Lecture 12- 3rd line pt. 2 Flashcards
State the process for T-cell activation.
The APC must travel to the Lymphoid tissue to present to T-cells
Activation requires Primary and Secondary signal.
State the process for T-cell proliferation and differentiation.
Once activated, T-cells become:
- Make copies- 1) Cytotoxic T-cells 2)TH1 Helper cells 3)TH2 helper cells
- Make memory cells- inactive cells that hang around for another infection
- What are T-helper cells? 2. What are T-regulatory cells?
What proteins do they have for recognition?
- CD4; -Secretes Cytokines to signal/destroy/activate T-cyto and activates B-cells
- CD4; -controls inflammation, prevents autoimmunity, protects normal microbes
- What are Cytotoxic T-cells? 4. What are Memory T-cells?
What proteins do they have for recognition?
- CD8, MHC 1; -secretes preforins and granzymes that destroy infected host cells and cancer cells
- CD4, CD8; -saved for future infections, provides memory, specific for specific antigen
How does the cell eliminate pathogens? (2 ways)
- Elimination by cytotoxic T-cells
- Elimination by Helper T-cells -Recruit the other immune cells to destroy cell
How do Cytotoxic T-cells destroy infected cells?
Bind to MHC1 of host cell
- Secrete perforins that make holes in cell
- Release granzymes that breakdown cell
What do Memory T-cells do when there is no infection?
They stay in the lymphoid tissue so that upon re-infection by the same pathogen, they can act faster
What are the four stages of humoral response?
- Antigen presentation
- B-cell activation
- B-cell proliferation and differentiation
- Antigen elimination and memory
What cells are antigen presenting cells?
Does it need APC to activate?
B-cells;
No
How do these two routes activate B-cells:
- T-independent antigen activation
- T-dependent antigen activation
- .Antigen binds B-cell directly to activate
- for protection, must bind multiple times - requires helper T-cells to activate - antigen binds B-cell, endocytosed, processed -put on MHCII, presented to Helper T-cells
What happens during B-cell proliferation and differentiation?
- Only the B-cell that recognizes the antigen will proliferate.
- That B-cell will reproduce many clones rapidly
What do these cells do:
- Plasma cells
- Memory cells
- Sole purpose is to make antibodies
- remembers pathogen for faster response next time
What are the three methods that antibodies eliminate pathogens?
How?
- Directly neutralize the antigen
- Activate the complement system -cytolysis, opsonization, inflammation
- Increase immune cell phagocytosis -Precipitation, Agglutination, Opsonization
How to antibodies help? (BONACA)
Binding
Opsonization
Neutralization
Agglutination
Complement
Antitoxin
What is: 1. Binding 2. Opsonization
- attach to bacteria to prevent infection functions and reproduction
- coat bacteria so macrophages phagocytose better
