Immunology Quiz on Autoimmune Diseases
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Questions and Answers

Which treatment method is specifically aimed at reducing autoantibody levels?

  • Plasmapheresis (correct)
  • Antibody Therapy
  • Steroids
  • Biologic Agents

Which cytokine is crucial for the activation of cytotoxic T-lymphocytes?

  • IL-10
  • IL-2 (correct)
  • TNF-β
  • IL-4

Class II MHC molecules are primarily expressed on which type of cells?

  • APCs (correct)
  • CD8+ T Cells
  • Endothelial Cells
  • Red Blood Cells

Which mechanism is primarily used by cytotoxic T cells to destroy infected cells?

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

Which type of cells produce interferons in response to viral infections?

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

What immunoglobulin is present in the blood of newborns?

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

What is the primary function of the Fc-fragment of an antibody?

<p>Participate in activation of cells of innate immunity (A)</p> Signup and view all the answers

Which cytokine is essential for promoting interferon-gamma production?

<p>Interleukin 12 (D)</p> Signup and view all the answers

Which pair of immunoglobulins is recognized for its antitumor activity?

<p>IgG, IgM (D)</p> Signup and view all the answers

What causes tumor development even in the presence of an immune response?

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

Which molecule is known to function as a complement inhibitor?

<p>DAF (Decay Acceleration Factor) (C)</p> Signup and view all the answers

Which characteristic is true regarding induced tolerance?

<p>It is formed later in life (D)</p> Signup and view all the answers

What process ensures the transfer of immunoglobulins from blood to mucous membrane secretions?

<p>Transcytosis (C)</p> Signup and view all the answers

Which type of cells play a significant role in phagocytosis in the human body?

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

What is the primary function of Th1 cells in the immune response?

<p>Cell-mediated Immunity (D)</p> Signup and view all the answers

Identifying what type of immune defense is performed by the adaptive immune system is key. Which is true?

<p>Adaptive Immune System (A)</p> Signup and view all the answers

What mechanism allows non-specific defense factors to act without prior exposure?

<p>Contact with Antigen without Prior Contact (D)</p> Signup and view all the answers

Which is not a humoral factor of non-specific defense?

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

Which cells are preferentially activated by Toll-like receptors (TLRs)?

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

What process primarily occurs within the thymus to ensure tolerance to intrinsic antigens?

<p>Negative Selection (D)</p> Signup and view all the answers

The differentiation and counting of leukocyte types is typically performed with what technique?

<p>Light Microscopy (C)</p> Signup and view all the answers

What is the main function of NK cells?

<p>Destroy target cells without phagocytosis (C)</p> Signup and view all the answers

Which molecules are necessary for the activation of naive CD4+ T-lymphocytes?

<p>MHC Class II, CD80 (C)</p> Signup and view all the answers

What receptor is primarily involved in the activation of B lymphocytes?

<p>BCR (C)</p> Signup and view all the answers

What type of cells are responsible for antibody production in the humoral immune response?

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

Which protein initiates the classical pathway of the complement system?

<p>C1 (A)</p> Signup and view all the answers

What is the primary role of regulatory T cells (Treg)?

<p>Suppress Immune Response (A)</p> Signup and view all the answers

What does the CD4 molecule primarily bind to?

<p>MHC Class II (C)</p> Signup and view all the answers

Which immunoglobulin predominates in upper respiratory tract secretions?

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

What structure is needed for a T cell to interact with an antigen-presenting cell?

<p>Immunological Synapse (C)</p> Signup and view all the answers

Cytotoxic T cells primarily recognize infected cells through which mechanism?

<p>Interaction with MHC Class I (D)</p> Signup and view all the answers

Which surface markers are used to identify T-lymphocytes?

<p>CD3 and CD19 (C)</p> Signup and view all the answers

What reflects the functional status of the humoral immune system?

<p>Serum immunoglobulin levels (C)</p> Signup and view all the answers

What is the primary function of type I interferons in immune responses?

<p>Anti-viral Immunity (A)</p> Signup and view all the answers

When are NK cells activated?

<p>In absence of MHC Class I molecules (B)</p> Signup and view all the answers

Which method involves the use of labelled antigens to detect specific substances?

<p>ELISA (C)</p> Signup and view all the answers

CD19 is a crucial marker for identifying which type of immune cells?

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

How is the antigen or antibody typically labelled in an ELISA assay?

