L6 - Adaptive Immunity 1 Flashcards
Name two strategic locations of antigen presenting cells in the body
Mucosa Associated Lymphoid Tissue (MALT) - skin (SALT)/mucous membranes (GALT)/tonsils or peters patches
Lymph nodes/spleen
Blood circulation (plasmacytoid and myeloid DC’s)
The hosts immune cells can recognise both extracellular and intracellular pathogens due to their variety of PRR’s. What type of pathogens and extracellular and what type are intracellular?
Extracellular - bacteria
Intracellular - viruses
What kind of Toll like receptors (PRR’s) recognise
a) gram positive bacteria
b) gram negative bacteria
c) viruses
a) 1 and 2
b) 4 and 5
c) 3, 7, 8 and 9
What is the difference between naive and effector T cells?
Naive T cells are not active because they have not yet come into contact with antigenic material
Effector T cells are already activated
Name the 4 types of APC and discuss where they are found
Dendritic cells - lymph nodes, mucous membranes, blood
Langerhans cells - skin
Macrophages - various tissue
B cells - lymphoid tissues
What chromosome are the human leukocyte antigens (HLA’s) found on?
Chromosome 6
What cells are the following proteins found on?
a) MHC class I
b) MHC class II
a) all nucleated cells
b) dendritic cells, macrophages and B cells
What key feature allows diversity of MHC molecules within the population
Codominant expression
Explanation - there are 6 types of type 1 and 6 types of type 2. Codominant expression means that we can have a huge diversity in the population
What feature of MHC genes increases the number of microbial antigens they can recognise
The fact that they are hugely polymorphic
WhICH MHC molecules present extracellular and which present intracellular microbes?
Extracellular - Type 2 (exogenous pathway)
Intracellular - type 1 (endogenous pathway)
Describe the endogenous pathway of processing intracellular microbes
1) virus/tumour enters cell and makes protein in the cytosol
2) peptide is targeted by proteasome
3) marked peptide transported to ER By TAP
proteins
4) formation of peptide-MHC class 1 molecule if correct match
5) presentation to CD8+ T cell
Describe the exogenous pathway of processing microbes
1) microbes captured by phagocytosis/ micropinocytosis
2) degradation into small peptides in endosome and bud off in vesicles
3) MHC class 2 containing vesicles fuse with peptide vesicles from endosome
4) if correct match they display to CD4+ T cells
What type of immunity is mediated by the exogenous pathway and what type by the endogenous pathway?
Exogenous - humoral
endogenous - cell mediated
Some patients are so called ‘elite controllers’, what is meant by this?
Can control viral replication. Viral load will be low in these patients even though they are vitally infected
Particular HLA alleles are associates with autoimmunity, mismatch between the alleles of the recipient and the donor are the major cause of rejection too. T/F?
T
