Immune System Quiz

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Questions and Answers

What is the primary characteristic of the innate immune system's kinetics?

Fast response (correct)

Moderately fast response

Delayed response

Very slow response

Which cells are primarily involved in the adaptive immune system?

Complement proteins

Monocytes and macrophages

Granulocytes and NK cells

B-cells and T-cells (correct)

Which of the following is NOT part of the innate immune system's humoral components?

Interferons

Lysozymes

Complement system

Ig molecules (correct)

What ability does the innate immune system possess in distinguishing pathogens?

Perfectly distinguishes self from non-self Signup and view all the answers

How do the effects of the innate immune system typically manifest?

Rare and lethally effective Signup and view all the answers

What type of immunity is present from birth and is genetically determined?

Innate Immunity Signup and view all the answers

What is the primary function of the immune system?

To protect against disease by identifying and killing pathogens Signup and view all the answers

Which of the following components is part of the innate immune system?

Monocytes Signup and view all the answers

What distinguishes adaptive immunity from innate immunity in terms of kinetics?

Adaptive immunity is generally slower to respond. Signup and view all the answers

Which components contribute to the innate immune response?

Barriers and nonspecific immune mechanisms Signup and view all the answers

In which compartment is the Adaptive Immune System primarily located?

Inside the body with specialized immune cells Signup and view all the answers

Which statement regarding adaptive immunity is accurate?

It develops during an organism's lifetime. Signup and view all the answers

Which of the following best describes the components of the innate immune system?

Consists of monocytes, macrophages, and NK cells. Signup and view all the answers

What is identified as a key distinction between the compartments for outside and inside the body?

The vast number of microbes in the outside environment Signup and view all the answers

What characterizes the immune response?

It involves an interplay between antigens and both immune systems Signup and view all the answers

What is the primary function of the innate immune system?

To contain infection until the adaptive immune response begins Signup and view all the answers

Which of the following cells are primarily involved in the adaptive immune response?

T-cells and B-cells Signup and view all the answers

Why did adaptive immunity develop according to the discussion on immune systems?

As a result of the innate immune system's limitations with highly mutable pathogens Signup and view all the answers

Which characteristic is NOT true of the innate immune system?

It is highly adaptable to various pathogens Signup and view all the answers

Which of these statements about the innate immune system is accurate?

It responds quickly but lacks adaptability Signup and view all the answers

Study Notes

Immune System

The immune system protects against disease by identifying and killing pathogens and tumor cells.
It detects a wide variety of agents, from viruses to parasitic worms.
The immune response is an interplay between antigens and innate and adaptive immune systems.

Protection from and Response to Microbial Invasion

Outside the body:
- Mechanical, chemical, and biological barriers prevent microbes from entering the body.
Within the body:
- The innate immune system provides the first line of defense against microbes.
- The adaptive immune system develops over time and provides specific immunity.
Cells:
- Cells involved in the immune response include monocytes/macrophages, granulocytes, NK cells, T-cells, B-cells, and APC (antigen-presenting cells).

Innate vs. Adaptive Immunity

Innate Immunity:
- Present at birth.
- Genetically determined.
- Provides a general defense against pathogens.
- Includes humoral and cellular components.
Adaptive Immunity:
- Develops during lifetime.
- Not genetically determined.
- Provides specific immunity against pathogens.
- Includes humoral and cellular components.

Innate Immune System and Adaptive Immune System

Innate Immune System:
- Components:
  - Monocytes/macrophages, granulocytes, NK cells
  - Complement system, opsonins, interferon, transferrin, lectins, anti-proteases, lysozymes, and antimicrobial peptides
  - Cytokines/chemokines
- Kinetics: Fast
Adaptive Immune System:
- Components:
  - T-cells, B-cells, and APC (antigen-presenting cells)
  - Ig molecule
  - Cytokines
- Kinetics: Slow

What is the Innate Immune Response?

Universal and evolutionarily conserved mechanism of host defense against infection.
Meditates the adaptive immune response in all multicellular organisms. It's adaptive only in vertebrates.
Possesses ancient receptors and effectors in their lineage.
Must provide protection against a wide variety of pathogens.
Distinguishes self from non-self perfectly.
Effects in innate immunity are rare and almost always lethal.

Adaptive Immune System

Components include T-cells, B-cells, APC, opsonins, Ig molecule, and cytokines.
It responds slowly to pathogens.