<p>Enzymatically (C)</p> Signup and view all the answers

What is the role of Th2 cells in the immune response?

<p>Activate humoral immunity (C)</p> Signup and view all the answers

What is the purpose of the EAC-rosette formation reaction?

<p>Determine the absolute number of lymphocytes (A)</p> Signup and view all the answers

What is the main function of Toll-like receptors (TLRs) in the immune system?

<p>Recognize PAMPS (Pathogen-Associated Molecular Patterns) (C)</p> Signup and view all the answers

Which immunoglobulin is primarily involved in immediate-type hypersensitivity reactions?

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

Which type of immune response involves T lymphocytes?

<p>Delayed-type hypersensitivity (D)</p> Signup and view all the answers

What indicates the clinical manifestation of hypersensitivity?

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

Which characterizes anaphylaxis?

<p>Rapidly developing life-threatening allergic reaction (D)</p> Signup and view all the answers

What cells participate primarily in the DHT reaction?

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

Hemolytic disease of the newborn typically results from which condition?

<p>Rh incompatibility (D)</p> Signup and view all the answers

Which interleukin is crucial for eosinophil activation during allergic reactions?

<p>IL-5 (A)</p> Signup and view all the answers

What process ensures the specific diversity of antibodies?

<p>Recombination of gene segments (B)</p> Signup and view all the answers

Which technique is used to produce monoclonal antibodies?

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

Cytotoxic effects of T-Killer cells are primarily due to which mechanism?

<p>Enzyme perforation (D)</p> Signup and view all the answers

Flashcards

Plasmapheresis: How does it work?

A procedure that removes autoantibodies from the blood to treat autoimmune diseases.

What role does IL-2 play in immunity?

A cytokine that is essential for the activation and proliferation of cytotoxic T-lymphocytes.

Where are Class II MHC molecules found?

Antigen-presenting cells (APCs) express MHC class II molecules on their surface.

How do cytotoxic T cells destroy target cells?

Cytotoxic T cells induce apoptosis in infected or abnormal cells by triggering programmed cell death.

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What cells produce interferons?

Leukocytes, particularly dendritic cells, produce interferons.

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Which antibody is important for newborn immunity?

IgG is the only immunoglobulin that can cross the placenta, providing passive immunity to the fetus.

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What does the Fc fragment of an antibody do?

The Fc fragment on an antibody binds to receptors on immune cells, activating them.

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What is the main function of the Fc fragment of an antibody?

The Fc fragment of an antibody helps to activate cells of the innate immune system, such as macrophages and neutrophils.

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How do NK cells kill?

NK cells directly destroy target cells without engulfing them. They induce apoptosis, a programmed cell death, in the target cell.

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What activates naive CD4+ T cells?

MHC Class II molecules on antigen-presenting cells, along with co-stimulatory signals from CD80, are crucial for activating naive CD4+ T lymphocytes.

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What activates B lymphocytes for a T-dependent antigen?

B-cell receptor (BCR) is the surface receptor on B lymphocytes that binds to antigens, triggering the activation of these cells.

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Which cells produce antibodies?

Plasma cells are differentiated B cells that specialize in secreting antibodies, the main weapon of the humoral immune response.

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What protein starts the classical complement pathway?

The classical pathway of the complement system is triggered by the C1 complex binding to immune complexes, like antibodies bound to antigens.

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What is the primary function of Treg?

Regulatory T cells (Treg) act as immune suppressors, preventing excessive immune responses and maintaining tolerance to self-antigens.

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What does CD4 bind to?

CD4, a molecule found on helper T cells, interacts with MHC Class II molecules on antigen-presenting cells to initiate an immune response.

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Which immunoglobulin is abundant in the respiratory tract?

IgA is the primary immunoglobulin found in mucosal secretions, like those in the respiratory tract, providing protection against pathogens entering these areas.

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What structure allows T cell and antigen-presenting cell interaction?

The immunological synapse is the specialized contact point between a T cell and an antigen-presenting cell, where antigen recognition and signaling take place.

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How do T-killers recognize their target cells?

Cytotoxic T cells (T-killers) recognize infected cells through MHC Class I molecules, usually during viral infections, and eliminate them.

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What is the function of Type I interferons?

Type I interferons (alpha and beta) are crucial for establishing anti-viral immunity, activating immune cells, and suppressing viral replication.

