Defensive Strategies - Adaptive Immune Response

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Questions and Answers

What initiates the adaptive immune response?

MHC molecules

Antigen presentation (correct)

Zoonosis

The presence of antibodies

What is the primary function of Antigen Presenting Cells (APCs)?

To generate herd immunity

To destroy pathogens directly

To produce antibodies

To present antigens to T cells (correct)

Which of the following statements best describes a characteristic of the adaptive immune response?

It is very specific and has memory. (correct)

It has a quick response but no memory.

It operates independently of antigens.

It is a non-specific response.

Where do T cells mature within the immune system?

Thymus gland Signup and view all the answers

What type of immunity arises from the presence of antibodies in the bloodstream?

Humoral immunity Signup and view all the answers

What does the term 'zoonosis' refer to in the context of the immune system?

The transmission of diseases from animals to humans Signup and view all the answers

Which statement correctly defines an antigen?

A molecule that stimulates the production of antibodies Signup and view all the answers

What type of cells does the lymphoid lineage primarily give rise to?

Lymphocytes and natural killer cells Signup and view all the answers

What distinguishes active immunity from passive immunity?

Active immunity generates immunologic memory, passive immunity does not. Signup and view all the answers

What type of anti-venom would neutralize the venom of several snake species?

Polyvalent anti-venom Signup and view all the answers

Who is credited with the first development of a vaccine?

Edward Jenner Signup and view all the answers

What is the purpose of a vaccine?

To expose the immune system to a microbial antigen for protection. Signup and view all the answers

What defines an epidemic?

A sudden rise in the prevalence of a disease within a population. Signup and view all the answers

What is the primary goal of herd immunity?

To protect individuals who are not immunized by slowing disease transmission. Signup and view all the answers

Which term describes a pandemic?

Epidemic that crosses international boundaries and affects a large area. Signup and view all the answers

What is the meaning of R0 in epidemiology?

The basic reproduction number indicating the average number of secondary infections produced by one infected individual. Signup and view all the answers

What is the primary function of antibodies?

To specifically bind with antigens. Signup and view all the answers

What are the components of an antibody?

Two heavy chains and two light chains. Signup and view all the answers

Which major histocompatibility complex (MHC) class is associated with the humoral response?

MHC II Signup and view all the answers

Which type of T cell is identified by the CD8+ marker?

Cytotoxic T cells. Signup and view all the answers

How are B cells primarily activated in the immune response?

Through interaction with antigens and helper T cells. Signup and view all the answers

What is the role of memory cells in the immune response?

To survive long-term and facilitate quicker response upon re-exposure to the same antigen. Signup and view all the answers

Which antibody type is primarily involved in the initial immune response against pathogens?

IgM Signup and view all the answers

What characteristic defines the hypervariable regions of an antibody?

They bind specifically to antigens. Signup and view all the answers

How does the Major Histocompatibility Complex (MHC) influence tissue graft acceptance?

By ensuring that the haplotypes match between donor and recipient. Signup and view all the answers

What is the primary distinction between MHC class I and class II?

MHC I interacts primarily with cytotoxic T cells, whereas MHC II interacts with helper T cells. Signup and view all the answers

What term describes the constant presence of a disease within a specified geographical area at low prevalence?

Endemic Signup and view all the answers

Compared to endemic diseases, what characterizes hyperendemic diseases?

They exhibit high prevalence in all age groups. Signup and view all the answers

What does R0 (R Zero) represent in epidemiology?

The reproductive rate of a pathogen in a fully susceptible population. Signup and view all the answers

Which of the following diseases has the highest mortality rate among infected cases?

Rabies Signup and view all the answers

Which disease is an example of a zoonosis?

Yellow fever Signup and view all the answers

What factor contributes to the emergence of novel pathogens?

Accidental importation or mutation producing new strains. Signup and view all the answers

How is lethality measured concerning infectious diseases?

By the percentage of infected cases that die. Signup and view all the answers

Which R0 value indicates a pathogen with a higher transmission rate?

