Week 3: Immune System Flashcards
Innate immunity
Non-specific, built-in mechanism, immediate response
Adaptive immunity
Specific, acquired through active infection or vaccination
Innate immune system examples
Physical defenses
Chemical defenses
Cellular defenses
Inflammatory defenses
B cell
- Matures in bone marrow
- Glycoproteins (antibodies or immuniglobulins) production
- Humoral immunity
- Uses antibody to neutralize pathogen outside of cells.
T cells (helper T cell, cytotoxic T cell)
- Mature in thymus
- Recognize and fight off infections
- Cellular immunity
- Targets primarily intracellular pathogens
- Directly attack or destroy infected cells
- Helper T cell activates B cells immunity
Neutralization
Once antibody binds to an antigen, it can block the pathogen from infecting cells. This process is neutralization
Opsonization
Antibodies can tag/mark pathogens for destruction by other immune cells like macrophages. This process is opsonization
Complement system
A group of proteins that antibodies trigger. Then they destroy pathogens by punching holes in their membrane, causing to break apart.
Agglutination
Antibodies can cause pathogens to clump together, so it will be easy for immune cells to engulf them
Mucocilliary escalator
A Defense mechanism in the respiratory system that helps keep the airways clear of mucus, dust, pathogens, and other particles.
Mast cells
Hematopoiesis produces mast cells, contains histamine, plays a role in allergic and inflammatory responses. Found in tissues rather than in blood circulation.
Chemotaxis
Attraction of immune cells to the infection sites, particularly neutrophils and other white blood cells.
Cytokines
- Small soluable proteins that serve as communication molecules between cells in the immune system.
- Released by immune cells
- Excessive cytokines can cause cytokine storm
Interferons
Cytokine that inhibits viral infection /replication and activates immune cells
Phagocytosis steps
1.Chemotaxis
2. Recognition and attachment
3. Engulfment
4. Phagolysosome formation
5. Destruction and digestion
6. Exocytosis
Chemotaxis
The process by which phagocytes are recruited to the infection site
Signs of inflammation
S: swelling
H: heat
A: altered function
R: redness
P: pain
Inflammation process
- Tissue damage & infection
- Release of inflammatory mediators
- Vasodialation
- Removal of invading microbes
Pyrogen
Fever-inducing chemicals reset brains thermostat, hypothalamus to a higher temperature > fever
3 components of Adaptive Immune System
Specificity
Memory
Tolerance
Free antigens
Free-floating in the environment, only B cells respond to free antigens
Presented antigens
- Only T cells respond to them.
- Presented by immune cells called by antigen presenting cells (APCs)
- APCs include dendritic cells, macrophages and B cells
Epitope
Specific part of a molecule, usually on the surface of an antibody that is recognized by the immune system. It’s like a “flag” that an antibody or immune cell can attach to in order to identify or attack the invader
2 ways of humoral immunity
- T - cell dependent : helper T cell recognized antigen» provides signals ( cytokynes)»_space;activates B cells
- Antigens activates B cells independently. Less common.
B cell differenciation
Once activated, B cells differentiates into
1. plasma cells (produce and secreted large antibodies) or
2. memory B cells (responds upon re-exposure to the same antigen)
Dendritic cells
Innate immune cells. Professional informer. They present these antigens to T cells, activating them to target specific antigens. Important to initiate adaptive immunity
Macrophages
Innate immune cell, engulfs and breaks down pathogens and present their antigens on their surface, activating T cell
Types of cytokines
- Interlukins
- Interference
- Tumor necrosis factors
- Chemokines
Natural Killer Cells
- Innate immunity
- Releases cytotoxic granules»_space;punch holes in target cell membranes»_space; kills infected cells or cancer cells
- Caused apotosis, programmed cell death
