3/30/17 TEST #3 B cell-mediated immunity GERMAN Flashcards
If you can not form T cell immune synapses, which of the following immune functions would you anticipate to be disrupted? A) T cell activation B) B cell activation C) CD8 T cell targeting D) All of the above E) None of the above
- D) All of the above
- Because the B cell is activated by TFH cells and the others are T cells that need immune synapses to be activated
After you have positive selection with B cells what are the next three steps of B cells?
- Search for infection
- Finding infection
- Attacking infection
Where in the body to B cells find infection and become activated?
-Secondary lymphoid tissues
What two types of effector cells do B cells become?
- Memory Cells
- Plasma cells
B cells mature within and migrate through what types of tissues?
-Secondary lymphoid tissues
B cells are presented antigen where?
-In lymph nodes
What do the follicular dendritic cells and the macrophages do with intact antigens?
-Capture them and present them in the B cell areas in the lymphoid tissue
What does activation of B cells drive?
-Clonal expansion
-Class switching
-Somatic hypermutation
(These processes require T cells)
What presents antigen to B cells coming into the lymphoid tissue?
- Macrophages
- Follicular Dendritic cells
What are stromal cells involved in B cell development and activation?
-Follicular dendritic cells
Do follicular dendritic cells have phagocytic activity?
-No
How do follicular dendritic cells accumulate antigens?
-Via complement receptors
What are the two antigen types that can activate B cells?
- Thymus-dependent antigen
- Thymus-independent antigen
What three things are involved with thymus-dependent antigens to activate B cells?
- Protein
- Protein associated antigen
- TFH cell interaction required
What two things are involved with thymus-independent antigen to activate B cells?
- PRR-detected antigen
- Complement-bound antigen
What are three signals needed for B cell activation?
- Antibody Crosslinking
- Co-receptor signaling
- Cytokines
What does antibody crosslinking do for B cells?
-Activation
What does co-receptor signaling do for B cells?
-Survival and proliferation
What do cytokines do for B cells in activation?
- Differentiation
- Class switching
- SHM (Somatic Hypermutation)
What does crosslinking of B cells involve?
- B cell receptor
- Antigen
How does the B cell know that the antibody is bound to an antigen?
- You get clustering and aggregation
- Iga and Igbeta signaling
- ITAM phosphorylation and signal recruitment
How does the B cell ensure that the antigen is pathogenic?
- Co-receptors
What prevents anergy in B cells?
-Co-receptor signaling
What allows the B cell to distinguish between foreign or self antigen?
-Co-receptor signaling
If a B cell binds a pathogen but doesn’t bind a co-receptor signal what type of pathogen is it?
-Self antigen
What initiates clonal expansion for B cells?
-Co-receptor signaling
What are B cell co-receptor complex molecules?
- CR2
- CD19
- CD81
- Complement
What cells are the most common source of cytokines during B cell activation?
-TFH
What provides signals in the absence of T cell-mediated activation?
-Local cytokines
What does somatic hypermutation due for antibodies?
-Increase antibody speficficity
Once B cells are differentiated what do they become?
- Plasma cells
- Memory B cells