers

What was Louis Pasteur's primary hypothesis regarding the aging of bacterial cultures?

It weakened the virulence of pathogens. Signup and view all the answers

What institute did Pasteur open in 1887?

Pasteur Institute Signup and view all the answers

What significant aspect of Pasteur's work with vaccines was shown in his experiments?

Attenuated strains can provide immunity against diseases. Signup and view all the answers

What is one primary method for preventing the transmission of infectious diseases?

Access to clean water Signup and view all the answers

Which type of immunity is considered to be possessed at birth?

Innate Immunity Signup and view all the answers

Which of the following is true about passive immunity?

It is always present in an individual. Signup and view all the answers

What is a characteristic of innate immunity?

It is evolutionarily primitive. Signup and view all the answers

Which of the following diseases is unlikely to target expensive vaccination programs?

Common cold Signup and view all the answers

Which component of the immune response is also known as humoral immunity?

Adaptive Immunity Signup and view all the answers

What is a requirement for effective vaccination against infectious diseases?

Ability to establish immunologic memory Signup and view all the answers

Which type of immunity is characterized by being created and modified?

Adaptive Immunity Signup and view all the answers

What is a key characteristic of adaptive immunity?

It can distinguish subtle differences among antigens. Signup and view all the answers

What is produced by activated B cells during the primary immune response?

Plasma cells and memory cells Signup and view all the answers

What is the lag phase in a primary immune response?

The duration from antigen introduction to first antibody appearance Signup and view all the answers

What happens during a secondary immune response?

Memory cells convert directly into plasma cells upon activation. Signup and view all the answers

Why is it essential for the immune system to recognize self from nonself?

To prevent fatal reactions to self molecules. Signup and view all the answers

What role do plasma cells play in the immune response?

They create antibodies. Signup and view all the answers

What does immunologic memory allow for?

Life-long immunity after initial exposure to certain antigens. Signup and view all the answers

Which of the following statements about antibodies is true?

They can recognize two proteins differing by a single amino acid. Signup and view all the answers

What is primarily produced during the secondary immune response?

IgG antibodies Signup and view all the answers

How much more antibodies are typically produced in a secondary immune response compared to a primary response?

100 times more Signup and view all the answers

Which of the following best describes humoral immunity?

Mediated by secreted antibodies and extracellular fluids Signup and view all the answers

What is the primary function of cell-mediated immunity?

Activation of phagocytes and cytotoxic T-lymphocytes Signup and view all the answers

Which of the following is NOT a function of antibodies in humoral immunity?

Activation of T cells Signup and view all the answers

Which of the following statements regarding antibodies in secondary immune response is true?

They are produced without the need for T or B cell activation. Signup and view all the answers

What does affinity maturation refer to in humoral immunity?

The increase in affinity of antibodies for antigens Signup and view all the answers

How does cell-mediated immunity eliminate infected or cancerous cells?

By inducing apoptosis in affected cells Signup and view all the answers

Study Notes

Early Vaccination Studies Led the Way to Immunology

Louis Pasteur proved that ageing weakened the virulence of a fowl cholera bacterium.
He used this discovery to develop a vaccine (from Latin "vacca" meaning cow) in honor of Jenner's work with cowpox.
Pasteur successfully created a rabies vaccine for a young boy who had been bitten by a rabid dog.
Joseph Meister became a caretaker at the Pasteur institute, which was established in 1887 to treat rabies patients.

Immunology Is About More than Just Vaccines and Infectious Disease

Many infections are prevented by clean water, good hygiene, and nutrient-rich diets.
Some infections are self-limiting and treatable, and are unlikely targets for expensive vaccination programs, including the common cold and cold sores.
Some infectious agents are not suitable for vaccination due to a range of factors, including the number of molecular variants, the complexity of generating immunity, or the body's inability to establish adequate immune memory responses.

The Immune Response Is Composed of Two Interconnected Arms - Innate and Adaptive Immunity

Innate immunity comprises evolutionarily primitive mechanisms preventing infection or quickly eliminating common invaders.
It includes physical barriers and DNA-encoded receptors, recognizing common structures of many pathogens.
Adaptive immunity is more attuned to subtle molecular differences and relies on B and T lymphocytes.
It takes longer than innate immunity to mount an immune response but is more specific.

The Immune Response Is Composed of Two Interconnected Arms - Innate Immunity

Innate defenses include physical and chemical barriers, as well as DNA-encoded receptors recognizing common pathogen structures.
It also includes complement - a series of pre-existing serum proteins that initiate a cascade of labeling and destruction events against pathogens.

The Immune Response Is Composed of Two Interconnected Arms - Adaptive Immunity

Adaptive immunity is slower than innate immunity because fewer cells possess the perfect receptor for the specific antigen and because it relies on prior encounter and categorization of antigens.
T-cell and B-cell lymphocytes undergo selection and proliferation after an antigen encounter.
Adaptive immunity evolves in response to infection and displays four key attributes:
- Antigenic specificity. It can distinguish between even subtle differences among antigens.
- Diversity. It can recognize billions of unique structures on foreign antigens.
- Memory. It can confer lifelong immunity to many infectious agents after an initial encounter.
- Self/nonself recognition. It responds only to foreign antigens, preventing inappropriate responses to self molecules.

Adaptive Immunity – Primary & Secondary Response

Primary immune response occurs when an antigen is introduced for the first time in a host and results in the activation of T and B cells.
The response produces memory cells and plasma cells.
Plasma cells produce antibodies, while memory cells are long-lived and remain in the blood for a long time.
The duration from antigen entry to the appearance of the first antibody in the blood is called the lag phase, which is normally 4-7 days.
Secondary immune response occurs when the same antigen is injected into the host for the second time.
Memory cells directly get converted into plasma cells when activated by the antigen, resulting in a shorter lag phase (1-3 days) and 100 times more antibody production.
IgG is produced instead of IgM in secondary response, and the antibodies display a greater affinity for the antigen.

Adaptive Immune response – Humoral & Cellular

Humoral immunity is mediated by macromolecules like antibodies, complement proteins, and antimicrobial peptides located in extracellular fluids.
It contrasts with cell-mediated immunity and is associated with antibody production, cytokine production, germinal center formation, isotype switching, affinity maturation, and memory cell generation.
Its effector functions include pathogen and toxin neutralization, classical complement activation, and opsonin promotion of phagocytosis.

Cellular Immunity

Cellular immunity is an immune response that doesn't involve antibodies, instead relying on the activation of phagocytes, cytotoxic T-lymphocytes, and the release of various cytokines.
It protects the body through:
- T-cell mediated immunity: activating antigen-specific cytotoxic T cells that induce apoptosis in virus-infected cells or cancer cells.
- Macrophage and natural killer cell actions: destroying pathogens through recognition, cytotoxic granules, and phagocytosis.
- Cytokine secretion: influencing the function of other cells involved in immune responses.

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Description

Explore the pioneering studies of early vaccination that shaped the field of immunology. Learn about Louis Pasteur's contributions and the broader factors influencing infection prevention beyond vaccines. This quiz covers key concepts in immunology and historical developments in vaccination.