1 - Infectious Agents and Host Immunity Flashcards
What is a normal range for White Blood Cell count?
4.0 - 10 x 10^3 microliters
What is the most numerous type of white blood cell? What does it mean if there’s an increase in this cell type?
Neutrophils are the most abundant WBC type.
An increase in neutrophils is diagnostic for a bacterial infection.
What are the only WBC types that are adaptive immune cells? What are the rest?
Lymphocytes are adaptive immune cells.
Everything else is innate immune cells.
What are the basic three components of immunology when considering any interaction?
Cells and tissues
Soluble mediators
Receptors
What is the physiological function of the immune system?
Prevent infections and eradicate established infections.
What is immunity?
The state of being immune to, or protected from an organism of foreign agent.
What is innate immunity?
Inherent protection against organisms that are permanent from birth and DO NOT CHANGE or adapt to pathogens or foreign agents.
What is adaptive immunity?
DYNAMIC protection that results from specific immune components changing or adapting to unique features of the pathogen of foreign agent.
What decision is made when the immune system decides whether an antigen is self or non-self?
Self: tolerogenic immune response against self - tolerates it
Foreign/non-self: mount an innate or adaptive response
How does the immune system decide to react to self or non-self molecules (ie what types of molecules can be present)?
Antigen (Ag): molecule recognized by antigen receptors
Immunogen: antigen that induces immune response
Tolerogen: antigen that induce immune unresponsiveness to subsequent doses of molecule
What characteristics make something more likely to be an immunogen?
Large Intermediate dosage complex composition bacteria effective interaction with MHC complex.
Rate these locations from most to least immunogenic?
Intravenous
Intragastric
Intraperitoneal
SubQ
SubQ > Intraperitoneal > IV >intragastric
This makes sense because the places that are more immunogenic are where things should NOT be chillin.
How does the innate immune system recognize something as non-self? What is the speed of this?
Via pattern recognition receptors (PRR) with limited diversity.
This is very fast.
How does the adaptive immune system recognize something as non-self? What is the speed of this?
Via antigen receptors expressed on either T or B lymphocytes with nearly unlimited diversity.
Slower than innate immune system.
How does the body respond to an intracellular antigen vs. an extracellular antigen?
Intracellular: cell-mediated immunity - think T cells
Extracellular: humoral immunity - think B cells
What is a primary immune response? What is a secondary immune response? Compare the speeds.
Primary: response to initial exposure to substance - usually slow.
Secondary: more rapid and stronger response to subsequent exposure to substance.
Why do the antibody and effector T cell levels not return to their baseline levels after a primary immune response?
Because the memory lymphocytes are still present.
Within adaptive NATURAL immunity, what are the two types?
Passive: from mom
Active: from infection
Within adaptive ACQUIRED immunity, what are the two types?
Passive: Serotherapy
Active: Vaccination
In terms of adaptive natural immunity, describe passive and active immunity. What are the benefits of each?
Passive: receiving preformed from mom; rapid protection for a short duration.
Active: exposure to foreign antigen during infection; slower protection and longer duration from memory lymphocytes.
In terms of acquired natural immunity, describe passive and active immunity. What are the benefits of each?
Passive: receiving antibodies as therapy for rapid protection. Short duration.
Active: receiving altered foreign antigen during immunization. Slow protection and longer duration from memory lymphocytes.
What is a live attenuated vaccine? What does it induce? What are the pros and cons?
Modified to decrease pathogenicity or limited growth after injection.
Induces CELLULAR response from T cells.
Pro: strong, long-long immunity
Con: may revert to virulent
What is an inactivated vaccine? What does it induce? What are the pros and cons?
Pathogen inactivated by retains an immunologic epitope on surface.
Induces HUMORAL response from B cells.
Pro: stable and safer than live
Can: weaker immunity-requires booster
How is the innate immune system activated?
Pattern recognition receptors recognize molecular patterns (PAMP) on bacteria, virus, fungus, or parasite.
These activate a series of proinflammatory or anti-viral signaling pathways.
NO MEMORY. Response to pathogen will be immediate and same to subsequent infection.
What is the function of the innate immune system?
Provide primary defense against invading pathogens.
Always ON and does NOT require previous exposure for activation.
What are the mechanisms that the innate immune system uses?
Natural barriers - epithelium (skin/mucous membranes)
Phagocytic cells such as macrophages and neutrophils
Dendritic cells
NK cells
Complement pathways
The binding of what activates the adaptive immune system?
Antigen: A molecule that binds to an antibody or T cell receptor.
Epitopes: The specific part of a macromolecular antigen recognized by receptors expressed on lymphocytes
In the adaptive immune system:
What does an antibody (B cell receptor) recognize?
What does a T cell receptor recognize?
Proteins and lipid antigens expressed on naive B cells.
What is the function of adaptive immunity? What are it’s characteristics?
To provide an antigen-specific defense via T and B lymphocytes.
Must be activated by invading antigen to cause a cascade of events.
Allows body to prepare for future via immune memory.
Where in the body are immune decisions made? Give examples.
- Generative immune organs such as bone marrow and thymus
- Peripheral immune organs such as the spleen, lymph nodes, and tonsils
- Peripheral tissues: the site of infection or antigen entry