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How are NK cells activated?

NK cells get activated when they detect the absence of MHC Class I molecules on a cell, often found in infected or cancerous cells.

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Which cells express CD19?

CD19 is a surface marker specifically found on B cells, making it a valuable tool for identifying and isolating these cells.

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What is the role of Th2 cells in the immune response?

Th2 cells are crucial for activating the immune response, especially in humoral immunity, where they promote antibody production.

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What do TLRs recognize?

TLRs, or Toll-like receptors, are crucial for recognizing pathogen-associated molecular patterns (PAMPs), triggering the innate immune response against pathogens.

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CD3 and CD19

Surface receptors used to identify T-lymphocytes and B-lymphocytes.

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Serum Immunoglobulin Levels

The functional activity of the humoral immune system, which involves production and circulation of antibodies.

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ELISA

A technique that uses labelled antibodies or antigens to detect the presence of specific substances.

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Enzymatic Labeling in ELISA

In an ELISA assay, the antigen or antibody is labelled with an enzyme, which produces a color change as an indicator.

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EAC-Rosette Formation

A test used to determine the absolute number of lymphocytes, particularly T cells, by binding with sheep erythrocytes.

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Immediate-Type Hypersensitivity (IHT)

An immediate allergic reaction mediated by IgE antibodies.

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Delayed-Type Hypersensitivity (DHT)

A delayed allergic reaction mediated by T lymphocytes.

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Clinical Manifestation of Hypersensitivity

Tissue damage caused by excessive immune responses.

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Anaphylaxis

A rapid, life-threatening allergic reaction that can cause widespread inflammation and organ dysfunction.

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Cells involved in a DHT reaction

The cell type involved in carrying out a DHT reaction.

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Hemolytic Disease of the Newborn

A condition that develops in a fetus or newborn when the mother and baby have incompatible Rh blood types.

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IL-5

An interleukin that stimulates eosinophil activation, a type of white blood cell, in allergic reactions.

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Antibody Diversity

The process that generates the wide variety of antibodies, involving genetic recombination.

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Hybridoma Technology

A method used to produce monoclonal antibodies, which are identical antibodies produced by a single clone of B cells.

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Cytotoxicity of T-Killers

The mechanism by which cytotoxic T cells kill infected or cancerous cells through release of cytotoxic enzymes and proteins.

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What cytokine promotes IFN-γ production?

Interleukin 12 (IL-12) is a cytokine that stimulates the production of interferon-gamma (IFN-γ), a key molecule in the immune response to intracellular pathogens.

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Which immunoglobulins have antitumor activity?

IgG and IgM are antibody classes that have been shown to target and neutralize tumor cells. They contribute to the immune system's ability to fight cancer.

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What causes tumor development despite an immune response?

Tumor antigens are molecules expressed by cancer cells that are recognized by the immune system as foreign. The failure to effectively recognize and target these antigens can lead to tumor development.

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What molecule acts as a complement inhibitor?

DAF (Decay Acceleration Factor) is a membrane protein that regulates complement activation by hastening the decay of C3 and C5 convertases. This prevents the complement system from accidentally attacking host cells.

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How does induced tolerance form?

Induced tolerance is a state of immune unresponsiveness to an antigen that develops later in life, beyond the initial immune system development. It is crucial for maintaining immune homeostasis and preventing autoimmune reactions.

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How are immunoglobulins transported from the blood to mucosal secretions?

Transcytosis is a process of transporting substances, such as immunoglobulins like IgA, across epithelial cell layers. This allows the transfer of these protective molecules from blood to the secretions of mucous membranes.

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Which cells are phagocytic in the body?

Macrophages, neutrophils, and dendritic cells are all phagocytic cells of the human body. They engulf and destroy microorganisms and cellular debris.

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What is the primary function of Th1 cells?

Th1 cells are essential for promoting cell-mediated immunity, which is important for fighting intracellular pathogens. They produce cytokines that activate macrophages and other immune cells.

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Which system does NOT contribute to non-specific defense?

The adaptive immune system, which involves B and T lymphocytes, is a specific defense system that adapts to recognize specific pathogens. It is distinct from the non-specific innate immune system.

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What is true about non-specific defense factors?

Non-specific defense mechanisms, also known as innate immunity, provide immediate protection against pathogens without prior exposure or sensitization. It's the body's first line of defense.

