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Questions and Answers
Which type of vaccine uses living nonvirulent strains of a microorganism?
Which type of vaccine uses living nonvirulent strains of a microorganism?
Viruses can be cultivated on artificial media.
Viruses can be cultivated on artificial media.
True
What is an antigen?
What is an antigen?
Any macromolecule that can elicit an immune response
Altered toxins that provide protection from toxin but not the antigen itself are called ______.
Altered toxins that provide protection from toxin but not the antigen itself are called ______.
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Match the following vaccine types with their descriptions:
Match the following vaccine types with their descriptions:
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What is the primary focus of clinical virology?
What is the primary focus of clinical virology?
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Cytopathic effect in viral infection always results in cell death.
Cytopathic effect in viral infection always results in cell death.
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Name one category of diagnostic methods in virology.
Name one category of diagnostic methods in virology.
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Following viral exposure, antibodies will first appear as __________.
Following viral exposure, antibodies will first appear as __________.
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Match the following patterns of viral infection with their descriptions:
Match the following patterns of viral infection with their descriptions:
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Which technique for molecular detection of viral genomes is less commonly performed now?
Which technique for molecular detection of viral genomes is less commonly performed now?
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Serology is used for the direct detection of viral infections.
Serology is used for the direct detection of viral infections.
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What is the role of clinical virology in public health?
What is the role of clinical virology in public health?
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What is the first step in the T cell-dependent activation of B cells?
What is the first step in the T cell-dependent activation of B cells?
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The primary immune response occurs immediately after exposure to an antigen.
The primary immune response occurs immediately after exposure to an antigen.
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What are the two types of cells that B cells can differentiate into after activation?
What are the two types of cells that B cells can differentiate into after activation?
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Maternal immunoglobulins primarily consist of _____ and provide passive immunity to the infant.
Maternal immunoglobulins primarily consist of _____ and provide passive immunity to the infant.
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What type of immunity is developed through vaccination?
What type of immunity is developed through vaccination?
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Match the following terms with their definitions:
Match the following terms with their definitions:
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What happens to the antibody titer during the secondary immune response?
What happens to the antibody titer during the secondary immune response?
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Helper T cells play a crucial role in activating B cells through cytokine secretion.
Helper T cells play a crucial role in activating B cells through cytokine secretion.
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Which of the following is NOT a class of antibody?
Which of the following is NOT a class of antibody?
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B-cells attack non-self antigens outside the cell.
B-cells attack non-self antigens outside the cell.
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What type of cells produce antibodies?
What type of cells produce antibodies?
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Complement is involved in _____ defense.
Complement is involved in _____ defense.
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What is the body's natural reaction against injury and infection?
What is the body's natural reaction against injury and infection?
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Match the following components to their respective functions:
Match the following components to their respective functions:
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What is the most likely cause of D&V in the case study presented?
What is the most likely cause of D&V in the case study presented?
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The three children likely contracted the illness from _____ at the birthday party.
The three children likely contracted the illness from _____ at the birthday party.
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Which types of hepatitis could be most likely acquired through a needle stick from an intravenous drug addict?
Which types of hepatitis could be most likely acquired through a needle stick from an intravenous drug addict?
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Hepatitis A is commonly transmitted via the fecal-oral route.
Hepatitis A is commonly transmitted via the fecal-oral route.
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What does a positive Hepatitis A IgM antibody indicate?
What does a positive Hepatitis A IgM antibody indicate?
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The guard is past the period of peak infectivity for Hepatitis A because he has developed ______ antibodies.
The guard is past the period of peak infectivity for Hepatitis A because he has developed ______ antibodies.
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Match the following laboratory results with their significance:
Match the following laboratory results with their significance:
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Which hepatitis types are most likely to be transmitted via a needle stick from an intravenous drug addict?
Which hepatitis types are most likely to be transmitted via a needle stick from an intravenous drug addict?
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Hepatitis A is usually transmitted via the parenteral route.
Hepatitis A is usually transmitted via the parenteral route.
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What is the causative agent identified in the case study of the outbreak of diarrhea and vomiting?
What is the causative agent identified in the case study of the outbreak of diarrhea and vomiting?
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The incubation time for hepatitis A-E ranges from approximately ___ days to ___ days.
The incubation time for hepatitis A-E ranges from approximately ___ days to ___ days.
