Kuby Chapters: Immunology Flashcards
How are the innate and adaptive immune systems different?
INNATE: built-in ability to detect and attack pathogens
- Response time: MINUTES / HOURS
- LIMITED SPECIFICITY & DIVERSITY
- MAKES COMPLEMENTS
ADAPTIVE: acquired ability to recognize and destroy pathogens
- Response time: DAYS
- HIGHLY SPECIFIC & DIVERSE
- MAKES ANTIGENS
* CREATES MEMORY
What are the components of the innate immune system?
Phagocytes:
- monocytes
- macrophages
- neutrophils
- dendritic cells
Mast Cells
Natural Killer (NK) Cells
- Also includes the other natural defenses like skin, cilia/mucus in the respiratory tract, and digestive enzymes in the stomach.
What are the components of the adaptive immune system?
B CELLS, T CELLS & ANTIGEN-PRESENTING CELLS (MHC)
- T lymphocytes in the tissue between the body’s cells. B lymphocytes, also found in the tissue between the body’s cells. Antibodies in the blood and other bodily fluids
How is the innate immune system activated?
Innate: activated immediately upon detection of damage or infection
- Pattern recognition receptors (PRRs) on phagocytes recognize pathogen-associated molecular patterns (PAMPs) found on microbes and damage-associated molecular patterns (DAMPs) found on aging, dead, or damaged self structures. PRRs target them for destruction.
How is the adaptive immune system activated?
Adaptive: responds after being presented with antigens obtained via the innate system
- When a B or T cell interacts with its specific antigen, it is selected and becomes activated
What happens after the adaptive immune system is activated?
Proliferation: producing a large number of clones
Each clone is reactive against the antigen that initially stimulated the original lymphocyte
What are Antigens?
ANTIGENS: Substances that react with antibodies on B Cells or T Cell Receptors.
- Individual B and T cells each have an individual specificity for a single antigen. This is due to each cell having many copies of a receptor on their surface that only bind to one type of antigen
What are the anatomical barriers that aid the immune system?
SKIN and MUCOSA provide an effective immune barrier between the internal and external environment. Skin acts as not only a physical barrier but also a chemical shield.
What are PAMPs?
Pathogen-Associated Molecular Patterns:
receptors found on unwelcome microbes
What are DAMPs?
Damage-Associated Molecular Patterns:
infected cells send out signals to the immune system alerting it
What are PRRs?
Pattern Recognition Receptors:
located on the macrophages to identify PAMPs
What is a MAC?
Membrane Attack Complex:
comes from the complement system and punches a hole in bacteria to kill it through osmosis
What is a Complement?
A series of proteins that will activate whenever a microbe comes in.
A cascade system that enhances antibodies and phagocytes.
What is Inflammation? Describe the process of Inflammation.
- A non-specific reaction to noxious stimuli
- Mast cells release histamines, causing an increase in blood flow resulting in swelling and redness
- Cytokines are released increasing immune response.
- Pro-inflammatory cytokines and chemokines (Cell signaling molecules) are triggered by innate responses to infection, damage, or harmful substances –> Recruitment of neutrophils and other leukocytes from the blood to the site of damage/infection
What are antibodies? How are they produced? What are their characteristics?
ANTIBODIES: blood proteins that control and stop antigens
- Secreted by B (plasma) Cells
- Characterized by heavy (stem) and light (arms) chains (Y!)
- Two binding sites allow antibodies to stop antigens in the blood stream
What are immune cells? How are they produced?
Lymphocytes (T cells, B cells, and NK cells), neutrophils, and monocytes/ macrophages
- All cells of the immune system are CREATED IN BONE MARROW from a common type of starting cell, called a STEM CELL. These stem cells later develop into specific cell types, including red blood cells, platelets (important for blood clotting), and white blood cells (important for immune responses).
What are the Primary and Secondary Lymphoid Organs?
PRIMARY LYMPHOID ORGANS: include the bone marrow and the thymus. They create special immune system cells called “Lymphocytes” (T CELLS & B CELLS)
SECONDARY LYMPHOID ORGANS: These organs include the lymph nodes, the spleen, the tonsils and certain tissue in various mucous membrane layers in the body. TRAP ANTIGEN
Where do T Cells & B Cells go to mature?
T Cells: Thymus
B Cells: Secondary Lymphoid Organs
What are T Cells? What are the different kinds of T Cells and what are their functions?
Helper T Cells (Th): stimulates B and T cell activity (with viral/microbial specific antigen)
Cytotoxic T Cells (Tc): kills infected cells
What are Toll-like Receptors? What is their function?
A specific type of Pattern Recognition Receptors; membrane-bound on macrophages and dendritic cells; part of the innate immune system
They recognize microbes that are trying to gain access to the cell or damaged self-tissue and initiate the immune response and inflammation.
What is the Thymus?
The organ primarily responsible for the production and maturation of immune cells (between lungs).
- Thymus produces mature T cells which upon reinfection will have many available T Cells
What is the difference between a primary immune response and a secondary immune response (with memory)?
A primary immune response results in the generation of memory immune cells. A secondary immune response occurs as a result of a second exposure to an antigen. It is a much more rapid and sustained response due to the action of memory immune cells
How is immunological memory achieved?
- B Cells express a diversity of cell-surface antibodies
- A foreign antigen interacts with one B Cell and that cell divides to form a population of clones
- The B Cell clones differentiate into plasma cells that secrete antibodies AND memory cells with cell-surface antibodies
How do pathogens evade the immune system? How do our cells recognize these pathogens?
One way in which an infectious agent can evade immune surveillance is by ALTERING ANTIGENS.
- Our cells recognize these pathogens with receptors that bind features of these regular patterns; these receptors are sometimes known as PATTERN-RECOGNITION RECEPTORS (PRRs)
