Introduction to Immunology - Hinterleitner Flashcards
What are the 4 classes of pathogens?
- Viruses
- Bacteria
- Fungi
- Parasites
What is the strategy of the innate immune system?
Detect conserved molecular patterns common to groups of pathogens.
What is the strategy of the adaptive immune system?
Detect unique components of a particular pathogen.
What are the limitations of the innate immune system (3 things)?
- Fixed recognition strategy
- No memory
- Only limited amplification of the response
How does the adaptive immune system contribute to immunity (4 things)?
- Adds to ongoing innate response
- Highly specific
- Unique receptors by gene rearrangement
- Long-lasting memory
What are the lymphocytes?
B-cells and T-cells
What are B-cells main function?
Produce antibodies
What are T-cells main function?
Kill infected cells and direct innate and lymphocyte responses
What are the limitations of adaptive immunity?
- Slow
- Can be evaded
Where do all immune cells originate?
Hematopoietic stem cells in bone marrow
What are the innate immune cells (7)?
- Macrophages
- Dendritic cells
- Neutrophils
- Eosinophil
- Basophil
- Mast cells
- NK cells
Where do T-cells differentiate?
The thymus
How do lymphocytes encounter pathogens?
They circulate between the blood and peripheral lymphoid tissues until they encounter their antigen
What is the complement system?
Soluble molecules and pattern recognition receptors that detect and destroy pathogens
How does the innate immune system recognize pathogens all throughout the cell?
- Surface - Toll-like, mannose-binding, etc
- Cytoplasmic - CARD-family, Nod-like
- Endosomal - Toll-like
What is clonal selection?
The process by which only B/T-cells with receptors to recognize a specific pathogen out of a pool of many specificities will activate and proliferate.
B-cell Receptors (BCRs)
- Called antibodies or Igs (immunoglobulin)
- Express many copies on the surface
- Recognize whole antigen or intact microbe/protein
Antibody Structure
- 2 binding sites
- Made up of heavy and light chain
What happens when a resting B-cell encounters a pathogen?
Resting B-cells have Igs expressed on their surface. When in contact with a pathogen, they will activate and secrete antibodies (now called plasma cells)
Functions of Antibodies
- Opsonization
- Block toxins
- Direct lysis of bacteria
T-cell receptors
- Only expressed on surface
- Recognize small fragments of pathogens-derived proteins only if they are bound to self, MHC
Summarize T-cell Recognition of Infection
Pathogen-derived proteins will be phagocytosed and degraded. Small fragments will be loaded onto MHC and T-cells will bind.
What are T-cells main function (2)?
- Destroy infected cells
- Direct immune cells in response
Principle of Flow Cytometry
- Detect fluorescently labeled antibodies on the surface of individual cells in a suspension.
- Can identify different cell-types by different fluorescent tags.
-Intensity of color says something about how many of that cell-type are in suspension.
