Lecture 4 - MHC and Antigen recognition by T cells Flashcards
What is the growth cycle of T-cells?
- Originate in the bone marrow
- Differentiate to mature T-cells in the thymus
- Migrate to the lymphoid tissues
What is the growth cycle of B-cells?
- Originate in the bone marrow
- Differentiate to B-cells in the bone marrow
- Migrate to the lymphoid tissues
What were the adverse effects that Thymectomised mice suffered? [3]
- Susceptibility to viral infection
- Reduced lymphocytes
- Immuniodeficiency
True or False? As we age our Thymus gets bigger and works better.
False. It gets smaller and declines in function.
How do B-cells recognise antigens?
- Express cell surface IgM and IgD.
- Gains specificity by varying the variable regions
Describe the structure of a T-cell receptor.
- Contains an alpha and beta chain
- The alpha and beta chains are held together by di-sulphide bonds
- Has a constant and variable region
What is the role of CD3 on the T-cell receptor?
Interacts with the receptor to mediate intracellular singalling
How do T-cell receptors recognise antigens?
The antigen has to be processed and presented to them via a Major Histocompatibility Complex (MHC)
What is a MHC?
A collection of genes within a long continuous stretch of DNA.
What are the classes of MHC? [3]
- MHC class I
- MHC class II
- MHC class III
Where are MHC I expressed?
Glycoproteins expressed on all nucleated cells
What is the role of class I MHC?
Involved in T-cell recognition of antigen (Tc)
What part of the loci codes for MHC I?
A, B, and C regions
What is the role of MHC II?
Involved in T-cell recognition of antigen (Th)
Where is MHC II expressed?
Glycoproteins on antigen presenting cells