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Which of these is NOT a humoral factor of non-specific defense?

Immunoglobulins, also known as antibodies, are part of the adaptive immune response, not the non-specific defense system. They are highly specific for antigens.

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Which cells are preferentially activated via TLRs?

Toll-like receptors (TLRs) are expressed by various immune cells, including macrophages, dendritic cells, neutrophils, and B cells. They recognize pathogen-associated molecular patterns (PAMPs), triggering the activation of these cells to fight infections.

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What process ensures tolerance to self-antigens in the thymus?

Negative selection is a crucial process that eliminates T lymphocytes during development in the thymus that strongly recognize self-antigens. This prevents the development of autoimmune diseases.

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Which microscopy technique identifies different leukocyte types?

Light microscopy is a common technique used to visualize and differentiate different types of leukocytes (white blood cells) in blood smears. This method helps to determine the relative numbers of different leukocyte types.

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What cells are important for recognizing and killing cells that lack MHC I expression?

Natural Killer (NK) cells are part of the innate immune system and are important for recognizing and killing cells that lack MHC I expression, such as tumor cells and virus-infected cells.

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What molecules present intracellular protein fragments to CTLs?

MHC I (major histocompatibility complex class I) molecules are expressed by most nucleated cells in the body and present peptides derived from intracellular proteins to cytotoxic T lymphocytes (CTLs). This allows CTLs to identify and kill infected or cancerous cells displaying foreign peptides.

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What molecules present processed antigens to Th cells?

MHC II (major histocompatibility complex class II) molecules are expressed by antigen-presenting cells (APCs), such as macrophages and dendritic cells. They present processed antigens, along with costimulatory molecules, to helper T lymphocytes (Th cells) to initiate an adaptive immune response.

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Study Notes

Treatment Methods for Autoimmune Diseases

  • Plasmapheresis removes autoantibodies from the blood, treating autoimmune diseases.

Cytokine Roles in Immune Cell Activation

  • Interleukin-2 (IL-2) is essential for activating and proliferating cytotoxic T lymphocytes.

MHC Expression on Cell Types

  • Class II MHC molecules are primarily expressed on antigen-presenting cells (APCs).

T-Killer Cell Mechanisms

  • Cytotoxic T cells induce apoptosis (programmed cell death) in abnormal cells.

Interferon Production

  • Leukocytes, including dendritic cells, produce interferons in response to viral threats.

Immunoglobulin in Newborns

  • IgG is the immunoglobulin transferred across the placenta to provide passive immunity to newborns.

Antibody Fc Fragment Function

  • The Fc fragment of an antibody interacts with receptors on innate immune cells, such as macrophages and neutrophils, activating them.

Natural Killer (NK) Cell Characteristics

  • NK cells directly kill target cells without phagocytosis, inducing apoptosis.

CD4+ T-cell Activation

  • MHC Class II molecules and co-stimulatory signals from CD80 are needed for CD4+ T cell activation.

B-Lymphocyte Activation

  • The B-cell receptor (BCR) binds to antigens, initiating B cell activation, especially in response to T-dependent antigens.

Antibody Production

  • Plasma cells are differentiated B cells that secrete antibodies.

Complement System Activation

  • The classical complement pathway is triggered by the C1 complex binding to immune complexes.

Regulatory T Cell (Treg) Function

  • Regulatory T cells (Tregs) suppress excessive immune responses and maintain immune tolerance.

CD4 Molecule Binding

  • The CD4 molecule on helper T cells binds to MHC Class II molecules on antigen-presenting cells, initiating an immune response.

Immunoglobulin in Mucosal Secretions

  • IgA is the main immunoglobulin in healthy human upper respiratory tract secretions.

T Cell-APC Interaction

  • The immunological synapse is the contact region where T cells and antigen-presenting cells (APCs) interact to recognize antigens and trigger responses.

T-Killer Cell Interaction

  • T-killer cells interact with MHC Class I molecules (especially during viral infections).

Type I Interferon Function

  • Type I interferons (alpha and beta) are crucial for antiviral immunity by inhibiting viral replication and activating immune cells.

NK Cell Activation

  • NK cell activation happens when they detect the absence of MHC Class I molecules on a cell surface, often indicative of infection or cancer.

B-Cell Marker

  • CD19 is a surface marker specific for B cells.

