Week 17: (A) Major Histocompatibility Complex Flashcards
What do we need to happen to have a specific immune response?
lymphocytes specific to the invading pathogen to be stimulated
What do the specific immune cells in primary response divide to make?
effector cells
Memory cell pool
What do the memory cell pool cells divide to make in a secondary response?
memory cell pool
effector cells
(both larger pools)
How do B cells recognise antigens?
The B cell has antigens specific to the immunoglobulin
A type of immunoglobulin anchored in the surface B cell called B cell receptor (BCR).
Does the antigen need to be processed to be recognised by the specific BCR?
NO, binds to native antigen pathogens
How do T cells recognise antigens?
TCR (T cell receptor)
Does the antigen need to be processed to be recognised by the TCR?
YES, recognise parts of antigens that are processed and depressed on host cell surfaces
What type of antigen can the TCR recognise?
1) Antigens derived from pathogens that replicate within a host cell, viruses or intracellular bacteria
2) Antigens derived from pathogens or products that have been endocytose from the extracellular fluid
How do host cells display antigens on their surface?
T cells
cells display their surface peptide fragments derived from pathogens proteins.
How does the host cells display pathogen derived peptides on their surface?
relies on specialised glycoproteins known as Major Histocompatibility compile (MHC) molecules
What are the 2 families of MHC molecule?
Class 1; HLA-A, HLA-B & HLA-C
Class 2; HLA-DP, HLA-DQ & HLA-DR
When are class 1 MHCs expressed?
on all nucleated cells including leucocytes
When are class 2 MHCs expressed?
only on leucocytes which present antigen to T cells
i.e. antigen presenting cells
What does is mean that a MHC is polymorphic?
many versions of them
How many forms of each MHC?
only 2 forms from each parent. co-dominantly
e.g. HML-A (23 & &)
