Innate and Adaptive Immunity

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

Which statement most accurately describes the traditional view of innate immunity?

  • A rapid, non-specific response to infection mediated by phagocytic cells, representing the first line of defense. (correct)
  • A slow, highly specific response to infection that improves with subsequent exposures.
  • A delayed, targeted response involving antibodies and T cells.
  • An immune response characterized by immunological memory and the generation of long-lasting immunity.

Which of the following bodily secretions and barriers are considered part of the first line of defense in innate immunity?

  • Saliva, stomach acid, and adaptive immune cells.
  • Skin, mucus linings, and natural killer cells.
  • Saliva, tears, and interferon.
  • Skin, saliva, tears, stomach acid, and mucus linings. (correct)

The immune system's response to 'perceived' danger involves only recognition mechanisms.

False (B)

In the context of molecular surveillance, what is the role of receptors?

<p>To recognize and bind to specific antigens, triggering an immune response. (C)</p> Signup and view all the answers

Adaptive immunity relies solely on germ-line encoded receptors for antigen recognition.

<p>False (B)</p> Signup and view all the answers

Which of the following statements best describes the initiation of host responses in innate immune sensing?

<p>Triggered by the recognition of pathogen-associated molecular patterns (PAMPs) through germ-line encoded pattern recognition receptors (PRRs). (A)</p> Signup and view all the answers

Which of the following is NOT true regarding innate immunity?

<p>Innate immunity is solely mediated by immune cells. (A)</p> Signup and view all the answers

What is one potential consequence of deficiency or polymorphisms in innate immunity?

<p>increased susceptibility to infections</p> Signup and view all the answers

Phagocytosis is a process exclusive to innate immunity.

<p>False (B)</p> Signup and view all the answers

Why is the idea that 'innate immunity = early' sometimes considered misleading?

<p>Because memory immune responses can also be fast. (B)</p> Signup and view all the answers

Which of these components is NOT a circulating plasma protein associated with innate immunity?

<p>Antibodies (IgG). (D)</p> Signup and view all the answers

Host responses initiated by recognition of pathogen (danger) associated molecular patterns by germ-line encoded ______________ receptors.

<p>pattern</p> Signup and view all the answers

Innate immunity elicits cell proliferation in response to a pathogen.

<p>False (B)</p> Signup and view all the answers

Which statement best reflects the current understanding of the specificity of innate immunity?

<p>Innate immunity uses relatively few receptors to provide coverage for a broad range of organisms. (D)</p> Signup and view all the answers

What is the significance of the 'danger signal' in the context of innate immunity and immunological tolerance?

<p>It is a signal that bridges innate and adaptive immunity, indicating the need for T cell activation. (C)</p> Signup and view all the answers

Dysregulation of the innate immune system, particularly related to the recognition of nucleic acids, underlies the pathogenesis of what syndrome?

<p>Aicardi-Goutieres syndrome</p> Signup and view all the answers

In the context of innate immunity, what is the significance of mechanisms like SamHD1, RNAseH2, and Trex1?

<p>They are enzymes that act to tightly regulate the system and prevent autoimmunity. (C)</p> Signup and view all the answers

What is the mechanism by which the Yaa mutation in BXSB mice bypasses the normal specificity of TLR7, leading to lupus-like autoimmunity?

<p>Yaa increases TLR-7 expression, resulting in a response to endogenous RNA. (A)</p> Signup and view all the answers

Innate immune activation leads to transcriptional responses. Which of the following responses is NOT directly associated?

<p>Antibody class switching. (C)</p> Signup and view all the answers

Describe what 'trained immunity' is.

<p>Functional reprogramming of innate immune cells</p> Signup and view all the answers

Defects in TLR3 has been linked to which disease?

<p>Herpes Simplex Encephalitis. (B)</p> Signup and view all the answers

Enhanced bacterial clearance and sepsis resistance is associated with with what deficiency?

