Immune System - Innate immunity Flashcards
Non-Specific/Innate Immunity
First-line of defense
Does not need to recognize the pathogen
Same response each tiem it sees a pathogen
Specific/Adaptive Immunity
Requires recognition of the pathogen
Faster response when it sees the same pathogen again
3 Ways scientific dsicoveries are made
1) Accidents of Nature - stroke (realize part of brain was important for something)
2) Leaps of Faith - make observation and decide to carry it further
3) Serendipity - Happy accident
Serendipity example
Alexander Fleming
Discovered Penicillin
Bubble Boy
David Vetter, born 1971
Severe Combined Immune Deficiency Syndrome (SCID)
HIV kills…
Helper T cells
Smallpox and Vaccination
30% of people died who got smallpox
Edward Jenner, 1796
Dairy mades had pox on their hands, from cow pox
Edward took leap of faith
Took pus and put it in a persons arm
1980
Smallpox was eradicated
Ali Maow Maalin
Got saved from smallpox
Last guy who got smallpox
Lymphoid organs
Primary Lymphoid Organs
Secondary Lymphoid Organs
Primary Lymphoid Organs
Sites where stem cells divide, and immune cells develop
Secondary Lymphoid Organs
Sites where most immune responses occur
Immune cells
:eukocytes - White blood cells
Secretions of immune cells
Cytokines
Bone Marrow
Blood cells are produced here:
B-cells and Immature T-cells
Site where B-cells Mature
Thymus
Located above the heart
Contains T-cells, scattered dendritic cells, epithelial cells and macrophages
Site where T cells mature
Atrophies after Maturity
Bursa of Fabricus
Part in chicken that gave B-cells their name
Place they were first discovered
Removing Thymus of chicken
T-cells won’t mature
Lymph Nodes
Scattered throughout the body
Filter microbes
Macrophages phagocytize microbes that enter lymph
Spleen
Largest lymphoid organ
removes microbes and old erythrocytes
Lymphoid Nodules
Tonsils
Peyer’s patches and MALT
Appendix
Immune cells travel in…
Blood and lymphatic system
How to WBC’s develop
Pluripotent hematopietic stem cell -> Lymphoid stem cell -> Lymphocyte
Lymphocytes
T-cells
B-cells
NK cells
T-cells
Cytotoxic T-cells CD8+
Helper T-cells CD4+
Regulatory T-cells CD4+
Granulocytes
Eosinophils
Basophils
Mast Cells
How does innate immune system work?
First line of defense of innate immunity
Physical barriers
Skin- water resistant
Additional Physical and Mechanical barriers
- tight junctions in epithlia
- mucus
- hair and cilia
Second line of defense of innate immunity
Cellular factors
Humoral factors
- Inflammation and fever
- Antimicrobial Substances
- Acute Phase reactants: C-reactive protein, complement, cytokines
Interferons
Chemical and Mirbobiological barriers
Secretions
- Sebum, lysosome, gastric juice
Normal Flora
Inflammation - Non-specific response to Tissue Damage
4 distinct signs and symptoms
-redness
- heat
- pain
- swelling
3 stages of inflammation
- Vasodilation
- Emigration of Phagocytes
- Tissue repair
Humoral Substances
Discourage Microbial Growth or spread of a pathogen
- Interferons
- Complement
- Iron binding Proteins
Type 1 interferon
Prevents viral replication
1) detects infection and produces type I inteferon proteins
2) other cells have receptors on their surface for these type I interferon proteins
3) when these receptors are activated the cells will produce antiviral proteins
4) Virus will not be allowed to replicate, cell machinery will not allow it
Complement
Large family of plasma proteins with multiple functions. 30 diff proteins participate in this cascade
ALTERNATIVE PATHWAY
Innate Immunity
Lead to activation of complement protein - C3B
C3B bind to surface of bacteria and via opsonization
Opsonization meaning
PREPARE FOR EATING
C3b as an Opsonin
Phagocyte has C3b receptors on surface
When infection the system will active it. It will then be released and stick to the bacteria so phagocytic cells can recognize them as foreign and ingest them
Iron-Binding Proteins - Transferrin
Binds up iron
Iron is kept away from the infection to make it harder for bacteria to divide
Immune system
Scattered and large
Connected by circulatory and lymphatic system
Lymphatic Organs
Primary
Secondary
Second Line of Defense - Cellular factors
Natural Killer (NK) Cells
Phagocytes
NK Cells
Class of lymphocytes
Target virus-infected cells and cancer cells
MHC class 1
If cells becomes infected or cancerous it stops expressing MHC 1
NK cell will then release perforins and granzymes to kill the infected body cells
Non-specific branch of immunity
Phagocytes
Engulf microbial invaders
Types of Phagocytes
Fixed-Tissue Macrophages - already in the tissues
Neutrophils - will be recruited to the sit of injury
Monocytes - macrophages and Dendritic Cells
Phagocytosis Steps
Microbe enters phagocyte through endocytosis
Phagosome forms around microbe
Lysosome brings in its eater things and puts them in the phagosome
Phagolysosome is formed
Microbe is destroyed
Release of end products into or out of cell
Macrophages vs Bacteria what have on surface
Macrophages: TLR
Bacteria: PAMPs
How does phagocyte recognize microbes?
PAMPs are recognized by immune system receptors called Pattern recognition Receptors (PRR) found on the surface of the macrophage: Toll-Like Receptors
Pathogen-Associated Molecular Patterns (PAMPs)
Lipopolysaccharide (LPS) of gram-negative bacteria
Peptidoglycan (PGN) of gram-positive bacteria
Vasodilation
Helps us get neutrophils to injury sites
Emigration of Phagocytes
Phagocytes move out
Chemotaxis
Chemokine/Chemoattractants
-Chemicals that attract phagocytes
Margination
Sticking to endothelial cells
Diapedesis
Phagocytes move across capillary wall
Emigration of phagocytes
Chemotaxis
Margination
Diapedesis
NET’s
Neutrophil Extracellular Traps
Made of processed chromatin bound to granular and selected cytoplasmic proteins which come from the lysed neutrophils
Do Neutrophils die in the process of killing bacteria?
Yes
Pus is produced In Neutrophil Attack. Why?
Pus is a mixture of dead bacteria and neutrophils
If neutrophils are not enough to fight bacteria what happens?
Antigen -Presenting Cell
Antigen-Presenting Cells
Immunogen - material that induces an immune response
Allergen
Ligand
Antigen
Antibody generator
Can be whole cells or a part of a cell
Can be non-microbial (Pollen, egg whites, Incompatible blood cells, transplanted tissues)
Epitope
Part of antigen that is recognized by the immune cells
Bridge between innate immunity and adaptive(specific) immunity
Via Antigen Presentation by Phagocytes
