robbins ch. 6 Flashcards
What are the major components of the innate immunity?
- epithelial barrier
- Phagocytic cells (mainly neutrophils and macrophages)
- dendritic cells
- NK cell
- plasma proteins (complement)
what antimicrobial molecule does the epithelium produce?
defensins
Natural killer cells provide early protection against what?
viruses and intracellular bacteria
What circulating proteins of innate immunity coat microbes and promote phagocytosis?
Mannose-binding lectin and C-reactive protein
cellular receptors that recognize pamps and damps are called what?
pattern recognition receptors
TLRs signal by a common pathway that culminates in the activation of what transcription factors?
NF-kappaB and Interferon regulatory factors (IRFs)
When NF-kappaB is activated by a TLR, what happens?
stimulates the synthesis and secretion of cytokines and expression of adhesion molecules, both of which are critical for recruitment and activation of leukocytes
When IRFs are activated by a TLR, what happens?
stimulates the production of antiviral cytokines, type I interferons.
What receptors are cytossolic receptors that recognize a wide variety of substances including products from necrotic cells, ion disturbances, and some microbial products?
Nod-like receptors (NLRs)
The NLRs that signal via the inflammasome actives what enzyme to cleave what?
caspase-1 to cleave and produce active IL-1
IL-1 is a mediator of inflammation that does what?
rectruits leukocytes and induces fever
Gain of function mutations in one of the NLRs results in what?
periodic fever syndromes called autoinflammatory syndromes
Autoinflammatory syndromes respond very well to treatments with what?
IL-1 antagonist
What receptors expressed on the plasma membrane of macrophages and dendritic cells detect fungal glycans and elicit inflammatory reactions to fungi?
C-type lectin receptors (CLRs)
What receptors are located in the cytosol of most cell types and detect nucleic acids of viruses that replicate in the cytoplasm of infected cells?
RIG-like receptors (RLRs)
What do RLRs stimulate the production of?
antiviral cytokines
What do G protein coupled receptos on neutrophils, macrophages, and most other types of leukocytes recognize?
short bacterial peptides containing N-formylmethionyl residues
What does recognition by the G protein receptor on neutrophils cause?
chemotactic responses
What receptors recognize microbial sugars and induce phagocytosis of the microbes?
mannose receptors
What are the 2 main mechanisms of innate immunity?
inflammation and antiviral defense
Type I interferon
Anti-viral
Mature lymphocytes that have not encountered the antigen for which they are specific are said to be what?
naive
After naive cells are activated by recognition of antigens and other signals, they differentiate into what 2 cells?
effector cells and memory cells
The enzyme in developing lymphocytes that mediates recombination of gene segments is the product of what genes?
RAG-1 and RAG-2 (recombination activating genes)