Immunology Quiz: Antibodies and the Immune System

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Questions and Answers

What is the primary role of antibodies in the immune system?

To stimulate the production of autoantigens

To produce immunogens

To directly attack foreign substances

To bind to antigens and help neutralize them (correct)

Which statement accurately defines an allergen?

A foreign substance that leads to an allergic reaction (correct)

A substance that causes an autoimmune disease

A macromolecule that elicits an immune response

A substance that stimulates the production of antibodies

What distinguishes the innate immune system from the adaptive immune system?

The innate immune system is not influenced by previous infections (correct)

The innate immune system evolves with new infections over time

The innate immune system responds later than the adaptive immune system

The adaptive immune system is fully developed at birth

In the context of immunology, what is an autoantigen?

The body's own antigens targeted in autoimmune response Signup and view all the answers

Which statement best describes an antigen?

A foreign macromolecule that can elicit an immune response Signup and view all the answers

What are the small proteins that act as chemical mediators in the immune response called?

Cytokines Signup and view all the answers

Which type of interferons primarily activates antiviral immune responses?

Type I interferons Signup and view all the answers

What is the role of chemokines in the immune response?

They attract immune cells to the site of infection. Signup and view all the answers

What do Toll-like receptors (TLRs) recognize to trigger an immune response?

Damage-associated molecular patterns (DAMPs) Signup and view all the answers

Which cytokine is critical for stimulating immune-cell proliferation and activating inflammatory responses?

Tumor necrosis factor (TNF) Signup and view all the answers

What type of vaccine involves living nonvirulent strains of a microorganism?

Attenuated microbe Signup and view all the answers

Which immune assay involves the use of antibodies against a pathogen?

ELISA Signup and view all the answers

Which statement about innate immune responses is NOT true?

They are specific to an antigen. Signup and view all the answers

What is NOT a characteristic of toxoids used in vaccinations?

They provide protection from the antigen. Signup and view all the answers

What is the correct definition of an antigen?

A macromolecule that can elicit an immune response. Signup and view all the answers

Which type of hepatitis is most likely transmitted via needle stick from an intravenous drug addict?

Hepatitis B Signup and view all the answers

What does the presence of HAV Ab(IgM) suggest in the laboratory serology tests?

Recent exposure to hepatitis A Signup and view all the answers

Given the laboratory serology results, what can be inferred about the likelihood of the guard acting as an infective carrier of hepatitis A?

He is past the peak of infectivity. Signup and view all the answers

Which serology result indicates that the individual does NOT have an active hepatitis B infection?

HBsAg Negative Signup and view all the answers

Which hepatitis viruses could potentially be transmitted if the serum contains HBV and one gets exposed to an intravenous drug user?

Hepatitis B and C Signup and view all the answers

Which of the following substances is NOT found in the blood-brain barrier?

Fingernail Signup and view all the answers

Which of the following is NOT a class of antibody?

IgH Signup and view all the answers

Where do B-cells primarily attack non-self antigens?

Outside the cell Signup and view all the answers

Antibodies are produced by which type of cells?

B cells Signup and view all the answers

Complement is involved in which type of defense?

Both Signup and view all the answers

Is inflammation the body’s natural reaction against injury and infection?

True Signup and view all the answers

What is the most likely cause of vomiting and diarrhea (D&V) in the case of the young child and two neighbours?

Viral infection Signup and view all the answers

If all usual bacterial pathogens have been ruled out, what does this suggest about the cause of the illness?

It is likely viral in nature Signup and view all the answers

What type of testing should always be performed during a suspected outbreak of gastrointestinal illness?

Viral investigation of faeces Signup and view all the answers

Which of the following viruses are detected using reverse-transcriptase real-time PCR?

Norovirus and Adenovirus Signup and view all the answers

Which hepatitis viruses are most likely to be transmitted via a needle stick injury?

Hepatitis B and D Signup and view all the answers

What is an unlikely route of transmission for hepatitis A?

Needle stick injury Signup and view all the answers

What was the presenting symptom that indicated the male security guard might have hepatitis?

Dark urine and jaundice Signup and view all the answers

Regarding the incubation period of hepatitis A-E, which range is accurate?

15 days to 180 days Signup and view all the answers

What could be ruled out as a potential source of the guard's hepatitis given his history?

Travel outside the US Signup and view all the answers

What symptom typically would not be associated with hepatitis A?