<p>Caspase-12. (D)</p> Signup and view all the answers

Innate immunity can adapt.

<p>True (A)</p> Signup and view all the answers

Which of the following molecules is NOT part of the homeostatic mechanisms that dampen immune responses?

<p>Interferon gamma. (C)</p> Signup and view all the answers

Which of the following is NOT a mechanism of tissue injury in inflammation?

<p>Increase in IL-4. (D)</p> Signup and view all the answers

What statement best describes the effect of persistent stimulation on tissue damage and inflammation?

<p>Persistent stimulation can lead to chronic inflammation and tissue damage due to sustained immune activation. (B)</p> Signup and view all the answers

Failure of early microbial restriction during infection leads to:

<p>Persistent stimulation. (A)</p> Signup and view all the answers

What is the relationship between inflammation and infectious disease?

<p>Inflammation can contribute to infectious disease through failure of immune homeostasis. (D)</p> Signup and view all the answers

Which are true about innate immunity?

<p>Responses are triggered by germ-line encoded sensors. (C)</p> Signup and view all the answers

Coagulation factors are circulating ______________ proteins.

<p>plasma</p> Signup and view all the answers

Match the following examples with their respective defence:

<p>Saliva = Antibacterial Enzymes Mucus membrane = Traps Dirt Stomach Acid = Low pH Kills Tears = Antibacterial Enzymes</p> Signup and view all the answers

Which is the correct sequence of an immune system response to perceived danger?

<p>Recognition Mechanisms -&gt; Amplification &amp; Regulation -&gt; Effector Mechanisms (B)</p> Signup and view all the answers

Which of these answer options is not a potential cause of tissue injury?

<p>Langerhans Cells (D)</p> Signup and view all the answers

There needs to be cell proliferation for innate immunity to function.

<p>False (B)</p> Signup and view all the answers

Which of these options are NOT a type of cell in Autocrine & paracrine homeostasis?

<p>Foster Cells (B)</p> Signup and view all the answers

The molecular patterns recognized by the innate immune system are common to many pathogens and ____________

<p>self</p> Signup and view all the answers

Innate immunity cannot cause immunopathology

<p>False (B)</p> Signup and view all the answers

What is the role of the myeloid stem cells in the protective innate immunity?

<p>Epigenetic imprinting of macrophages (D)</p> Signup and view all the answers

Match the terms with their correct examples:

<p>sTNFR = IL1ra IL1 RII = Decoy receptors DAF = Decay accelerating factor plasma proteins = factor I H LBP protease inhibitors</p> Signup and view all the answers

Which of the following factors does cause a tissue injury in the system?

<p>Alkaline Phosphetase + (C)</p> Signup and view all the answers

Which statement accurately differentiates trained immunity from traditional adaptive immunity?

<p>Trained immunity depends on the rapid response of germ-line encoded sensors and is not restricted to immune cells, while adaptive immunity involves somatic cell rearrangement. (C)</p> Signup and view all the answers

The effectiveness of the innate immune system is limited to initiating responses without influencing the function of the adaptive immune system.

<p>False (B)</p> Signup and view all the answers

Describe how a deficiency in TLR3 might lead to increased susceptibility to Herpes Simplex Encephalitis.

<p>A TLR3 deficiency impairs the recognition of viral components, specifically double-stranded RNA, leading to a reduced or absent immune response against the herpes simplex virus in the brain.</p> Signup and view all the answers

Host responses are initiated by the recognition of pathogen (danger) associated ______ patterns by germ-line encoded pattern recognition receptors.

<p>molecular</p> Signup and view all the answers

Match each component of the innate immune system with its corresponding function.

<p>Complement (C1q) = Initiates the classical pathway of complement activation. Coagulation factors (Factor XII) = Triggers the intrinsic coagulation pathway. Pentraxins (CRP) = Binds to phosphocholine on microbes, activating complement. Membrane associated receptors (e.g., TLRs) = Recognize specific microbial components, initiating signaling cascades.</p> Signup and view all the answers

Which factor primarily determines the specificity of innate immune responses despite their seemingly non-specific nature?