Pathogen Recognition and Inflammatory Signaling in Innate Immune Response

The innate immune system instructs the adaptive immune response to respond to microbial infections.
The decision to respond or not is determined by the genome-encoded receptors of the innate immune system.

How the Innate Immune System Distinguishes Between Self and Non-Self

The innate immune system recognizes repeating patterns of molecular structure on microbial surfaces.
These patterns are called Pathogen-Associated Molecular Patterns (PAMPs).
PAMPs are repeated structures and molecular patterns absent in humans but present in microbes.
Examples of PAMPs:
- LPS (lipopolysaccharide) - outer membrane of bacteria
- Lipoteichoic acid - gram-positive bacteria
- Flagellin - bacterial flagella
- dsRNA & ssRNA - double-stranded and single-stranded RNA

(PAMPs) Pathogen-associated molecular patterns

Repeated structures present in microbes.
Repeated molecular patterns.
Absent in humans, but present in microbes.
Examples:
- LPS...outer membrane of gram-negative bacteria.
- Lipoteichoic acid and peptidoglycan of gram-positive bacteria.
- Flagellin in bacterial flagella.
- dsRNA & ssRNA of viruses.

PRRs (Pattern Recognition Receptors)

PRRs are pattern recognition receptors that initiate an inflammatory response.
Infection of cells by microorganisms activates the inflammatory response.
The initial sensing of infection is mediated by innate pattern recognition receptors (PRRs).
PRRs recognize specific patterns of molecules associated with pathogens.
These molecules are often parts of bacterial cell walls (e.g., peptidoglycan).
PRRs can be found on the cell surface or within the cell (intracellular) like lysosomes.

Pattern Recognition Receptors (PRRs)

PRRs are receptors expressed on the plasma membrane of innate immunity cells (e.g., macrophages, neutrophils, dendritic cells).
They are also on various cellular compartments (e.g., lysosomes, endosomes, cytosol).
PRRs are able to detect extracellular and intracellular pathogens.
Each type of PRRs can recognize multiple pathogenic species that share a particular type of molecular pattern.

4 Key Families of Pattern Recognition Receptors (PRRs):

Toll-like receptors (TLRs): Transmembrane receptors
Rig-I-like receptors (RLRs): Cytoplasmic RNA helicases
Nod-like receptors (NLRs): Cytoplasmic sensors, located within the cell
C-type lectin receptors (CLRs): Transmembrane receptors

Recognition Mechanisms:

PAMPs (Pathogen-associated molecular patterns): Molecules released from pathogens.Recognized by PRRs.
DAMPs (Damage-associated molecular patterns): Molecules released from damaged or necrotic cells or tissues.Recognized by some NLRs, TLRs, and CLRs.
Lectin: a protein binds to carbohydrates. The role of lectins in recognition is less well understood.

Signaling pathways:

The intracellular signaling cascades triggered by PRRs lead to transcriptional activation of inflammatory mediators.
This coordinates the elimination of pathogens, and infected cells.
Aberrant activation can lead to immunodeficiency, septic shock, or induction of autoimmunity.

TLRs (Toll-like receptors):

The first type of TLR was identified as a gene product essential for the development of embryonic dorsoventral polarity in Drosophila.
It was later shown that TLRs play a critical role in the antifungal response of flies (Lemaitre et al., 1996).
To date, 12 members of the TLR family have been identified in mammals.
TLRs recognize bacteria and are significant to innate immunity.

Toll-Like Receptors (TLRs)

Toll-like receptors (TLRs) are a type of pattern recognition receptor (PRR) involved in the innate immune system's response to pathogens.
They are essential for recognizing pathogen-associated molecular patterns (PAMPs), which are molecules unique to pathogens.
TLRs are associated with defense against viral, bacterial, and fungal infections.
They initiate the immune response by recognizing specific PAMPs or pathogen-associated molecular patterns (PAMPs) expressed by pathogens.
TLRs are transmembrane proteins that have an extracellular domain that recognizes PAMPs and an intracellular domain that initiates signaling pathways.
The TLR signaling pathway activates various immune responses, such as the production of inflammatory cytokines, the activation of other immune cells (like B cells and T cells), and the enhancement of phagocytosis.

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Description

Test your knowledge on the immune system and its functions. This quiz covers topics such as innate and adaptive immunity, immune responses, and the various cells involved in defending the body against pathogens. Understand how the immune system protects you from diseases and microbial invasions.