1- Intro to Immunology Flashcards
Define commensals
Colonize the body surfaces but do not invade the body and don’t normally cause disease
Define pathogen
organism that can cause disease
Define primary pathogen
cause disease every time it invades the body, even in small numbers
Define opportunistic pathogen
cause disease only when administered in high doses
Describe the basic pathway that innate immunity takes when microbial invasion occurs.
- recognition of pathogens (PAMPs) and tissue damage (DAMPs)
- inflammation
- pathogen elimination
Describe the basic pathway that adaptive immunity takes when microbial invasion occurs.
- Antigen capture and processing
- T or B cell activation
- immunologic memory and pathogen elimination
Describe the specific characteristics of innate defense
- protects previously unexposed animal
- immediate protection
- not specific
- activated by PAMPs and DAMPs
- provide important signals for adaptive immune response
Describe the specific characteristics of adaptive defense
- develops days to weeks after exposure
- specific
- memory
- tolerance
- enhance innate immune system response
What are the components (5) of innate defenses?
1) Physical/chemical barriers
2) Phagocytic and sentinel (guard) cells
3) Complement system
4) Innate defence cytokines
5) Natural killer (NK) cells
What are the components of adaptive defense?
1) Humoral immunity (antibodies)
2) Cell-mediated immunity
What are some types of physical/chemical barriers in innate immunity?
- epithelial barriers (skin, mucus membrane)
- Normal microflora
- acid environment in stomach
- antimicrobial peptides
Describe the role of phagocytic and sentinel cells in innate immune response
Phagocytic cells: ingest and kill pathogens (neutrophils and macrophages)
Sentinel cells: resident tissue cells that detect invasion by recognizing PAMPs and DAMPs (Dendritic cells (DC), macrophages, mast cells)
Describe the complement system in the innate immune response.
- an enzyme cascade system that has antimicrobial activity
- series of 20-30 proteins in blood plasma
- rapidly induced
- multiple mechanisms for controlling infection
- potent; harmful if not regulated
What are innate defense cytokines?
Protein messenger molecules that can act on other cells or the cell that produced it
What is the role of proinflammatory cytokines?
secreted by sentinel cells in response to PAMPs and DAMPs, cause fever, lethargy, and loss of appetite
What is the role of chemokines?
Cause cells to migrate to sites of infection, some are produced by sentinel cells
What is the role of interferons?
Interferes with replication of some viruses, produced by virally infected cells
What is the role of natural killer (NK) cells?
Look for the absence of normal in the body
- lymphocyte that is part of innate immunity
- Kill virus-infected cells and tumor cells
- recognize and kill cells that do not express normal proteins
What is the role of Humoral immunity in adaptive defense?
- B cells or B lymphocytes produce antibodies
- Antibody= immunoglobulin= Ig
- examples: IgM, IgG, IgA, IgE
What is the role of cell-mediated immunity (CMI) in adaptive defense?
Two major classes of T cells bases on T- cell receptors
- Alpha-Beta T cells
- Gamma Delta T cells
Adaptive defense has antigen recognition. What does this mean?
- antigen processing cells (APCs)
- APCs- Dendridic cells, macrophages, B-cells
- different from recognition by innate cells
Adaptive defense has immunologic memory. What does this mean?
When the body is exposed to a pathogen for the first time, it will have a sluggish response but, if the body recovers and is exposed to the pathogen a second time, the immune response will be more immediate and larger
Adaptive defense has tolerance. What does this mean?
- protecting ‘self’ from immune system
- can develop against ‘non-self’ antigens too, under certain circumstances
