Innate Immunity Overview

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a systemic effect of proinflammatory cytokines?

Enhanced tissue perfusion

Fever from hypothalamic action (correct)

Reduced white blood cell production

Increased vascular permeability

What is a potential consequence of systemic TNF during inflammation?

Increased production of anti-inflammatory cytokines

Decreased cardiac function (correct)

Enhanced healing of tissue

Improvement in metabolic activity

What role does IL-8 play in acute inflammation?

Recruit neutrophils to the infection site (correct)

Increase production of antibodies

Promote tissue repair

Inhibit leukocyte migration

Which of the following describes a harmful effect of acute inflammation?

Leads to airway obstruction in acute epiglottitis Signup and view all the answers

What occurs when acute inflammation fails to resolve?

Development of chronic inflammation Signup and view all the answers

What is the primary role of the complement system upon activation?

To promote inflammation and enhance phagocytosis Signup and view all the answers

Which process describes the coating of a microorganism to make it more susceptible to phagocytosis?

Opsonization Signup and view all the answers

Which of the following is NOT a function of cytokines?

Producing antibodies directly Signup and view all the answers

What term describes cytokines that can act on various cell types?

Pleiotropic Signup and view all the answers

Which cytokine is NOT mentioned as an example in the context provided?

Interleukin 2 Signup and view all the answers

What is the nature of the signals generated by cytokines?

Can act autocrine, paracrine, or endocrine Signup and view all the answers

Which feature indicates that multiple cytokines can perform similar functions?

Redundant Signup and view all the answers

Which of the following best describes the complement proteins before activation?

Inactive and circulating in plasma Signup and view all the answers

Which cells perform extracellular killing in the innate immune response?

Natural killer (NK) cells Signup and view all the answers

What determines the activation of NK cells?

Balance of activating and inhibitory receptors Signup and view all the answers

What do NK cells release to induce cell death in the target cells?

Perforins and granzymes Signup and view all the answers

Which molecules do NK cells recognize to identify unhealthy cells?

Stress molecules on infected cells Signup and view all the answers

What role do Class I MHC molecules play in protecting healthy cells from NK cells?

They block signaling by activating receptors Signup and view all the answers

What can cause NK cells to activate and eliminate a target cell?

Altered self-molecules or lack of self-molecules Signup and view all the answers

What type of proteins do NK cells secrete to enhance the immune response?

Cytokines, such as interferon gamma Signup and view all the answers

Which of the following is NOT a component of innate immunity?

T cells Signup and view all the answers

Which of the following accurately describes the properties of cytokines?

Cytokines can act on different types of cells. Signup and view all the answers

What is the primary role of Type I Interferons in the antiviral immune response?

To inhibit viral replication. Signup and view all the answers

Which cytokines are known as pro-inflammatory and produced during the acute inflammatory response?

IL-1, IL-6, and TNF-α Signup and view all the answers

What triggers the liver to produce acute-phase proteins?

Cytokines released by activated immune cells. Signup and view all the answers

What is one of the major events in the inflammatory response?

Migration of white blood cells from capillaries to affected tissues. Signup and view all the answers

Which of the following can enhance phagocytosis and stimulate complement activation?

Acute-phase proteins like C-reactive protein and mannose binding proteins. Signup and view all the answers

What is the function of Type II Interferons?

To activate macrophages. Signup and view all the answers

What consequence does increased capillary permeability have during inflammation?

Allows for migration of white blood cells to affected tissues. Signup and view all the answers

Study Notes

Innate Immunity

Innate immunity is a non-specific defense mechanism that provides an immediate response to pathogens
Comprises mechanical and chemical barriers, phagocytic cells, circulating effector proteins, and inflammation

Mechanical and Chemical Barriers

Physical barriers such as skin and mucous membranes prevent pathogen entry
Chemical barriers include secretions like saliva, tears, and gastric acid, containing antimicrobial compounds
Normal bacterial flora competes with pathogens for nutrients and space, hindering their growth

Phagocytosis

Phagocytic cells like neutrophils, macrophages, and dendritic cells engulf and destroy pathogens
Steps of phagocytosis:
- Chemotaxis: Phagocytes are attracted to the site of infection
- Adherence: Phagocytes bind to pathogen surface
- Ingestion: Phagocyte engulfs the pathogen, forming a phagosome
- Digestion: Phagosome fuses with lysosomes, containing enzymes that break down the pathogen

Extracellular Killing

Natural killer (NK) cells eliminate large particles that cannot be phagocytosed, such as virus-infected cells and cancer cells
NK cells express surface markers CD16 and CD56 and perform extracellular killing as part of innate immunity
NK cell activation is determined by a balance between activating and inhibitory receptors
Activating receptors recognize stress molecules on infected or cancerous cells, while inhibitory receptors recognize self-MHC class I molecules on healthy cells

Circulating Effector Proteins

Complement System:
- A group of soluble plasma proteins circulating in an inactive form
- Activated by microbial surfaces or antibody-antigen complexes
- Effects:
  - Inflammation: Degranulation of mast cells and basophils leading to increased vascular permeability and phagocyte recruitment
  - Opsonization: Enhancing phagocytosis by coating pathogens with complement components
  - Direct lysis of bacteria
Cytokines:
- Small regulatory proteins that are produced in response to microbes and other antigens
- Facilitate communication between cells to trigger immune responses
- Involved in various aspects of innate and adaptive immunity, including inflammation and cell growth and differentiation
- Examples: Interleukin 1, IL-6, TNF-α, and interferons
- Act on target cells through autocrine, paracrine, and endocrine pathways
Acute Phase Proteins:
- Released by the liver in response to cytokines from activated immune cells
- Examples: C-reactive protein and mannose-binding proteins
- Enhance phagocytosis (opsonins) and stimulate complement activation

Inflammation

An innate immune reaction concentrating immune cells and products at the site of infection or tissue damage
Aims to eradicate infectious agents and promote tissue repair.
Major events:
- Vasodilation: Increases blood supply to the affected area
- Increased capillary permeability: Allows white blood cells to migrate to the tissues
- Migration of white blood cells: Leukocytes move from capillaries into the affected tissue
Pro-inflammatory cytokines such as IL-1, IL-6, and TNF-α are produced during inflammation
Systemic effects of these cytokines:
- Fever
- Production of acute phase proteins by the liver
- Leukocytosis (increased production of leukocytes)
Although essential, inflammation can have harmful effects, such as swelling and tissue damage. Chronic inflammation can lead to fibrosis, scarring, and loss of function.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the essential concepts of innate immunity, including its non-specific defense mechanisms against pathogens. Learn about mechanical and chemical barriers, as well as the process of phagocytosis performed by immune cells. This quiz will test your understanding of these fundamental immunological principles.