APPP 10 and 12: Body Defense System Flashcards
What are the 5 properties of the immune system?
- mobility
- replication
- specificity
- memory
- diversity
Properties of the Immune System
Mobility
systemic protection against localized insults through rapid cell migration to infected area
Properties of the Immune System
Replication
immune response is amplified through clonal expansion and signaling cascade
Properties of the Immune System
Specificity
prevent recognition of non-cross-reacting antigens and identify self vs. non-self
Properties of the Immune System
Memory
faster and stronger response to (similar) subsequent infection
Properties of the Immune System
Diversity
combinatorial library of antigen receptors to recognize innumerable pathogens
What are the primary lymphoid organs of the immune system?
- thymus
- bone marrow
What are the mucosal lymphatic tissues of the immune system?
- tonsils and adenoids
- appendix
- Peyer’s patches
What are the other organs of the immune system?
- lymph nodes
- spleen (gigantic lymph node)
What is the lymphatic system?
circulation system of lymphatic vessels
How does the immune system monitor all parts of the human body?
through the circulation system and the system of lymphatic vessels
- cells and fluids are exchanged between blood and lymphatic vessels, enabling the lymphatic system to monitor the body for invading microbes
Where are lymph nodes located?
- sit along the lymphatic vessels, with clusters in the neck, armpits, abdomen, and groin
What does each lymph node contain?
each node contains specialized compartments where immune cells congregate and encounter antigens
How many lymph nodes are in the human body?
500-600
What are the 4 functional areas of lymph nodes?
- cortex
- germinal centre
- para-cortex
- medulla
What does the cortex of lymph nodes do?
contains unactivated mature T cells
What does the germinal centre of lymph nodes do?
contains activated B cells → plasma cell development and antibody affinity maturation
What does the para-cortex of lymph nodes do?
contains a mix of unactivated and activated mature T cells
What does the medulla of lymph nodes do?
funnels to collect mature immune cells and antibodies for distribution to lymphatic/blood circulation
What is innate immunity?
first, rapid, short-term responses to a broad range of microbes – direct pathogen identification
- external defenses
- internal defenses
What are the external defenses of innate immunity?
- skin
- mucous membranes
- secretions
What are the internal defenses of innate immunity?
- phagocytic cells
- antimicrobial proteins
- inflammatory response
- natural killer cells
What is adaptive/acquired immunity?
slower responses to specific microbes (activated by, and responds to, innate immunity) – specialized and adaptable to a single type of invader, recognize invaders inside host cells, and able to recall encounters
- humoral response (antibodies)
- cell-mediated response (cytotoxic lymphocytes), with help from APC
Innate vs. Adaptive Immunity
Specificity
- innate: limited and fixed
- adaptive: extensive
Innate vs. Adaptive Immunity
Memory
- innate: none
- adaptive: yes
Innate vs. Adaptive Immunity
Time to Response
- innate: hours
- adaptive: days
Innate vs. Adaptive Immunity
Soluble Factors
- innate: lysozymes, complement, C-reactive protein, interferons, mannose-binding lectin, antimicrobial peptides
- adaptive: antibodies, cytokines
Innate vs. Adaptive Immunity
Cells
- innate: neutrophils, monocytes, macrophages, natural killer cells, eosinophils
- adaptive: B lymphocytes, T lymphocytes
Describe the specificity of innate immunity.
non-antigen specific
- uses pre-existing limited library of receptors (pattern recognition receptor) – ie. toll-like receptors (TLRs)
- recognition of highly conserved structures (pathogen-associated molecular patterns or PAMPs) – those essential to microorganism survival or pathogenicity (such as LPS and mannose)
- equal response to a range of organisms
What are the cellular mediators of innate immunity? (8)
blood:
- neutrophils
- eosinophils
- monocyte
- natural killer cells
- basophils
peripheral tissues:
- macrophage
- dendritic cells
- mast cells
What do neutrophils do?
ingest (phagocytotic) and destroy
What do eosinophils do?
release toxic molecules and destroy
What do monocytes do?
ingest, destroy, and antigen presentation
What do natural killer cells do?
kill cancer or viral-infected host cells
What do basophils do?
release first chemicals that start inflammation
What do macrophages do?
ingest, destroy, and antigen presentation
What do dendritic cells do?
ingest, recruit others, and antigen presentation
What do mast cells do?
release first chemicals that start inflammation
Tissue-Specific Types of Monocytes
Brain
microglial cells
Tissue-Specific Types of Monocytes
Lung
alveolar macrophages
Tissue-Specific Types of Monocytes
Liver
Kupffer cells
Tissue-Specific Types of Monocytes
Kidney
mesangial phagocytes
Tissue-Specific Types of Monocytes
Lymph Node
resident and recirculating macrophages
Tissue-Specific Types of Monocytes
Spleen
macrophages
Tissue-Specific Types of Monocytes
Blood
monocytes
Tissue-Specific Types of Monocytes
Bone Marrow
precursors
Tissue-Specific Types of Monocytes
Joint
synovial A cells