HRR: introduction to the immune system Flashcards
Generally, how does the immune system defend against extracellular/mucosal threats?
Soluble proteins and phagocytic cells
Generally, how does the immune system defend against intracellular threats?
Specialized cells that kill each other via cell signaling or cell-cell contact
List the 3 major components of the immune system
Leukocytes, lymphoid tissue, and secreted proteins
What are the general functions of leukocytes in the immune system
They’re the weapons and soldiers of the immune system; they detect, neutralize, and eliminate various threats
What are the general functions of lymphoid tissue
They’re the training camps and forts; the generate, support, and store leukocytes
What are the general functions of secreted proteins
They’re the communicators and have a minor weapon role; they can activate systemic defenses, directly neutralize toxins, participate in cell-cell communication, and activate/coordinate/mature/differentiate leukocytes
Where are most of the white blood cells found?
In lymphoid tissues!
What are the primary lymphoid organs
Thymus and bone marrow
What are the secondary lymphoid organs
Spleen, lymph nodes
Compare the innate and adaptive immune responses in terms of speed
Innate immunity is much faster than adaptive immunity. Innate takes minutes to hours, while adaptive takes days to weeks
Compare innate and adaptive immune responses in terms of memory
The innate immune system has no memory, meaning there is no improvement in response with subsequent encounters. The adaptive immune system has memory, meaning the immune response is faster and stronger with each subsequent encounter
What are some innate defenses
Epithelial, chemical barriers, granulocytes, NK cells, and complement
What are antigen presenting cells?
Cells in the innate immune system that spread out in tissues and monitor for threats; big examples include macrophages and dendritic cells
Explain the difference between pathogen-and damage-associated molecular patterns (PAMPs and DAMPs) and antigens
PAMPS are molecules found in pathogens but not our cells, and DAMPs are molecules normally found inside the cell but instead are on the outside
What components are recognized by the innate and adaptive immune systems to signal threats?
The innate immune system recognizes PAMPs and DAMPs, while the adaptive immune system recognizes antigens
Briefly compare the cells of the innate and adaptive immune systems
The cells in the innate immune system are released from bone marrow fully functional and ready, and do not divide once out of the bone marrow. Cells of the adaptive immune system, proliferate and differentiate after encountering antigen before they are considered functional
Explain the relationship between immature, mature, activated, effector and memory lymphocytes.
Immature: freshly made from hematopoietic stem cells
Mature naïve: has gained a unique antigen receptor, but has not encountered the antigen
Activated: the lymphocyte encounters the antigen and proliferates. Innate immune signals will allow for differentiation into specific effector lymphocytes. Memory lymphocytes will also be formed
what are the two major effector mechanisms employed by the immune system to destroy infectious agents and abnormal cells?
antibodies and T cells
describe T cells: what they do, how they do it, and what they’r effective against
- kill cells by touching them
- Its receptors recognize foreign antigen on a cell, perforin pierces it and allows T cell enzymes to enter the cell, and the cell destroys itself from the inside out.
- they’re effective against tumors and intracellular microbes.
describe antibodies
made by B cells. They have 2 light and 2 heavy chains bonded by disulfide bonds. They have variable regions that stick to antigens and a constant region that can interact with leukocytes and innate soluble proteins.
list the 5 different antibodies
IgG: phagocytes
IgM: complement
IgD: B-cell activating receptor
IgA: secreted into mucus
IgE: binds to mast cells and eosinophils
What are plasma cells?
Cells in the bone marrow that are differentiated B cells. They make the same antibody for life, but do not respond to antigen
How do antibodies protect us?
Activate complement, block bacteria and viruses from attaching to our cells (IgA in blood, IgM in mucus), opsonization (aka increased phagocyte capture and destroy abilities), activate eosinophils and basophils
How can the innate immune system steer antibody production
the release of cytokines
Explain the difference between passive and active immunity
Active immunity is when a person develops antibodies/T cells themselves after vaccine or infection. Passive immunity is when someone is injected with T cells or antigens. Active takes longer but lasts longer, while passive is fast but temporary
describe humoral immunity
describe cellular immunity
what recognizes PAMPS in the innate immune system
pattern recognition sequences
