Intro to Immunology Flashcards
What are the most common sites of infection?
Skin and respiratory
What is the pathway for infection?
Exposure, adherence, invasion, colonization and growth, toxicity/invasiveness, tissue damage
What small molecules are secreted my skin and mucosa?
Defensins and cathelicidins
What do defensins do?
disrupt membranes of bacteria, fungi, protozoan parasites and viruses; intracellular toxic effects
What do cathelicidins do?
Disrupts membranes of bacteria; additional toxic effects intracellularly; kills cells
what part of the immune system to defensins and cathelicidins belong to?
Innate immune system
what is the charge and structure of cathelicidins?
Cationic, alpha-helical
How do defensins destroy bacteria?
wedging inside bacterial cell wall and ripping out pieces of the wall.
What is the structure of cytokines?
proteins/glycoproteins
What are chemokines?
large family of cytokines involved in attracting cells into inflamed tissues and play of role in leukocyte homing
What are interferons (IFNs)?
cytokines that important in limiting spread of viral infections
What are Interleukins (ILs)?
produced mainly by T cells (also macrophages, dendritic cells, epithelial cells), function by causing neighboring cells to divid and differentiate
What are colony stimulating factors (CSFs)?
involved in directing the division and differentiation of bone marrow stem cells and precursors of blood leukocytes. Controls how many and what kind of leukocyte is to be produced
What are tumor necrosis factors (TNFs)?
Particularly important in mediating inflammation and cytotoxic reactions
What are transforming growth factors (TGFs)?
important in regulating cell division and tissue repair
What is the pathway of the PLC pathway?
TCR –> PLCgamma1 –> calcineurin –> NFAT
What is cyclosporin used to treat? How does it work?
It’s an immunosuppressant that is used to treat both T cell mediated autoimmune disease and organ transplant rejection. Acts by blocking the fxn of calcineurin
How does the Ras/MAP pathway activate transcription?
Through AP-1
How does the PKC pathway activate transcription?
NF-kB
What is NF-kB transcription associated with?
proinflammatory and activation events
Describe the IL-1 family of cytokines?
Secreted early, stimulated in presence of foreign antigen, proinflammatory
Describe IL-1 signalling?
Works through TAK1 that then activates the MAPk and NF-kB pathways
What do receptors of hematopoietin (class 1) generally include?
Two types of proteins: immunoglobulin and fibronectin-like domain
What are the subfamilies of hematopoietin family cytokine receptors?
Gamma, Beta, gp130
What chains are involved in a strong hamtopoietin receptors?
gamma, beta and alpha
T/F: knockout of gp130 is embryonic lethal?
True
What cytokines interact with gp130 receptor?
IL-6 and IL-12
Where does gp130 get its specificity from?
ligand-specific chains in dimers or trimers that are couples with gp130
What are the two major types of interferon?
Type 1: IFN-alpha and IFN-beta, Type 2: IFN-gamma
What is the signaling cascade for interferons?
Cytokine binding –> activation of Jak –> Activation of STAT –> dimerization of STAT –> specific gene transcription
What does the TNF family activate for signaling?
Development, cell survival, cell death
Do TNF family members function as dimers or trimers?
Trimers
What produces TNF alpha? what is its role?
Activated macrophages (can also be produced by lymphocytes, fibroblasts and keratinocytes); proinflammatory
What produces TNF-beta? What is its role?
Activated lymphocytes; can activate neutrophils, endothelial cells, osteoclasts; can increase expression of MHC and adhesion molecules
T/F: innate immune system is non-inducible
true
what is the innate immune system mediated by?
phagocytosis
What do innate immune cells recognize on foreign antigens/bodies?
PAMPs
What are the pattern recognition receptors of the human immune system?
“Toll-like receptors”
What are TLRs?
transmembrane proteins that control innate immunity in invertebrates, as well as anterior/posterior differentiation; They bind to and are activated by PAMPs and DAMPs
What is included in PAMPs and DAMPs
PAMPs: LPS, ppg, lipopeptides, flagellin, bacterial DNA and viral dsRNA; DAMPs: intracellular prtns and prtn fragments from the extracellular matrix
What does stimulation of TLRs lead to?
signaling cascades that activate AP-1, NF-kB and interferion regulatory factors, resulting in production of IFNs, pro-inflammatory cytokines, and effector cytokines
What PAMPs does TLR4/4 recognize?
Outside: gram (-) bacteria, inside: viral proteins
What PAMPs does TLR2/1 recognize?
Bacteria, parasites
What PAMPs does TLR3/3 recognize?
Viral dsRNA
What PAMPs does TLR2/6 recognize?
gram (+) bacteria and fungi
What PAMPs does TLR7/7 recognize?
Viral ssRNA
What PAMPs does TLR5/5 recognize?
flagellated bacteria
What PAMPs does TLR 8/8 recognize?
viral ssRNA
What PAMPs does TLR11/11 recognize?
uropathogenic bacteria
What PAMPs does TLR9/9 recognize?
bacterial/viral DNA
In TLR signalling, what does My88-DEPENDENT pathway lead to?
production of inflammatory cytokines and one that leads to the production of IFN-α
in TLR signalling, what does My88-INdependent pathway lead to?
associated with the stimulation of IFN-β and the maturation of dendritic cells
What adaptor protein do nearly all TLRs bind? What about TLR3?
My88; TRIF
What does TLR signaling activate?
NF-kB which causes: expression of pro-inflammatory genes, increased phagocytosis and synthesis of ROS and nitrogen molecules; increased efficiency of antigen presentation
Are innate immune system cells part of lymphoid or myeloid lineage?
Myeloid lineage
What is required to induce CFU-GEMM stem cell to enter one of five pathways?
IL-3 and GM-CSF
What is eosinophil differentiation promoted by?
IL-5
What is the main role of mononuclear phagocytes?
remove particulate matter of “foreign” origin (microbes) or self origin (aged erythrocytes)
What do blood monocytes express and their functions?
CD14 (binds LPS), MHCII (binds Ab), CD11a and b (adhesion molecules), CD64 and CD32 (binds Fc receptors)
What is the function of dendritic cells?
antigen capture in one location and Ag presentation in another (from peripheral tissues move to lymph nodes to present to naive T-cells)
What attracts PMNs?
complement prtn fragements, factors of fibrinolytic and kinin systems, products of leukocytes and platelets, products of bactera
What do primary (azurophilic) granules of neutrophils carry?
acid hydrolases, myeloperoxidase, muramidase, antimicrobial proteins (defensins, seprocidins, cathlicidins
What do secondary granules of neutrophils carry?
lactoferrin and lysozyme
What proteins do neutrophils express?
CD11a, b and c (adhesion molecules), CD64, CD32 and CD16 (Fc receptors)
What are the primary roles of basophils?
Release of histamines in response to allergens, as well as fighting off flatworm parasites
What are mast cells responsible for?
Allergic responses
T/F: basophils are non-phagocytic?
True
What do eosinophils play a roll in?
defense against multicellular parasitic organisms, including worms
What WBCs play a role in B and T cell regulation?
neutrophils, basophils and eosinophils