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Match the hepatitis types with their usual transmission routes:
Match the hepatitis types with their usual transmission routes:
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What symptom did the security guard NOT report after the needle stick incident?
What symptom did the security guard NOT report after the needle stick incident?
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The security guard had a history of drug abuse.
The security guard had a history of drug abuse.
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What was the consequence concerning the guard's liver as reported in the case study?
What was the consequence concerning the guard's liver as reported in the case study?
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Study Notes
Introduction to Clinical Virology & Immunology
- Lecture 8, presented by Dr. Claire Atkinson, covers clinical virology and immunology.
- Learning Objectives include understanding viral pathogenesis, common viral infections, laboratory techniques in clinical virology, and fundamental immunology in the context of infection.
- Clinical virology is the study of viruses and their impact on human health. It involves virus diagnosis, treatment, prevention of viral illness.
- Clinical virology is essential for public health as it enables early detection of infectious diseases, development of tests, therapies, and vaccines.
- Clinical virology supports the understanding of viral evolution, transmission, and emerging pathogens.
Viral Pathogenesis
- Host cells respond to viral infections in three ways:
- No effect – asymptomatic infection
- Cytopathic effect and cell death – morphological changes due to viral replication
- Loss of control of cell replication – oncogenic viruses
- Host viruses can cause three infection patterns
- No clinical signs
- Localized infection
- Disseminated infection
- Viral entry is spread via bloodstream, lymph nodes, and to target organs (viraemia)
Diagnostic Methods in Virology
- Tests are grouped into 3 categories:
- Direct Detection
- Indirect examination (virus isolation)
- Serology.
- Viruses cannot be typically grown on artificial media.
Direct Detection
- Electron Microscopy – identifies viruses based on morphology (size, shape).
- Antigen detection – immunofluorescence staining used to identify viral antigens.
- Histological changes – detecting characteristic changes in infected cells. (e.g., cytomegaloic inclusion bodies, 'owl's eyes' ).
Molecular Detection of Viral Genomes
- Techniques depend on whether DNA or RNA genomes are present
- Steps typically involve:
- Sample collection followed by collection.
- Sample isolation via buffer.
- Viral detection via virus isolation.
- RNA extraction
- Conversion of isolated viral RNA to cDNA
- PCR amplification (polymerase chain reaction)
Serology
- Detecting antibodies as an indirect measure of infection
- Provides information on past/current infection.
- Measures IgM (first response) and IgG (later response) antibodies against specific viruses.
- A combination IgG/IgM test helps evaluate antibody responses.
What is the Immune Response?
- Immunology is the study of the genetic, biological, chemical and physical characteristics of the Immune System.
- Immunity is the body's ability to respond to foreign substances.
- Immunocompetent means the immune system works as it should.
- Immuno-suppressed means part of the immune system is not working as normal.
- Antigens are macromolecules that trigger an immune response. An epitope is the smallest part of an antigen that can bind to the antibody.
- Antibodies (immunoglobulins) are protective proteins produced by the immune system in response to the presence of antigens.
- Immunogens are macromolecules that stimulate antibody production.
- Allergens are substances that trigger allergic reactions.
- Autoantigens are self-antigens targeted by the immune system.
- Tumour antigens are present on tumour cells.
- Innate Immunity is the initial response to various pathogens. It's usually fast (within hours). It's not specific, so it acts in a non-specific way. Memory is also not involved.
- Adaptive Immunity takes time (days) to respond to foreign substances or infections and is usually very specific to the foreign substance. There is usually memory.
Innate Immunity
- The most basic defense mechanisms of the body are used as a very general way to fight off any potential infection or threat.
- Physical Barriers - Skin, tears, saliva, and mucus membranes provide a first line of defense against pathogens.
- Cells of the innate immune system:
- Phagocytes, including monocytes, and macrophages, engulf and destroy pathogens (engulfing)
- Mast cells release histamine, aiding inflammation.
- Neutophils, phagocytes, (similar to macrophages) - are the most abundant phagocytes.
- Dendritic cells are responsible for capturing antigens in tissues and transporting them to lymph nodes for antigen presentation.
Innate Immunity- Complement System
- Complement proteins are produced in the liver and circulate in the blood until triggered to attack pathogens.
- Complement proteins complement the work of antibodies.