<p>The limited number of receptors that recognize molecular patterns common to a broad range of organisms. (D)</p> Signup and view all the answers

Innate immunity's primary function is to halt proliferation.

<p>False (B)</p> Signup and view all the answers

Explain how increased levels of interferon may contribute to autoimmunity.

<p>Chronically elevated interferon levels can lead to the activation of autoreactive lymphocytes and the breakdown of self-tolerance, resulting in autoimmune disorders.</p> Signup and view all the answers

A hallmark of acute inflammation is the movement of leukocytes, particularly ______, from the blood into the affected tissue.

<p>neutrophils</p> Signup and view all the answers

Which mechanism does the body employ to maintain homeostasis during inflammation?

<p>Cytokine antagonists which help to modulate the immune response. (D)</p> Signup and view all the answers

Describe the activation of the NALP3 inflammasome.

<p>The NALP3 inflammasome is activated by various danger signals that lead to the recruitment of Caspase 1, resulting in the cleavage of pro-cytokines such as IL-1β.</p> Signup and view all the answers

Flashcards

Innate Immunity

Rapid, non-specific response to infection, acting as the first line of defense, mediated by phagocytic cells

First lines of defense

Physical, chemical, and biological barriers that prevent pathogens from entering the body, like skin, saliva, and gut bacteria.

Immune system function

The immune system's response to perceived danger, involving recognition, amplification/regulation, and effector mechanisms.

Innate immune sensing

Host responses initiated by recognizing pathogen-associated molecular patterns (PAMPs) through germ-line encoded receptors.

Signup and view all the flashcards

Innate immune sensing

Host responses initiated by recognition of pathogen (danger) associated molecular patterns by germ-line encoded pattern recognition receptors

Signup and view all the flashcards

Adaptive immunity

The ability of the immune system to recognize and respond to an antigen with high specificity.

Signup and view all the flashcards

Innate immunity sensing

Host responses initiated by recognition of pathogen (danger) associated molecular patterns by germ-line encoded pattern recognition receptors

Signup and view all the flashcards

Innate immunity: Plasma portion

Circulating plasma proteins like complement (C1q), coagulation factors, and pentraxins (ex: CRP).

Signup and view all the flashcards

Innate immunity: Cellular portion

Membrane-associated receptors (Toll-like receptors) and cytosolic receptors (detecting nucleic acids) in the cytoplasm.

Signup and view all the flashcards

Opsonization

The process where pathogens are coated with proteins and targeted for destruction.

Signup and view all the flashcards

Innate immunity vs Autoimmunity

Innate immunity recognizes molecular patterns common to pathogens, but also to “self,” which can cause autoimmunity.

Signup and view all the flashcards

Recognition of non-self

T cell activation requires an accessory cell presenting antigen.

Signup and view all the flashcards

Immune Regulation

Immune response must be tightly regulated to prevent autoimmunity.

Signup and view all the flashcards

TLR7

In BXSB (Yaa) Mice TLR7 expression is increased in this way increasing likelihood of response to endogenous RNA.

Signup and view all the flashcards

Immune Response at Transcription Level

After innate immune activation, responses occur at the transcriptional level.

Signup and view all the flashcards

Acute inflammation

The acute innate response

Signup and view all the flashcards

Endocrine amplification

Activation of systemic and local immune system

Signup and view all the flashcards

Can you adapt?

