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Questions and Answers
What is the primary role of innate immunity?
What is the primary role of innate immunity?
Which cells are primarily responsible for phagocytosis?
Which cells are primarily responsible for phagocytosis?
What defines adaptive immunity?
What defines adaptive immunity?
Which of the following is NOT a component of the innate immune response?
Which of the following is NOT a component of the innate immune response?
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What is the function of Toll-like receptors (TLRs) in the immune system?
What is the function of Toll-like receptors (TLRs) in the immune system?
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Which type of white blood cell is primarily involved in combating parasitic infections?
Which type of white blood cell is primarily involved in combating parasitic infections?
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What is the role of dendritic cells in the immune system?
What is the role of dendritic cells in the immune system?
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Which structure in the immune system helps trap or kill microbes?
Which structure in the immune system helps trap or kill microbes?
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What is a characteristic of phagocytosis?
What is a characteristic of phagocytosis?
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Which component of blood is primarily responsible for blood clotting?
Which component of blood is primarily responsible for blood clotting?
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What is the primary function of antibodies in the immune response?
What is the primary function of antibodies in the immune response?
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Which cells are primarily responsible for extracellular killing of infected cells?
Which cells are primarily responsible for extracellular killing of infected cells?
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What type of immunity is developed when memory cells form clones in response to an infection?
What type of immunity is developed when memory cells form clones in response to an infection?
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Which type of lymphocytes matures in the thymus?
Which type of lymphocytes matures in the thymus?
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What is an epitope?
What is an epitope?
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Which of the following is NOT a class of immunoglobulin expressed by B cells?
Which of the following is NOT a class of immunoglobulin expressed by B cells?
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What mechanism do antibodies use to neutralize viruses?
What mechanism do antibodies use to neutralize viruses?
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What distinguishes natural killer lymphocytes from other immune cells?
What distinguishes natural killer lymphocytes from other immune cells?
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The process of immobilizing pathogens through NETS is primarily associated with which type of cells?
The process of immobilizing pathogens through NETS is primarily associated with which type of cells?
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Which of the following statements about passive immunity is true?
Which of the following statements about passive immunity is true?
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Study Notes
Agricultural Microbiology - Course Outline
- Course code: MICR20010
- Lecturer: Dr. Tadhg Ó Cróinín
Remaining Lectures
- Lecture 10: Microorganisms and Disease
- Lecture 11: The Immune System
- Lecture 12: Pathogenic Bacteria
- Lecture 13: Pathogenic Fungi and Viruses
- Lecture 14: Antibiotic Resistant Microorganisms
- Lecture 15: Microbiology in the Food Industry (including Fungi)
- Lecture 16: Microbiology in the Food Industry (Fermentations)
- Lecture 17: The Nitrogen Cycle
Immunity Concepts
- Susceptibility: Lack of resistance to disease
- Immunity: Ability to ward off disease
- Innate immunity: Defenses against any pathogen (active immediately after infection); includes physical barriers like skin, and chemical secretions that trap/kill microbes. All animals have innate immunity.
- Adaptive immunity: Immunity/resistance to a specific pathogen (develops after exposure to a pathogen); only found in vertebrates.
Immune System vs. Pathogens
- Pathogens are disease-causing agents that infect a wide range of animals, including humans.
- The immune system identifies and responds to foreign bodies (e.g., pathogens) by producing immune cells and proteins.
Innate Immunity
- Present before exposure to pathogens.
- Effective from birth.
- Involves nonspecific responses to pathogens.
- Consists of external barriers (e.g. skin, mucous membranes) and internal cellular and chemical defenses (e.g., phagocytes, antimicrobial proteins).
- Mucus membranes trap bacteria and move them away from the body.
Adaptive Immunity
- Develops after exposure to agents (like microbes,toxins).
- Vertebrates have adaptive immunity.
Formed Elements in Blood
- Red Blood Cells (Corpuscles): Transport oxygen (O2) and carbon dioxide (CO2).