Th2 Cell Role

  • Th2 cells promote humoral immunity by activating B cells to produce antibodies, and play a role in allergic responses.

TLR (Toll-like Receptor) Function

  • TLRs recognize pathogen-associated molecular patterns (PAMPs) and activate innate immune responses.

Interferon-Gamma Promotion

  • Interleukin 12 (IL-12) promotes the production of interferon-gamma (IFN-γ).

Immunoglobulins in Antitumor Immunity

  • IgG and IgM can be involved in targeting and neutralizing tumor cells.

Tumor Development & Immunity

  • Tumours develop when tumour antigens aren't appropriately recognised or targeted by the immune system, potentially due to immune tolerance or suppression.

Complement Inhibitors

  • DAF (Decay-Accelerating Factor) regulates complement activation by accelerating the decay of C3 and C5 convertases.

Induced Immune Tolerance

  • Induced tolerance is acquired later in life, maintaining immune homeostasis.

Immunoglobulin Transport

  • Transcytosis is the process that moves immunoglobulins, like IgA, across epithelial cells to mucosal secretions.

Phagocytic Cells

  • Macrophages, neutrophils, and dendritic cells are all phagocytic cells involved in eliminating pathogens.

Th1 Cell Function

  • Th1 cells primarily mediate cell-mediated immunity, responding strongly to intracellular pathogens.

Hemolytic Disease of the Newborn

  • Hemolytic disease occurs when Rh-negative mothers develop antibodies against Rh-positive fetal blood cells, damaging fetal red blood cells,.

Eosinophil Activation

  • IL-5 stimulates eosinophil activation in allergic reactions.

Antibody Diversity

  • Recombination of gene segments during B cell development generates the antibody diversity.

Monoclonal Antibody Production

  • Hybridoma technology fuses B cells with myeloma cells to produce monoclonal antibodies.

T-Killer Mechanism

  • T-killer cells kill target cells by releasing perforins (form pores) and granzymes (induce apoptosis), inducing programmed cell death through enzyme perforation.

Non-Specific vs. Adaptive Immunity

  • The adaptive immune system (B and T lymphocytes) is specific, whereas non-specific defense mechanisms (innate) are immediate.

Non-Specific Immune Mechanisms

  • Non-specific defense mechanisms act without prior exposure to a pathogen and involve complement, lysozyme, interferons and inflammatory response.

Toll-like Receptors (TLRs) Activation

  • TLRs activate macrophages, dendritic cells, neutrophils, and B cells to recognize pathogenic patterns (PAMPs).

Immune Tolerance Mechanisms

  • Positive and Negative selection in the thymus ensures tolerance to self-antigens by removing T cells that strongly recognise them.

Leukocyte Identification

  • Light microscopy is used to identify and count leukocytes (e.g., different types of lymphocytes), based on the morphological characteristics of various types of leukocytes in blood smears.

Lymphocyte Markers

  • CD3 and CD19 identify T cells and B cells, respectively.

Functional status of Immune System

  • Serum immunoglobulin levels reflect the status of the humoral immune system.

Immunoassay Techniques

  • ELISA (Enzyme-Linked Immunosorbent Assay) is an immunoassay that uses enzymes as labels, while Radioimmunoassay, Fluorescent Immunoassay and Western Blot are other forms of immunoassays..

Lymphocyte Quantification

  • EAC-rosettes are used to count lymphocytes, particularly T lymphocytes.

Hypersensitivity Types

  • Immediate hypersensitivity (IHT) is mediated by IgE, while delayed hypersensitivity (DHT) involves T lymphocytes.

Hypersensitivity Manifestations

  • Hypersensitivity reactions result in tissue damage due to excessive immune responses.

Anaphylaxis Features

  • Anaphylaxis is a severe and potentially life-threatening allergic reaction that has a rapid onset.

Delayed Hypersensitivity Cell Involvement

  • DHT involves T lymphocytes, particularly CD4+ lymphocytes, triggering cell-mediated immunity.

Rh and ABO Incompatibilities

  • Rh incompatibility is a cause of hemolytic disease in newborns, related to the immune response to Rh factor, leading to damage of fetal red blood cells.

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Test your knowledge on various treatment methods and mechanisms related to autoimmune diseases. This quiz covers topics such as cytokine roles, MHC expression, T-killer cell functions, and more. Dive into the specifics of immune responses and treatments in this comprehensive assessment.

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