Innate immunity can adapt, but not as specifically

Signup and view all the flashcards

Factors that regulate

IL10, changes in mRNA, down regulation of signaling

Signup and view all the flashcards

Inflammation

The symptoms of inflammation

Signup and view all the flashcards

Pathway of disease

Failure of immune responses to limit infection

Signup and view all the flashcards

Responses triggered

Cell-associated and cell-free plasma proteins

Signup and view all the flashcards

Autoimmunity

Important but cause autoimmunity if not regulated

Signup and view all the flashcards

Study Notes

  • Innate immunity is a swift, non-specific response to infection, acting as the body's first line of defense
  • Phagocytic cells like neutrophils and macrophages mediate innate immunity

First Lines of Defense

  • Saliva contains antibacterial enzymes
  • Tears also contain antibacterial enzymes
  • Skin prevents entry of harmful substances
  • Mucus linings trap dirt and microbes
  • Stomach acid's low pH kills harmful microbes
  • "Good" gut bacteria compete with harmful bacteria

Immune System

  • The immune system responds to “perceived” danger
  • This involves recognition mechanisms, amplification and regulation, and effector mechanisms, leading to killing and healing

Molecular Surveillance

  • Molecular surveillance relies on receptors

Adaptive Immunity

  • Adaptive immunity involves B and T cells
  • Adaptive immunity uses Ig and TCR gene re-arrangement
  • Somatic cells in adaptive immunity is not equal to next generation

Innate Immune Sensing

  • Host responses start with the recognition of pathogen-associated molecular patterns through germ-line encoded pattern recognition receptors
  • This sensing happens in cell-associated and cell-free environments
  • Sensing is not restricted to immune cells
  • Factor XII, CRP, and C1q/MBL are involved in innate immune sensing

Deficiency or Polymorphisms in Innate Immunity

  • A Mal functional variant is associated with protection against some diseases
  • TLR4 mutations are associated with endotoxin hyporesponsiveness in humans
  • TLR3 deficiency is found in patients with Herpes Simplex Encephalitis
  • A polymorphism in human TLR2 is associated with increased susceptibility to tuberculous meningitis
  • Human TLR1 deficiency is associated with impaired Mycobacterial Signaling and Protection from Leprosy Reversal Reaction
  • Polymorphism of the human Toll-like receptor 2 gene in tuberculosis disease
  • Enhanced bacterial clearance and sepsis resistance occur in caspase-12-deficient mice
  • Autoreactive B Cell Responses to RNA-Related Antigens can occur, caused by TLR7 Gene Duplication
  • Herpes Simplex Virus Encephalitis can occur in Human UNC-93B Deficiency
  • Pyogenic Bacterial Infections can occur in Humans with MyD88 Deficiency

Phagocytes and Innate Immunity

  • Neutrophils and macrophages are phagocytes

Innate Immunity and Evolution

  • Innate immunity and phagocytosis are primitive

Phagocytosis

  • Phagocytosis is not equal to innate immunity

Innate Immunity Timing

  • Innate immunity occurs early in the immune response
  • Memory immune responses can also be fast

Innate Immunity Components

  • Includes circulating plasma proteins like Complement (C1q), Coagulation factors (Factor XII), and Pentraxins (CRP)
  • Includes immune cells and all cells
  • Immune cells use Membrane associated receptors like Toll-like receptors
  • All cells use Cytosolic receptors
  • Cytosolic receptors target Nucleic acids in the cytoplasm

Innate Immunity and Cell Proliferation

  • Innate immunity doesn't equal cell proliferation

Innate Immunity Specificity

  • Innate immunity is non-specific
  • Only a few receptors provide coverage for a broad range of organisms

Innate Immunity and Recognition

  • Innate immunity recognizes non-self
  • T cell activation requires an accessory cell to present antigens
  • Antigen presentation and T cell receptor recognition do not equal a response
  • The "danger hypothesis" is relevant for immunological tolerance
  • Innate immunity is a danger signal exclusively for non-self

Aicardi-Goutieres Syndrome

  • No other information relating to this condition is shared

Innate Immune System Regulation

  • Must be tightly regulated to avoid autoimmunity

Specificity of Innate Immunity

  • Not so specific
  • Viral SS RNA and TLR7 are also relevant
  • Intracellular endosomal localisation
  • GU rich and unmethylated
  • A high viral RNA concentration in endosomes
  • Yaa overcomes specificity by increasing TLR-7 expression, causing a response to endogenous RNA