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White Blood Cells: Different types with varied functions:
- Neutrophils: Phagocytosis (engulf and destroy pathogens)
- Eosinophils: Kill parasites
- Monocytes: Phagocytosis (become macrophages)
- Dendritic cells: Phagocytosis, stimulate development of adaptive immunity
- Natural killer (NK) cells: Destroy target cells (e.g., infected cells)
- T cells: Cell-mediated immunity
- B cells: Produce antibodies
- Platelets: Blood clotting
Phagocytosis
- A white blood cell engulfs a microbe.
- Different types of phagocytic cells:
- Neutrophils: Engulf and destroy pathogens
- Macrophages: Found throughout the body and engulf pathogens
- Dendritic cells: Stimulate development of adaptive immunity
- Eosinophils: Discharge destructive enzymes.
- Phagocytosis is a process involving phagocytic cells, lysosomes, and vacuoles. Pathogens are engulfed and digested.
Extracellular Killing by Leukocytes
- Eosinophils and natural killer (NK) cells are involved.
- Neutrophils also play a role in extracellular killing.
- NK cells secrete toxins onto the surface of infected cells.
- NK cells can distinguish normal from infected cells through membrane proteins.
2nd Line of Defense (Neutrophils)
- Neutrophils have enzymes to generate O₂ and H₂O₂ then converted to hypochlorite.
- Neutrophils produce nitric oxide, a chemical that contributes to inflammation.
- Neutrophils can form NETs (neutrophil extracellular traps).
- Neutrophils can kill microbes through immobilization.
Adaptive Immunity Receptors
- The adaptive immune response relies on lymphocytes (white blood cells).
- T cells: Mature in the thymus.
- B cells: Mature in bone marrow.
- Antigens: Substances that elicit a response from B or T cells.
- Exposure to pathogens activates B and T cells with antigen receptors.
- Epitopes: The accessible part of an antigen that binds to an antigen receptor.
Antibody Function
- Antibodies mark pathogens for destruction (opsonization).
- In neutralization, antibodies bind to viral surface proteins, preventing host cell infection.
- Antibodies may bind to pathogens to prevent them from entering cells.
B Cells and Antibodies
- B cells express five forms of immunoglobulin (Ig) with various heavy chain regions.
- IgD: Membrane bound
- IgM: First soluble class produced
- IgG: Second soluble class; most abundant
- IgA and IgE: Remaining soluble classes
Active and Passive Immunization
- Active immunity: Develops naturally after infection or through vaccination.
- Passive immunity: Antibodies are directly donated.
- Immunization involves using a nonpathogenic form of a microbe or part to elicit an immune response with immunological memory.
Vaccines
- Vaccines are harmless derivatives of pathogenic microbes.
- Vaccines stimulate the immune system to create defenses against the harmful pathogen.
- Vaccines can prevent certain diseases.
Measles in the US (1960-2007)
- Historical data shows a correlation between vaccine availability and decreased measles cases in the US.
Vaccine Hesitancy and Effectiveness (Pertussis Cases)
- Graph showing reported pertussis cases since 1922.
- Shows impact of introducing DTP vaccination.
Covid-19 Vaccine Market
- The Covid-19 vaccine market is valued at 10 billion USD annually.
- Much of the research behind Covid-19 vaccines has been funded by governments.
- There are concerns about the duration of natural immune responses and vaccine-triggered immunity.
Brief History of Coronaviruses
- Timeline displays key discoveries/emergences of various coronaviruses (including SARS-CoV-2).
- Key events/discoveries are highlighted along the timeline.
Vaccine Basics, Coronavirus Infection and Immunity
- Diagrams/Illustrations showing the stages of virus entry, viral replication, and the immune response (with B cells, antigen presenting cells).
Nucleic-Acid Vaccines
- Describes DNA and RNA vaccines.
- Illustrates the process of creating the vaccines.
- Includes details on viral proteins and mRNA.
Covid-19 Vaccine Success
- Pfizer/BioNTech vaccine trials show high effectiveness (approximately 90%).
Pathogenic Bacteria (Next Topic)
- The next topic in the course is pathogenic bacteria.
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