Innate Immunity

Question 1

what are the cells included in the innate immune system?

Answer 1

epithelial cells
phagocytes
dendritic cells
natural killer cells
complement (proteins)

Question 2

what are the two strategies for recognition for the innate immune system and explain them?

Answer 2

1.microbial non-self: recognizes structures unique to microorganism and not produced by the host

2. missing self: recognition of molecular structure (MHC) expressed only on normal and uninfected cells of the host

Question 3

which recognition strategy is important in the activation of natural killer cells?

Answer 3

missing self

Question 4

what are examples of microbial non-self molecules?

Answer 4

• pathogen associated molecular patterns (PAMPs)
• conserved molecular structure
• invariant among pathogens of a given class
• products of metabolic pathways
• molecules that essential for microbial survival
• molecules produced by microbes

Question 5

what do damaged or dying cells release that actives the innate immune system?

Answer 5

endogenous danger molecules also called damage associated molecular patterns (DAMPS)

Question 6

what is an example of a pathogen-associated molecular pattern molcules (PAMPS)?

Answer 6

lipopolysaccharide of gram negative bacteria or lipoteichoic acid of gram positive bacteria

Question 7

what are the types of pattern recognition receptors for PAMPs molecules?

Answer 7

• intracellular (NOD-like receptors)
• surface (toll-like receptors)
• secreted

Question 8

explain how toll-like receptors work (TLR)?

Answer 8

• transmembrane proteins that recognize more than one ligand that may be structurally unrelated from each other

Question 9

which toll like receptor binds LPS (G-) and lipoteichoic acic (G+)?

Answer 9

TLR-4

Question 10

what does the binding of PAMPS to PRR activate?

Answer 10

immune response and links innate to adaptive immunity by leading to the production of molecules that control adaptive immunity

Question 11

what are the main purposes of macrophages?

Answer 11

• increased differentiation into dendritic cells
• presentation of antigens to T lymphocytes
• production of cytokines and chemokines

Question 12

what do the innate lymphoid cells detect?

Answer 12

changes in the microenvironment through receptors for cytokines

Question 13

what do natural killer cells do and how?

Answer 13

• tumor surveillance i.e cytotoxic killing of virus infected or damaged cells
• they have receptors for IgG

Question 14

what is (ADCC) antibody-dependent cell cytotoxicity?

Answer 14

antibodies bring NK cells containing Fc receptor for IgG in contact with target cells

Question 15

how do natural killer cells recognize a target?

Answer 15

• activation signaling turns on cells through the phosphorylation of protein tyrosine kinases of the immunoreceptor tyrosine based activation motifs (ITA-MS)

Question 16

what happens when MHC class 1 receptors are bound?

Answer 16

• the cell is normal and not virus infected
• signaling of immunoreceptor tyrosine-based inhibitory motifs and the recruitment of phosphatases

Question 17

what is the erythrocyte sedimentation rate (ESR)?

Answer 17

a blood test for the current presence of inflammation

Question 18

what is C- Reactive Protein?

Answer 18

the liver produces it upon activation by macrophages and binds to lysophosphatidylcholine expressed on surface of dead or dying cells

Question 19

what is the main purpose of dendritic cells?

Answer 19

present the antigens to T cells and provide signals that stimulate the proliferation and differentiation of the lymphocytes

Question 20

what are dendritic cells derived from?

Answer 20

hematopoietic progenitor cell derived

Question 21

what are the two types of dendritic cells in the blood?

Answer 21

• conventional dendritic cell: activated by PAMPs
• plasmacytoid dendritic cell: activated by viral infection by recognizing nucleic acids of viruses (produces type 1 interferons)