Innate Immunity Overview

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Questions and Answers

Which cells are derived from blood monocytes and differentiate into macrophages in target tissues?

Natural killer cells

T lymphocytes

B lymphocytes

Tissue macrophages (correct)

What distinguishes tissue macrophages from other immune cells in a blood count?

They are highly mobile in the bloodstream.

They are primarily involved in the adaptive immune response.

They originate from B cells.

They are not found in a full blood count. (correct)

What role do inflamed epithelial cells play in the immune response?

They produce antibodies.

They differentiate into macrophages.

They kill pathogens directly.

They secrete cytokines. (correct)

In which phase do monocytes develop into macrophages?

Once they reach target tissues Signup and view all the answers

What is the primary role of ferritin in the body?

Storage of iron Signup and view all the answers

Which of the following statements about macrophages is true?

They are capable of secreting cytokines. Signup and view all the answers

What is neutrophil chemotaxis primarily involved in?

Migrating to the site of infection Signup and view all the answers

During the process of phagocytosis, what do neutrophils primarily target?

Pathogens and debris Signup and view all the answers

In relation to iron storage, what is the function of ferritin?

Storing iron in a soluble form Signup and view all the answers

What occurs during the clean-up operation initiated by neutrophils at an infection site?

Phagocytosis of pathogens Signup and view all the answers

What percentage of white blood cells do neutrophils typically make up?

40-75% Signup and view all the answers

What primary function do neutrophils serve in the immune response?

Phagocytosing invading organisms Signup and view all the answers

Which type of immune cells specifically target multicellular parasites?

Eosinophils Signup and view all the answers

Which characteristic is true for neutrophils?

Have a segmented nucleus Signup and view all the answers

How many neutrophils are typically present in a full blood count (cmm)?

2000-7500 Signup and view all the answers

What are DAMPs primarily associated with?

Triggering inflammation in response to tissue damage Signup and view all the answers

Which receptors are involved in sensing DAMPs and PAMPs?

NOD-like receptors (NLRs) Signup and view all the answers

What initiates the signaling events that promote inflammation after DAMPs are recognized?

Cytosolic receptors Signup and view all the answers

What type of cells recognize necrotic cells as a form of DAMPs?

Phagocytes Signup and view all the answers

What type of response do DAMPs primarily promote in the immune system?

Inflammation Signup and view all the answers

What ions are responsible for the antimicrobial activity in household bleach?

Hypochlorous ions Signup and view all the answers

Which of the following is commonly known to contain hypochlorous ions?

Household bleach Signup and view all the answers

What is the primary function of hypochlorous ions in household bleach?

Antimicrobial activity Signup and view all the answers

Which of these substances does NOT contain hypochlorous ions?

Hydrogen peroxide Signup and view all the answers

Why are hypochlorous ions effective as an antimicrobial agent?

They react with proteins and nucleic acids Signup and view all the answers

What is the primary function of opsonization in the immune response?

To facilitate phagocytosis of microorganisms Signup and view all the answers

Which statement accurately describes the process of opsonization?

It involves the coating of microorganisms with serum proteins. Signup and view all the answers

What effect do serum proteins have on microorganisms during opsonization?

They enhance the attachment of microorganisms to phagocytes. Signup and view all the answers

Which of the following describes the outcome of effective opsonization?

The rate of phagocytosis of coated microorganisms increases. Signup and view all the answers

Which component is NOT directly involved in the process of opsonization?

B cells Signup and view all the answers

Study Notes

Innate Immunity Lecture Notes

Innate immunity is the first line of defense against infections
It is very fast, acting within 4 hours of infection
Innate immunity is less efficient than adaptive immunity
It doesn't have a memory response

Structure of the Immune System

The immune system is a mobile, circulating system
It contains fixed anatomical structures which are essential for its function

Primary Lymphoid Organs

The bone marrow and thymus gland are primary lymphoid organs
Bone Marrow: Forms immune cells during hematopoiesis
Thymus Gland: Site of lymphocyte maturation (education), B cells mature in bone marrow, T cells mature in the thymus

Secondary Lymphoid Organs

Lymph nodes and spleen
Lymph Nodes: Filter lymph, providing a site for antigen presentation to adaptive immune cells
Spleen: A massive lymph node, another site for antigen presentation to mature lymphocytes
Other organs including the liver also act as secondary organs

Cells of the Immune System (Innate)

Granulocytes: Family of white blood cells with granules in their cytoplasm
- Neutrophils: Most abundant WBCs (40-75%), first responders to infection, phagocytic, present antigens
- Eosinophils: 1-6% of WBCs, target multicellular parasites (worms), involved in allergic reactions
- Basophils: 0-1% of WBCs, involved in inflammation, parasitic infections, allergic reactions, bind IgE antibodies
Monocytes/Macrophages: Large cells involved in phagocytosis and antigen presentation
- Monocytes: Circulate in blood, become macrophages in tissues
- Tissue Macrophages: Derived from monocytes, phagocytic ,clear pathogens, cellular debris and dead/old cells
Lymphocytes (Agranulocytes): Small WBCs with large nuclei, no granules
- B cells: 10-15% of lymphocytes , responsible for antibody-mediated immunity, involved in humoral immunity, make antibodies, memory B cells
- T cells: 75% of lymphocytes (varies with immune response), express CD3 and T cell receptors (TCRs), recognize specific antigens
- Natural Killer (NK) cells: Larger, more primitive subtype, involved in both innate and adaptive immunity, destroy infected and cancerous cells.

Phagocytosis

Chemotaxis: The chemical attraction of phagocytes to microorganisms/damaged tissue.
Adherence: Attachment of phagocyte plasma membrane to the surface of the microorganism (uses PAMPs, such as Toll like receptors).
Ingestion: Phagocyte surrounds the microorganism with a phagosome
Digestion: Phagosome merges with lysosomes to form a phagolysosome, lysosomal enzymes digest the pathogen.

Opsonization

Coating a microorganism with molecules that are recognized by receptors on phagocytes helps them be more readily engulfed
Opsonins include components of the compliment system and antibody molecules

Pathways of Antigen Processing

Vesicular antigen processing pathway: Macrophage presents on MHC II for T helper cells
Cytosolic antigen processing pathway: viral antigen presented on MHC I for cytotoxic T cells

Inflammatory Response

The innate immune response localizes and contains infection. Inflammatory response occurs after infection.
Vasodilation and increased blood flow (erythema and warmth).
Increased vascular permeability (edema )
Release of inflammatory mediators (eg. bradykinins and prostaglandins) which cause pain.
Microvascular coagulation, preventing infection from spreading

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Description

This quiz covers the key concepts of innate immunity and its components within the immune system. Explore the primary and secondary lymphoid organs, their functions, and how they contribute to the body's first line of defense against infections. Test your knowledge on critical terms and concepts related to the innate immune response.