Case studies
Which virus is the causative agent of Mononucleosis?
Epstein-Barr Virus
Dendritic cells capture the pathogen and take it to the ________ to start an adaptive immune response.
Secondary lymphoid tissue.
Cells most likely to initiate an adaptive immune response.
What is a dendritic cell.
APC: dendritic cell, B-cell & macrophages
CR2 (CD-21), CD19 and CD81(TAPA-1)
What is the B-cell co-receptor?
Immunity gained from the mother for her baby and from anti-venom.
passive immunity
EBV infects theses cells
What are B-cells.
Why are most T-cells alpha beta?
To get gamma delta cells, both genes must rearrange before the Beta chain and then before the alpha (if the beta chain is rearranged)
The two signals needed to activate a T-cell.
What is TCR:MHC+peptide and CD28:B7 (on an APC)
Type of antigen that needs T-cell help to stimulate a B-cell.
What are thymus-dependent antigens?
Which disease has been eradicated via WHO by ring vaccination?
Smallpox
Rheumatoid Arthritis is a type of _____hypersensitivity reaction. Mediated by ________.
II, III & IV, Th1 Th17 cells.
Autoantibodies, (Type 11)
Immune complexes (type III)
CD4 Th1 & tTh17 cells
What is the Pre-T Cell receptor?
Beta chain +
Surrogate alpha chain: pTalpha
Why are cell adhesion molecules so important to the immune response?
Cell adhesion molecules are responsible for: 1. Movement of B & T cells from the blood to secondary lymph nodes. 2. Macrophages from the blood to enter sites of infection and injury. 3. Mantain contact with stromal cells during B & T cell development and APC's during activation.
Cells that contain antigen on their surface and select for high affintiy Ig on B cells after somatic hypermutation.
What are follicular dendritic cells?
“Antigen recognition by T cells is specific not for the antigen alone but for antigen associated with an MHC molecule.” Kuby, 2004
What is MHC restriction?
Describe a type IV hypersensitivity and give an example.
Type IV: Delayed Hypersensitivity which is mediated by CD4 TH1 cells and occasionally CD8 T cells.
Causes: Poison ivy, metals(nickel), and autoimmune responses such as MS and Rheumatoid arthritis (more complicated!)
Role of THFH cells?
Activation of B-cells
Maturation of antibody response. ( Afinity maturation, isotype switching and memory cells)
Activation of T-cells by co-stimulation causes the following cellular events:
Phosphorylation of ITAMS (Phosphorylation of Lck and activation of second messengers)
These activate transcription factors NFkappaB, NFAT, and AP-1, which turn on genes causing the cells to proliferate and release cytokines.
These B-cells have undergone somatic hypermutation and isotype switching and require cognate T cell help.
What are centrocytes?
T-cells bind to MHC and peptide in the thymus with moderate or strong binding.
What is positive selection?
If a person has a bone marrow transplant, what should medical personnel be concerned about regarding EBV?
Elimination of CD8 T-cells that keep EBV in check.
What causes T-cells to become anergic?
Lack of co-stimulation
The binding of Fas ligand to Fas induces apoptosis. Which cells kill via apoptosis and how does it differ from necrosis?
CD8 T cells aka cytotoxic T cells
NK cells and some CD4 Th1 cells
Apoptosis: neat and tidy-no peripheral damage. Necrosis: lysis of the cell, spilling the contents and causing damage to neighboring cells
Describe the shape and a function of IgM, IgG and IgA
IgM: Pentameric Low affinity, activates complement
IgG: High affinity for antigen, in serum and extracellular fluid, increases phagocytosis of pathogen
IgA: Dimer, secreted in mucus of lungs and GI tract for elimination of pathogen
What is a double-positive T-cell?
A T-cell that has both CD4 & CD8 co-receptors.
TCR is formed-no selection has begun.