Chronic carrier state Signup and view all the answers

Study Notes

Lecture 8: Introduction to Clinical Virology & Immunology

Learning Objectives: Understand viral pathogenesis, common viral infections, laboratory techniques in clinical virology, and basic immunology in the context of infection.
Clinical Virology: The study of viruses and their impact on human health, encompassing diagnosis, treatment, and prevention of viral diseases. It's critical for public health enabling early detection of infections, development of tests, therapies, and vaccines. Clinical virology also helps understand viral evolution, transmission, and emerging pathogens.
Viral Pathogenesis: Host cells respond to viral infections in three ways: no effect (asymptomatic), cytopathic (morphological changes due to viral replication and cell death), and oncogenic (loss of cell replication control). Viral infections can cause localized or disseminated disease. Virus entry can spread through the bloodstream (viremia).
Diagnostic Methods (Virology): Testing methods are grouped into three categories: Direct Detection (electron microscopy, antigen detection -immunofluorescence, histological changes), Indirect Examination (virus isolation), and Serology (measuring antibodies). Viruses cannot be cultured on artificial media.
Molecular Detection: Techniques depend on whether the virus has DNA or RNA genomes. These methods usually involve sample collection, sample processing, viral isolation, RNA extraction (if RNA genome), creating cDNA (if RNA genome), and amplifying the DNA/RNA using PCR.
Serology: Detecting antibodies to specific viruses. The first antibody to appear is IgM. Later, IgG antibodies develop. Serology can identify a past or present viral infections.
Immune Response: Immunology studies the body's genetic, biological, chemical, and physical characteristics. Immunity is a body's ability to respond to foreign substances.
Immunology Key Terms:
- Immunity: The body's ability to respond to foreign substances.
- Immunocompetent: When the immune system functions correctly.
- Immunosuppressed: When part of the immune system cannot respond to challenges.
- Antigen: Any molecule triggering an immune response.
- Epitope: The smallest part of an antigen binding to an antibody.
- Antibody: Protective proteins that target foreign substances.
- Immunogen: Any molecule capable of stimulating antibody production.
- Allergen: A substance causing an allergic reaction.
- Autoantigen: Self-antigens targeted by the immune system (causing autoimmune disease).
- Tumor antigen: Protein on cancerous cells.
Innate Immunity: The body's first line of defense against pathogens. Rapid and non-specific response, Cells involved include phagocytes, monocytes (macrophages), mast cells, neutrophils, dendritic cells, natural killer cells, basophils, and eosinophils.
Innate Immunity—Complement System: Proteins produced by the liver, circulating in the blood until they encounter pathogens, working collectively to destroy them. Three complement pathways—classic, alternative, lectin—are based on distinct triggers (antibody-antigen interactions, pathogen surface molecules, and mannose-binding lectin).
Innate Immunity—Other Key Proteins (TL-Receptors): A family of transmembrane receptors (TLRs). They identify Pathogen-Associated Molecular Patterns (PAMPs) and Damage-Associated Molecular Patterns (DAMPs) (from dying cells) triggering inflammation.
- Cytokines: Small proteins mediating the immune response. Types include Colony-Stimulating Factors (CSF), Interferons, Interleukins (IL), Chemokines and Tumor Necrosis Factor (TNF).
Acute Inflammation: A protective mechanism triggered by injury or infection.
Acute vs Chronic Inflammation: Differentiated by type of initiating cells, the duration of the response, and the severity and progression of the inflammatory response.
Adaptive Immunity: This type of immunity is the body's acquired immunity. It develops later in life and adapts to new infections, requiring antigens, cells (B-cells and T-cells), antibodies, receptors, and immune responses.
- Antigens: Any foreign macromolecule specifically recognized by the immune system.
- Antibodies: Proteins produced by B-cells to specifically bind to antigens.
- B-cells: Develop in the bone marrow, producing antibodies directed against specific antigens.
- T-cells: Crucial for cell-mediated immunity. Recognize antigens presented on cells.
Antibodies: Types such as IgM, IgG, IgA, IgD, IgE and how they function
T Cell-Dependent Activation of B cells: How B-cells are activated when a helper T-cell assists.
T Cell-Independent Activation of B cells: How B-cells become activated even without assistance from T-cells.
Case Studies: Examples of different viral infections and potential tests to determine the causative agent.
Vaccination: An artificially acquired active immunity which strengthens the immune system's response against the antigen.
- Types of vaccines: Attenuated microbes, killed or fragmented microbes, and toxins.

Specific Cases

Viral Gastroenteritis (Case 1): Viral cause (likely Norovirus) suspected due to multiple simultaneous illnesses seemingly linked to a common source (a birthday party and swimming pool).
Hepatitis (Case 2): Hepatitis B, C, or D are possible diagnoses, considering the needle-stick exposure. The serology test results are critical for diagnosis, especially the IgM.

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Description

Test your knowledge on the role of antibodies and various components of the immune system with this quiz. Explore key concepts such as innate vs. adaptive immunity, allergens, and vaccine types. Perfect for students of immunology or anyone interested in understanding how our immune system functions.