Adaptive Immunity Flashcards
1
Q
What are the 4 main characteristics of adaptive immunity?
A
- RECOGNITION - Immune cells’ ability to recognise own cells versus pathogen
- Lymphocytes tailored to combat specific antigens
- DIVERSITY - Many B and T cells that recognise a huge amount of antigens
- Immunological memory
2
Q
What are the types of adaptive immune cells?
A
- B cells - humoral immunity - defense via antibody production
- T cells - cellular immunity - CD4+ helper cellls/ CD8+ cytotoxic cells/memory cells
3
Q
Describe how the location of B and T cells change
A
- Both cells produced in bone marrow
- B cells mature in bone marrow/ T cells mature in thymus
- Circulate through blood and secondary lymphoid tissues(where they become active)
4
Q
Compare and contrast the TCR and BCR.
A
- TCR - membrane bound αβ heterodimer
- BCR - membrane bound antibody
- Both have ITAMs - activate the cells
5
Q
What occurs in positive and negative selection?
A
- POSITIVE - T cell in thymus binds moderately to MHC and survives
- NEGATIVE - T cell binds strongly - results in death of cell
6
Q
Describe T helper and regulatory T cells.
A
- Both have CD4 surface molecules
- Both are activated by APCs presenting antigens associated with MHC II
- HELPER - orchestrate humoral/cellular immunity - activate macrophages/NK cells
- REGULATORY - Prevention of autoimmune responses
7
Q
Describe cytotoxic T cells
A
- Have CD8 surface molecules
- Activated by APCs or infected nucleated cells presenting antigens linked to MHC II
- Destroys infected cells
8
Q
Give three types of APCs
A
DENDRITIC
MACROPHAGES
B CELLS
9
Q
How are cytotoxic cells activated?
A
- Dendritic cells process viral proteins
- Presentation of endogenous antigens with class I MHC on surface
- Activation occurs
10
Q
What is required for T cell activation?
A
Antigen presentation with MHC II
11
Q
What is antigen processing?
A
- Enzymatic process of degrading proteins through proteases into antigenic peptides.
- Requires energy (ATP) , movement of endocytic vesicles.
12
Q
Describe MHC II antigen processing.
A
- Peptide production in phagolysosome
- Peptide binding by MHC
- MHC presents peptide at cell surface
13
Q
Describe MHC Class I antigen processing.
A
- Antigen processing to peptide in proteasome
- Peptide transported to ER
- Peptide binding by MHC
- MHC presents peptides at cell surface
14
Q
Describe Class II MHC mediated T cell activation.
A
- Maturation in thymus
- Forms CD4 cell with TCR
- Activation through binding to Class II MHC protein displaying antigen
- Mature to form effector cells - form memory/helper/regulatory T cells
15
Q
Describe Class I MHC mediated T cell activation.
A
- Maturation in thymus
- Forms CD8 cell with TCR
- Activation by binding to Class I MHC protein displaying antigen
- Form memory and cytotoxic cells
