Introduction to Innate Immunity

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Questions and Answers

What is the primary purpose of the immune system?

To enhance physical endurance

To protect from infection (correct)

To facilitate digestion

To regulate blood pressure

Which of the following is NOT a function of the immune system?

Reproduce new cells (correct)

Maintain homeostasis

Wound healing

Clear dead cells

Which two main divisions comprise the immune system?

Innate and adaptive (correct)

Short-term and long-term

Inborn and acquired

Peripheral and central

Which year in the curriculum focuses on advanced topics in immunopathologies?

Year 2 Signup and view all the answers

What does innate immunity primarily deal with?

General environmental threats Signup and view all the answers

What is one recommended source for further information on immunology?

Essential Microbiology for Dentistry Signup and view all the answers

What concept will be revisited in Year 1 of the immunology curriculum?

Key concepts overview Signup and view all the answers

Which of the following processes is associated with innate immunity?

Immediate response to pathogens Signup and view all the answers

Which TLRs dimerize to recognize lipopolysaccharide (LPS)?

TLR1 and TLR2 Signup and view all the answers

What is commonly associated with MyD88-dependent TLR4 signaling?

Production of pro-inflammatory cytokines Signup and view all the answers

Which transcription factor is associated with MyD88-mediated signaling in TLR4?

NFκB Signup and view all the answers

What is a feature of MyD88-independent TLR4 signaling?

It utilizes MAP kinases Signup and view all the answers

Which of the following does NOT act as a ligand for TLR4?

Rhinovirus proteins Signup and view all the answers

What is the principal effect of TNF on muscle and fat tissues?

Catabolism leading to cachexia Signup and view all the answers

Which interleukin is primarily responsible for inhibiting IL-12 and class II MHC molecules?

IL-10 Signup and view all the answers

IL-12 plays a crucial role in which aspect of immune response?

Th1 differentiation Signup and view all the answers

Which pathways are activated by the binding of double stranded RNA to TLR3?

Type I interferon production Signup and view all the answers

What type of cells primarily produce IL-6?

Macrophages and endothelial cells Signup and view all the answers

Which chemokine receptor is associated with the recruitment of eosinophils and basophils?

CCR3 Signup and view all the answers

What cellular response is associated with the activation of N-formylmethionyl peptide receptors?

Neutrophil and macrophage activation Signup and view all the answers

Which TLR is specifically responsible for recognizing lipopolysaccharides from Gram-negative bacteria?

TLR4 Signup and view all the answers

What is the primary function of CXCL8 (IL-8)?

Neutrophil recruitment Signup and view all the answers

Which recognition system operates to detect microbial patterns when not present on mammalian cells?

Pattern recognition receptors (PRRs) Signup and view all the answers

Which receptor recognizes viral envelope proteins and dsRNA?

TLR3 Signup and view all the answers

What is one of the roles of macrophages in the immune system?

Phagocytosis Signup and view all the answers

Which molecules are known to activate complement in the immune response?

C-reactive proteins Signup and view all the answers

TLR2 is essential for recognizing which of the following types of substances?

Lipoproteins and lipopeptides Signup and view all the answers

Which toll-like receptor is specifically associated with recognizing modified lipopolysaccharides?

TLR4 Signup and view all the answers

What feature distinguishes innate immunity from adaptive immunity?

Rapid response Signup and view all the answers

What role do mast cells play in the immune response?

They release histamine which increases vascular permeability. Signup and view all the answers

Which of the following binds to the mannose receptor in the immune system?

Phosphorylcholine Signup and view all the answers

C-reactive protein is primarily involved in which mechanism of immune response?

Opsonization Signup and view all the answers

Which of the following accurately describes eosinophils?

They release inflammatory molecules and respond to parasites. Signup and view all the answers

Toll-like receptors are known to recognize which type of molecular patterns?

Conserved molecular patterns derived from potentially pathogenic sources Signup and view all the answers

Which sequence correctly describes the process of leukocyte extravasation?

Cytokine secretion, selectin rolling, increase in integrin affinity, transmigration. Signup and view all the answers

Which toll-like receptor can recognize both lipopeptides and lipoteichonic acid?

