Lecture 8 Flashcards
What are the roles of MHC proteins
T cell activation, graft rejection, antigen presentation to t cells, development of t cell repertoire/ tolerance in the thymus, self/non-self recognition, association with certain autoimmune diseases
What can the protein CD4 do
Its able to interact with MHC2 through invariant regions. Also able to interact with MHC1 protiens
What do CD4 and CD8 contain
Immunoglobulin like domains interacting with one another. This contributes to signalling and enhances the interaction between the two cells
What does AIRE (autoimmune regulator) allow
Allows the expression of non-thymus proteins.
Where are MHC proteins expressed
On chromosome 6 and are very large gene complexes
What are the 3 gene loci in MHC 1 genes
HLA A, B and C. Each of these encode for a polymorphic alpha chain.
What do the 3 loci in MHC 2 genes code for
An alpha chain and a beta chain called HLA dp, dq and dr
What are the consequences of MHC polymorphism
- Causes graft rejection
- The variability of MHC molecules is small compared to that of TCR
T cell responses are determined by an individuals MHC type each MHC allele can bind a restricted range of related peptides.
Structure of IgG
Variable regions are VI and VH. Constant regions are CL.
IgG has a long hinge region. Occurs as a monomer. It’s the main antibody tissue used in blood
What IgG molecules are the most biologically active
IgG1 and IgG3. - Have the longest hinge
How does IgG activate complement
Via the classical pathway
Structure of IgM
it’s a pentamer in plasma and is facilitated by an extra peptide called J chain. IgM doesn’t have a hinge region but an extra pair of domains and tail pieces.
