MICROBIO 1.3

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Questions and Answers

What type of bacteria can most likely avoid being killed via the complement pathway due to the presence of LPS?

Cocci bacteria

Acid-Fast bacteria

Gram Positive bacteria

Gram Negative bacteria (correct)

Which process enhances the attraction of phagocytic cells and lymphocytes to the site of infection?

Activation of the clotting cascade

Cytokine inhibition

Chemotaxis (correct)

Antigen presentation

Which of the following is NOT a characteristic of inflammation?

Redness (Rubor)

Reduction of blood flow (correct)

Swelling (Tumor)

Heat (Calor)

What is indicated by increased production of antimicrobial peptides upon recognizing an antigen?

Enhanced killing of microorganisms Signup and view all the answers

Which immune response is characterized by increased production of defense proteins and pro-inflammatory mediators?

Acute phase response Signup and view all the answers

What does the term 'functio laesa' refer to in the context of inflammation?

Loss of function Signup and view all the answers

Which type of immune cell is primarily responsible for production of cytokines during inflammation?

Pro-inflammatory cells Signup and view all the answers

During inflammation, which of the following phenomena is primarily responsible for increased vascular permeability?

Vasodilation Signup and view all the answers

The primary function of the complement system in the immune response includes enhancing which of the following?

Phagocytosis/opsonization Signup and view all the answers

What is the primary function of innate immunity?

To recognize and eliminate or tolerate microbes quickly Signup and view all the answers

Which of the following is NOT a component of the innate immune system?

T lymphocytes Signup and view all the answers

What is the role of pattern recognition receptors (PRRs) in the innate immune response?

To recognize structures present in microbes Signup and view all the answers

Which component of the innate immune system enhances phagocytosis and promotes inflammation?

Complement system Signup and view all the answers

What initiates the adaptive immune response based on the information provided?

Phagocytes processing antigens Signup and view all the answers

Which type of immune cells are known to induce inflammation within the innate immune system?

Macrophages Signup and view all the answers

What is the final product of all three complement pathways?

Membrane Attack Complex (MAC) Signup and view all the answers

What role does the adaptive immune system play when the innate immune system fails?

It provides immunological memory. Signup and view all the answers

Which process is NOT a function of antibodies in the humoral immune response?

Producing cytokines. Signup and view all the answers

What distinguishes CD8 'Cytotoxic' T cells from CD4 'Helper' T cells?

CD8 T cells kill virus-infected and damaged cells. Signup and view all the answers

What is the fate of T cells that wrongly identify 'self' during development?

They are eliminated. Signup and view all the answers

How do B cells respond when activated by an antigen?

They synthesize immunoglobulins. Signup and view all the answers

What is the role of T regulatory (Tregs) cells in the immune system?

They suppress and regulate immune responses. Signup and view all the answers

What does the term 'immunoglobulin' refer to?

Glycoprotein molecules produced by plasma cells. Signup and view all the answers

Which step is crucial for the activation of T cells?

Presentation of antigens. Signup and view all the answers

What does a successful activation of Helper (CD4) T cells lead to?

Secretion of antibodies by B cells. Signup and view all the answers

Study Notes

Host-Pathogen Interactions Pt. I

The first part of the course is an introduction to the immune system.
The previous class covered microbiota and disease establishment.
The current class focusses on how the body fights infections by describing the immune system.

Immunity

Innate immunity and adaptive immunity are the two components of the immune system.
Innate immunity involves physical barriers, chemical barriers, and cellular defenses.
Adaptive immunity features active and passive immunity acquired through natural means, vaccination, maternal transfer, or artificial means.

Class Objectives

Differentiate between innate and adaptive immunity.
Describe the components and functions of the innate immune system.
Identify immune cells based on their roles and pictures.
Explain how the innate system activates the adaptive system.
Understand the different types of lymphocytes and their activation/roles.
Define antibodies and immunological memory.
Differentiate between MHC class I and MHC class II.

Big Picture

Antigens are foreign substances triggering an immune reaction.
Exposure to antigens results in an immune response or tolerance.
Innate and adaptive immunity work together in response to pathogens.

Innate vs. Adaptive Immunity

Innate immunity is rapid but non-specific.
Adaptive immunity is slower but highly specific.
Innate immune response to a first exposure is more significant than a second.
Adaptive immune response to a second exposure is much more significant than a first.