- 3 pathways of complement action exist:
- Classic- triggered by antibodies
- Alternative- triggered by cell surface molecules.
- Lectin- triggered by pathogen-binding lectin.
Innate Immunity - Other Key Proteins
- Toll-like receptors (TLRs) are important transmembrane proteins that act as the first line of defense against microbes.
- These signal the immune system to initiate an appropriate response when TLRs are activated.
Cytokines
- Small proteins that act as chemical mediators in the immune response.
- Different cytokines have various functions in the immune system. These include cell development and differentiation.
Acute Inflammation
- A protective mechanism that occurs after injury or when microbes enter damaged tissue.
- Physical, chemical or microorganism initiated injury triggers inflammation.
- Events in inflammation include:
- Increased blood flow
- Leakage of fluid
- Cell recruitment to the injured area
- Redness, swelling, heat, and pain.
Acute vs Chronic Inflammation
- Acute inflammation is short-term, usually resolving quickly, whilst chronic inflammation is prolonged with possible increased cell recruitment and tissue damage.
Adaptive Immunity
- The second line of defense against pathogens that the body has established. It's a response that is usually very specific and often slower (days-weeks) to initiate the response compared to the innate immune system.
- The role of adaptive immunity includes the recognition of 'self' from 'non-self'.
- Antigens are any macromolecule recognized by the adaptive immune system as 'non-self'.
- Cells that carry out the adaptive immunity include B cells, developed in the bone marrow, and T cells involved in directly attacking antigens as well as stimulating (supporting) other immune cells.
Antibodies
- Antibodies (immunoglobulins) are proteins produced by B-lymphocytes in response to foreign antigens.
- Different classes of antibodies contain different functions.
- IgM is usually the first antibody produced in response to infection, and usually is the largest antibody.
- IgG is the most abundant antibody class and is also able to cross the placenta.
T-Cell Dependent Activation of B Cells
- Activation process for B cells that need help from T cells
- The process involves the presentation of antigens via MHC on B cells, recognition by helper T cells, cell-to-cell interaction between the helper T cell and B cells, B cell activation and proliferation. Creates immune response
- The function and process of the helper T cells and how these cells act to stimulate B cells.
The Immune Response to Infection
- Processes involved in this response include processes in the primary immune response.
Primary and Secondary Antibody Response
- The primary antibody response involves the initial activation and production of antibody class IgM in response to an antigen, followed by a secondary response which is faster and involves switch to IgG antibodies for heightened and faster immune response due to "memory" cells.
Immunity (Humoral): Active/Passive
- Naturally acquired active immunity- occurs when an individual gets infected and recovers, which stimulates long-term protection via the immune response.
- Artificially acquired active immunity- involves vaccines administered with an antigen to gain immunity.
- Naturally acquired passive immunity- occurs when antibodies are transferred from the mother to the baby.
- Artificially acquired passive immunity- occurs when antibodies are transferred directly via injection.
Vaccination
- Involves introducing weakened or inactive forms of pathogens or their components to build immunity without causing disease.
- Types of vaccines include:
- Attenuated microbes – use living, weakened versions
- Protein fragments or killed microbes
- DNA/RNA immunizations – use genes of viral antigen
- Toxoids – inactivate toxins
Immune Assays: Timing
- Timing of diagnostic assays for diseases, particularly those relying on antibodies, is critical in determining if a patient is truly infected. The timing depends on the disease/condition and the specific test(s) used.
Antigen Detection – Agglutination Test
- Test method to identify presence of antigens/antibodies
Immune Assays - ELISA
- Enzyme-linked immunosorbent assay (ELISA) is a test method widely used to detect the presence of antibodies/antigens in a sample
In Clinical Practice – What Test(s) Should I Use for HIV?
- NAT, Antigens/Antibodies lab tests, rapid antigen/antibody tests, antibody tests, each with respective window periods are tested to diagnose HIV
- The window period for these tests refers to the time between infection and when the test can reliably detect the specific pathogen.
Questions
- Includes general questions related to the topics covered during the lectures.
- Note there are specific questions from case study examples.
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Description
Test your knowledge on clinical virology with this quiz, which covers vaccine types, diagnostic methods, immune responses, and viral infections. Challenge yourself with questions that include matching vaccine types and understanding the role of clinical virology in public health.
