Innate Immunity Flashcards
Have antigen presenting cells
Phagocytize anything that makes it through physical membrane
important actions of dendritic cells
What are these?
1. skin
2. Mucous membranes
3. Lungs
Physical barriers of innate immunity
What are defensive cells of innate immunity?
- Leukocytes
- Natural killer cells
These are?
1. Phagocytosis
2. Inflammation
3. Fever
4. Interferon
5. Natural killer cell
6. Complement
Process of innate immunity
Is a protective shield covered with keratin.
It has skin-associated lymphoid tissue that recognizes microbes that may slip past the physical barrier.
*langerhans- special dendritic cells
Innate host defense : skin
Barrier against invading pathogens
Coats surfaces and traps microbes
•lysozyme breaks down material
Mucosa-associated lymphoid tissue
Innate host defenses : mucous
Cilia in nasal cavity
Sneezing- forceful expulsion of air, to clear organisms from the respiratory tract
Organisms to alveoli are not easily expelled are met by phagocytic cells called alveolar macrophages
Innate host defense: lungs
•make up early WBC’s, use phagocytosis & primary target is bacteria
•release toxic products that kill microbes, they do not phagocytize
Neutrophils
Eosinophils/basophils
contain histamine & heparin granules, involved in inflammation, healing & allergies, and degranulate
Mast cells
identify and destroy infected/transformed host cells. Recognize cells that display MHC 1 molecules as healthy.
Natural killer cell
Found on all host cells
If absent, cells is destroyed when NK cells release perform and granzyme.
Major histocompatability 1 cells
Largest WBC’s
Circulate in the blood
Differentiate into macrophages &dendritic cells after leave the blood stream
Monocytes
Come from monocytes
Widely distributed through the body
Phagocytose
Present antigens on cell surface to T cells (active helper T cells)
Macrophages
Located in the spleen & lymph nodes
Phagocytose
Present small antigens on their cell surface to T cells
Different from macrophages in structure
Dendritic cells
Perforin
Pokes holes in the host cell
Enzyme that goes through the holes and disassembles the cell
Granzyme
Phagocytic cells have receptors that bind with the structures that are common in microbes but not host cells
Recognition of pathogen
Is the process of tagging cells for destruction by phagocytes. The death tags are antibodies that are recognizable by phagocytes.
Helps bacteria form capsules
Opsonization
- Bacteria binds to surface of cell, antibody or complement can aid
- Phagocyte extends and swallows organism
- Invagination of phagocyte membrane traps organism within phagosome
- Lysosome fuses & deposits enzymes into phagosome. Enzymes cut the bacteria into tiny pieces and destroy the organism
- Release of microbial disease: release of the particles alert other phagocytes that a pathogen is present. Phagocytes that are antigen presenting display MHC protein on outside of cell
Process of phagocytosis
Pathogens survive phagocytosis
Live in phagosome: coxiella
Escape from phagosome and gain access to cytoplasm
Prevent phagosome lysosome fusion- secrete proteins
Trigger apoptosis
Can be triggered when pathogens get past the physical barriers of innate immunity.
Provides a way for phagocytic cells to enter infected areas within tissues and initiate repair
Defense process: inflammation
Erythema, edema, pain, heat, and altered function.
Mast cells release histamine
Macrophages release cytokines to attract or activate more immune system cells
Defense process: inflammation
Type of cytokines- “SOS” signal
Produced by eukaryotic cells
Intercellular infection
Increase antiviral defenses
2 types
Defense process: interferons
Bind to specific receptors on uninfected host cells.
Induce cells to prepare for viral invasion
Type 1 interferons
Activate various white blood cells- macrophages, T cells & NK cells
Increase # of MHC antigens
Type 2 interferons
Normal body temperature is regulated by the hypothalamus.
Pyrogens- cause fever, signal the hypothalamus to shift body temperature upward.
Anything above 100.4
Crisis phase- vasodilation and sweating lower body temperature
Defense process : fever
Substance that causes fever
External- bacterial toxins
Internal- interferons, cytokines
Pyrogens
Series of 20 proteins in the blood that prevent blood infections and have a cascading event.
Defense process: complement
- Membrane attacks complexes- cause cytoplasmic leaks
- Attract WBCs
- Facilitate phagocytosis/opsonization
Complement: cascade event
