Adaptive immunity Flashcards
What two adaptive immune responses result from clonal expression?
Kill/eliminate pathogens
Long-lived immunological memory
Lymphocyte activation occurs when what happens?
Specific antigen + co-stimulation
Pairing of accessory molecules stabilises interaction and provides co-stimulation to what?
T lymphocytes
What are the respones for a T cell antigen response (T-ind antigen)?
- Non-protein antigens
- Simple, repetitive antigens (often carbohydrates)
- PAMPs
- Induce mostly IgM antibody responses
- No memory B cells produced
T-d antigen is what?
T cell dependant antigen
T cell epitope is what?
Protein
B cell epitope is what?
Any molecule type
What is Interleukin 2 (IL-2)?
T cell mitogen and growth factor
What does the cytokine milieu determine?
CD4+ T cell differentiation and conversion into specific effector Th cell subtypes
What do Th1 cells do?
Activate infected macrophages
What do Tfh cells do?
B cell activation, proliferation and differentiation
Some pathogens can ascape phagolysosomal killing by macrophages. Name some examples
Salmonella
Listeria monocytogenes
Mycobacterium tuberculosis
What are Tdep antigens?
Short and long-lived plasma cells
What are Tind antigens|?
Short-lived plasma cells only
Antigen-activated CD8+ cells proliferate and differentiate into what?
Killer cells
What do CTLa (cytotoxic T lymphocytes do?
Migrate out of the lymph node and eneter sites of infection in order to kill infected host cells
How are CTLs selected killers?
- They only kill target cells expressing the correct peptide on MHC-Class I
- Also secrete pro-inflammatory cytokines
How are CTLs efficent killers?
They can recycle to kill multiple targets
What are the three components of CTL granules?
Perforin
Granzymes
Granulysin
What is perforin?
Polymerises to form a pore in the target membrane
Cylinderical structure
Lipophillic outside
Hydrophillic centre
What do Granzymes do?
- Serine proteases, at least 3 different types related to trypsin and chymotrypsin
- Induce apoptosis once in the target cell
What does granulysin do?
- Has anti-microbial properties
- Promotes apoptosis
What other way do CTLs kill?
Apoptotic pathway
Describe the return to homeostasis
Negative feedback signals reduce co-stimulation
-Often a consequence of prolonged T cell activation-Exhausted cells
Once the pathogen has been eliminated, tissue repair and wound healing is aided by what and how?
Macrophages which now witch from a pro-inflammatory state to an anti-inflammatory state