Cells of Innate & Adaptive Immune System

Innate and adaptive immune cells share a common origin.
Innate immune cells include myeloid stem cells, such as neutrophils, macrophages, basophils, eosinophils, monocytes among others.
Adaptive immune cells include lymphoid stem cells, such as lymphocytes, B-cells, T-cells.

Innate Immune System

Early, generalized first-line defense.
Recognizes microbes via Pattern Recognition Receptors (PRRs) that bind to Pathogen-Associated Molecular Patterns (PAMPs).
Involved in general responses to pathogens.
Includes phagocytes, dendritic cells, natural killer cells, and pro-inflammatory cells.

Components of the Innate Immune System: Cellular

Skin, mucous membranes, and mechanical defenses (coughing, sneezing).
Phagocytic cells (neutrophils, macrophages).
Pro-inflammatory cells (macrophages, mast cells, eosinophils, basophils).
Antigen-Presenting Cells (APCs) initiate adaptive responses.
Natural Killer (NK) cells kill infected cells.
Neutrophil extracellular traps (NETs).

Components of the Innate Immune System: Humoral

Body fluids like bile, acids, tears, mucous- these use antimicrobial peptides to fight pathogens.
Complement system enhances phagocytosis and induces inflammation.
Cytokines- proteins released by cells signaling for reactions (pro-inflammatory & anti-inflammatory).
Chemokines- cytokines that attract leukocytes (inflammatory response).

Complement - "Complements Antibodies"

Complement system makes invading micro-organisms more susceptible via phagocytosis (opsonization) or lysis
Promotes inflammatory response
The complement pathway produces substances that attract white blood cells
Complement triggers either classical (antigen-antibody complexes), alternative (bacterial LPS), or lectin (mannose sugars) pathways.
Can result in the formation of the membrane attack complex (MAC) that causes bacterial lysis.
LPS (lipopolysaccharide) can block MAC, preventing Gram-negative bacteria from being killed.

Consequences of Recognizing Antigen

Increased antimicrobial peptide production
Secretion of inflammatory mediators.
Activation of complement
Activation of clotting cascade
Chemotactic attraction of cells.
Acute phase response.
Inflammation.

Inflammation

Characterized by redness, heat, swelling, and pain (rubor, calor, tumor, dolor).
Leads to a loss of function.

Adaptive Immune Response

Lymphocytes

CD8 cytotoxic T cells kill infected/damaged cells.
CD4 helper T cells assist cytotoxic T and B cells.
B cells produce antibodies

Lymphocyte Development, Activation, & Antigen Presentation

T and B cells go through development to recognize self from non-self.
Activated T cells divide and proliferate.
Helper T cells secrete cytokines to activate other cells.
Cytotoxic T cells kill cells bearing antigens.
B cells differentiate into plasma cells secreting antibodies.

Immunoglobulins (Antibodies)

Immunoglobulins (IgA, IgD, IgE, IgG, IgM) are glycoprotein molecules secreted by plasma cells.
They have various structural and functional roles, affecting pathogens by agglutination, neutralization, opsonization, complement activation.

Initiation of Adaptive Immune Responses

Microbial antigens trigger dendritic cells to take up and process antigens and present on MHC class II molecules.
They activate helper T cells through MHC class II antigen presentation.
Activated helper T cells activate B cells to produce antibodies.

Major Histocompatibility Complex (MHC)

Glycoproteins present antigens for T cell activation.
MHC class I presents endogenous antigens on all nucleated cells to cytotoxic T cells.
MHC class II presents exogenous antigens on antigen-presenting cells to helper T cells.

Immunological Memory

Provides immunity through faster, stronger responses to repeat exposures.
Subsequent encounters with the pathogen result in a rapid and enhanced response.

Test Your Knowledge (Various)

Various questions about the immune system and immune cells from previous lectures/slides.

Also A Scientist

Brigitte Askonas: A scientist who played a significant role in immunology.
Askonas research on B cells and macrophages.

Studying That Suits You

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

Description

This quiz focuses on the introduction to the immune system, detailing both innate and adaptive immunity. You will explore the components, functions, and roles of immune cells and how they interact in the body's defense against infections. Test your understanding of key concepts such as antibodies and immunological memory.