Immuno

Question 1

Cytokines

Answer 1

Ones that enhance NK cells: IL-2, IL-12, IFN-a, IFN-B

Induce Th1 - IL-12
- Th 1 secretes IL-2, IFN-y; IFN-y inhibits Th2
Induce Th2 - Il-4
- Th2 secretes IL-5 (IgA), IL-4 (IgE), IL-2, IL-10; IL-10 inhibits Th1
Induce Th17 - TGF-B, IL-6

IL1 - fever, endothelium expression of adhesion molecules, chemokines to recruits WBCs
IL2 - stimulates growth of helper, cytotoxic and regulatory T cells and NK cells
IL3 - bone marrow stem cell growth/differentiation (IL-B for bone marrow)
IL4 - differentation into Th2, B cell growth, class swtching to IgE and IgG
IL5 - differentiation of B cells, class switching to IgA, eosinophil differentiation
IL6 - fever and acute-phase reactant production (by liver)
IL8 - neutrophil chemotaxis
IL10 - decreases MHCII and Th1 cytokines, inhibits activated macrophages/dendritic cells, secreted by Tregs
IL12 - T cells into Th1, activates NK cells
TNFa - mediates septic shock and induces systemic inflammatory response, activates endothelium, WBC recruitment, vascular leak; cachexia in malignancy
IFNy - secreted by Th1 cells; stimulates macrophages to kill phagocytosed pathogens, activates NK cells to kill virus infected cells, increases MHC expression and antigen presentation
TGFB - attenuates immune response similar to IL-10

IFNa and IFNB - interfere with viruses

• synthesized by virus infected cells, help local uninfected cells by helping to selectively degrade virla nucleic acid and protein; results in apoptosis
• suppress viral replication and induce apoptosis in infected cells
• activates RNAse L (degrades viral and cellular mRNA) and protein kinase R (inhibits translocation)

Question 2

CD markers

Answer 2

CD16 - Fc receptor; on NK cells, ADCC binds Fc region of bound Ig
Tregs - CD3, CD4, CD25, FOXP3
CD28 - co-stim on T cell, binds B7 AKA CD80 on APC
CD40 - B cell co-stim, binds CD40L on T-cell
CD3 - associated with TCR for signal transduction
CD117 - GIST, mast cells
CD99 - Ewing’s sarcoma
B cells - CD19, CD20, CD21
CD21 - receptor for EBV
Macrophages - CD14, CD40
NK cells - CD16 (binds Fc of IgG for ADCC), CD56
CD34 - hematopoeitic stem cell marker
CD18 - subunit of integrins, important in leukocyte adhesion deficiency
CD14 - a TLR, recognizes LPS on gram neg bacteria

Question 3

Complement

Answer 3

MAC defends against gram neg
Classical pathway
- IgG or IgM mediated
- C1, to C4b2b convertase
Alternative pathway
- microbial surfaces trigger this
- makes C3bBb convertase
Lectin pathway
- Mannose binding lectin, on microbial surface
- start with C1 like complex, make C4b2b convertase
All can then create C3b
- can continue on to C5 convertase, end up going through C5b-C9 ending in MAC

Question 4

Lactoferrin

Answer 4

Inhibits microbial growth via iron chelation