Transcriptional Responses of Innate Immunity

  • It can cause transcriptional responses, interferon response, cell cycle regulation, cytokines, chemokines etc

Non-Specific Innate Immune Responses

  • Not non-specific

Pathogen-Specific Responses

  • Pathogen specific responses are generated through TLR, TIRAP, MyD88, IRAK4, IRAK2, TRAF6, MAPK/AP1, NFkB etc

Post-Transcriptional Innate Immune Responses

  • Includes pro-cytokines like IL1 and IL18
  • Includes NLRs such as NOD1/2 and NALPs
  • Activation of IL1 is mediated by Alum involving NALP3 and Caspase1

Innate Immune Responses

  • When present in the bigger picture
  • Recruits host defences
  • Augments adaptive immune response

Pathway To Infectious Disease

  • Involves:
  • Failure of early microbial restriction
  • Persistent stimulation
  • Failure of immune homeostasis
  • Disease

Endocrine Amplification

  • Happens during the acute phase response
  • Complement
  • Coagulation
  • Fibrinolysis
  • Pentraxins
  • CRP
  • SAP
  • Transport Proteins
  • Proteinases
  • Proteinase inhibitors
  • Albumin
  • Causes:
  • Fever
  • Gluconeogenesis
  • Proteolysis

Innate Immunity Adaptation

  • Can adapt (or remember)?

Homeostasis in Innate Immunity

  • Includes Autocrine & paracrine actions
  • Can use IL10
  • Foster 2007 (Nature), Kim 2007 (Nature Medicine), O’Neill 2011 (Nature Rev Immunol) etc are relevant
  • T regs (IL10 & TGFb) are relevant

Homeostasis

  • Apoptosis
  • Cytokines
  • Cytokine antagonists
  • Decoy receptors
  • Cell associated inhibitors
  • Plasma proteins

Trained Immunity Article

  • Infection or vaccination may impact innate immune cells
  • Epigenetic reprogramming is involved to train innate immune cells
  • Includes Histone modification, DNA methylation and Modulation of miRNA Includes:
  • Adaptive states
  • Mucosal tolerance
  • Limitation of tissue damage in infection
  • Innate immunity maturation
  • Nonspecific protection by vaccines
  • Hyperinflammation in tissues
  • Atherosclerosis

Tuberculosis Article

  • BCG vaccination educates Hematopoietic Stem Cells
  • Myeloid stem cells do this by imprinting epigenetically
  • They use 'pro-inflammatory’ macrophages
  • Which increased Mtb killing

Inflammation

Tissue Injury In Inflammation

  • Through cellular toxins such as Neutrophils, CD8 Cytotoxic T cells, Eosinophils
  • Through tissue hypoxia
  • Vasodilatation & cardiogenic shock
  • Intravascular coagulation
  • Mitochondrial dysfunction
  • Chronic inflammation
  • Persistent stimulus
  • Homeostatic failure

Summarised Key Points

  • Responses are triggered by germ-line encoded sensors
  • Cell-associated & Cell-free plasma proteins
  • Important for health
  • Evolutionarily conserved
  • So is phagocytosis, but that doesn’t mean phagocytosis equals innate immunity
  • Has recognisition for molecular patterns
  • Common to many pathogens…and to “self”
  • Can cause autoimmunity
  • Adapts to past experience
  • Has trained immunity
  • Augments adaptive immunity
  • Role as an adjuvant in vaccination
  • Causes Inflammation turning into disease
  • Including Failure of immune homeostasis
  • Requires to not have cell proliferation
  • Is fast

Studying That Suits You

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

Quiz Team

Related Documents

More Like This

Use Quizgecko on...
Open
Browser
Browser