TLR2 Signup and view all the answers

What can occur if the inflammatory response is not well controlled?

It can damage the host’s tissues. Signup and view all the answers

What is the primary function of basophils in the immune system?

They participate in immediate hypersensitivity reactions. Signup and view all the answers

What is a major consequence of unregulated inflammation?

Pathological conditions affecting host tissues. Signup and view all the answers

Which component primarily assists in the rolling of leukocytes during extravasation?

Selectins Signup and view all the answers

In the context of mast cells, what does histamine primarily cause?

Increased smooth muscle contraction. Signup and view all the answers

What is one of the primary roles of cytokines in the inflammatory response?

To promote the rolling of leukocytes. Signup and view all the answers

What do serine proteases in the complement system assist with?

Activating the lectin pathway. Signup and view all the answers

Study Notes

Overview of Innate Immunity

Innate immunity is crucial for protection against infections and maintaining homeostasis.
It includes the clearance and recycling of dead cells, as well as processes involved in wound healing.

Structure of the Immune System

The immune system has two primary divisions: Innate and Adaptive.
Innate immunity is immediate and non-specific, while adaptive immunity develops over time and is highly specific.

Key Cells in Innate Immunity

Mast Cells: Release histamine, increasing vascular permeability, and are involved in allergic responses.
Basophils: Circulate in the blood and release histamine, playing a role in parasite defense.
Eosinophils: Release inflammatory molecules and are crucial in combating parasitic infections.

Inflammation

A protective mechanism characterized by leukocyte recruitment and plasma protein extravasation at infection sites.
Properly regulated inflammation is critical; dysregulation can cause tissue damage and pathology.

Extravasation Process

Involves several steps: cytokine secretion, leukocyte rolling mediated by selectins, integrin affinity increase, endothelial attachment, and finally, transmigration.

Circulating Effector Proteins

Complement Proteins: Play a role in opsonization and inflammation, enhancing the immune response.
Cytokines: Signaling molecules produced primarily by macrophages and T cells, mediating diverse biological effects:
- TNF: Activates endothelial cells, induces fever, promotes apoptosis.
- IL-1: Involved in inflammation and fever.
- Type I Interferons: Essential for antiviral defense and increased MHC expression.
- IL-6, IL-10, IL-15, IL-18, IL-23: Various roles in immune regulation and response.

Chemokines

Scouting proteins that guide leukocyte movement to sites of infection through specific receptors.
Examples include:
- CCL2 (MCP-1): Leucocyte recruitment.
- CXCL8 (IL-8): Neutrophil recruitment.

Features of Innate Immune Recognition

Recognizes pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs).
Key receptors include:
- Toll-like Receptors (TLRs): Detect various microbial components.
- C-type Lectin Receptors (CLRs), Nod-like Receptors (NLRs), RIG-I-like Receptors (RLRs): Different classes for recognizing specific pathogens.

Pattern Recognition Receptors (PRRs)

PRRs identify unique structures on pathogens (e.g., LPS from gram-negative bacteria).
Engagement leads to activation of innate immune responses, including cytokine production and phagocytosis.

Toll-like Receptors (TLRs)

Recognize conserved molecular patterns from pathogens, enhancing the specificity of immune responses.
TLRs activate signaling pathways leading to the production of pro-inflammatory cytokines and chemokines through MyD88 or MyD88-independent pathways.

Summary of Key Cytokines and Their Functions

TNF: Activation of inflammation; fever.
IL-1: Promotes inflammation and fever response.
IL-6: Stimulates acute-phase protein synthesis.
IL-10: Inhibits pro-inflammatory cytokine production.
IFN-α/β: Activates cells to defend against viral infections.

These elements form the foundation of innate immunity, playing a critical role in the body's first line of defense against infections and injury.

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Description

This quiz introduces the key concepts of innate immunity, providing foundational knowledge for Year 1 students. It consolidates important information from recommended readings, including 'Cellular and Molecular Immunology' and 'Essential Microbiology for Dentistry'. Test your understanding of the principles and components of innate immunity.