R0 of 5 to 18 for measles Signup and view all the answers

Study Notes

Defensive Strategies -2: The Adaptive Immune Response

The adaptive immune response is highly specific and has memory, distinct from the innate response.
It is triggered by antigen presentation.
Antigen-presenting cells (APCs) play a crucial role in initiating the adaptive response.
Antigens, along with epitopes (the active part of the antigen), are involved.
Antibodies are produced as part of the response.
Major Histocompatibility Complex (MHC) class 1 and 2 molecules are essential components.
Vaccines stimulate immunity.
Herd immunity is a concept related to the collective protection of a population.
Novel pathogens and zoonotic diseases are important considerations.

Adaptive Immune Response -Cells

Lymphocytes (T and B cells) are derived from the lymphoid line (differentiated from myeloid line).
T cells mature in the thymus.
B cells mature in the bone marrow.
Helper T cells play a key role in organizing both cellular (cytotoxic T lymphocytes) and humoral responses (through B cells).

T Cells

T cells are derived from the thymus.
Two basic types are helper T cells (Th cells) and cytotoxic T cells (Tc cells).
Th cells are marked by CD4+.
Tc cells are marked by CD8+.
Helper T cells are critical coordinators of the adaptive immune response, though vulnerable to attack by HIV, the Human Immunodeficiency Virus.

B Cells

B cells originate in bone marrow and mature there.
They produce humoral responses, including plasma cells and memory cells.
Plasma cells, the effector cells, produce antibodies.
Memory cells provide a long-lasting response to repeated encounters with the same antigen.
Plasma cells have a short lifespan, undergoing apoptosis (programmed cell death).

Antigens and Epitopes

Antigens are molecules that react with preformed antibodies.
Most antigens are proteins, both intrinsic and extrinsic.
Epitopes are the portions of antigens that antibodies bind to.

Antibodies

Antibodies are soluble molecules produced in response to antigens.
Their key property is the ability to bind specifically to the antigen that prompted their production.
Antibody-antigen complexes are formed.
Antibodies are also known as immunoglobulins (Ig).
There are five antibody classes: IgG, IgM, IgA, IgD, and IgE. Each has a distinct role in immune responses.

MHC Molecules

MHC (Major Histocompatibility Complex) molecules are crucial for presenting antigens to T cells.
MHC class 1 molecules present intrinsic (internal) antigens.
MHC class 2 molecules present extrinsic (external) antigens.
MHC molecules are involved in tissue typing and graft acceptance.

Response to Pathogens

The body has responses (cellular and humoral) to intrinsic (intracellular) and extrinsic (extracellular) pathogens, activating different cell types.

Definitions

R₀ (pronounced R-naught) is the basic reproduction number.
It represents the average number of secondary infections caused by one infected individual in a wholly susceptible population. This number is indicative of a pathogen's transmissibility.
Vaccination efforts aim to reduce R₀ below 1.

Vaccine

Vaccine is a microbial antigen preparation (inactivated or weakened) to stimulate immunity.
Edward Jenner developed the first vaccine to protect against smallpox.
Several diseases have been significantly reduced due to vaccines (notably smallpox).

Herd Immunity

Herd immunity occurs when a substantial portion of the population is immune to a pathogen, protecting those individuals who cannot be vaccinated.
A high herd immunity level controls the spread of infectious disease.

Epidemics

Epidemics involve a sudden increase in the prevalence (incidence) of a disease.
Prevalence is the proportion of infected individuals in a group.
Severity can be measured by factors including mortality rates, R₀, and herd immunity levels.

Zoonoses

Zoonoses are diseases transferable from animals to humans.
Many emerging infectious diseases are zoonotic in origin.
Zoonotic transmission occurs through various methods.

Other Aspects of Immunity

Factors relating to vaccine technology, epidemiology, and transmission patterns are part of studying immunity.

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Description

Explore the complexities of the adaptive immune response in this quiz. Learn about antigen presentation, the role of APCs, and the function of T and B cells. Additionally, understand the significance of antibodies, MHC molecules, and concepts like herd immunity.