8. Classes of MHC moelcules
Class 1 MHC Class 2 MHC Class 3
MHC
9. Class 1 MHC molecule
-45 kDa α and 12kDa β2
microglobulin.
-α chain is a transmembrane
glycoprotein encoded by
polymorphic genes within the
A, B, and C regions of the
human HLA complex.
-peptide size 8-10 amino acids.
10. Class 2 MHC
molecule
-non identical glycoprotiens .
-33kDa α chain and 28kDa β
chain.
-α1, α2 and β1 and β2 domains
-peptide size 13-18 amino acids.
12. -Allelic variants of MHC are many.
-codominantly expressed.
-a group of linked MHC genes is generally inherited from
parents. – haplotypes
- Because of individual allelic differences in the peptide binding
clefts of the class I MHC molecules, different
individuals within a species will have the ability to bind
different
sets of viral peptides
-broad specificity.
13. MHC and disease susceptibility
HLA genes occur at a higher frequency-
Diseases associated with MHC-
14.
15. -Even a single amino acid difference in the peptide- binding groove can have a
profound impact on the spectrum of both self and foreign peptides that are
presented. Thus, an aspartic acid at amino acid residue position 57 in the HLA -
DQ β chain confers resistance, whereas an alanine, valine or serine at this
position confers susceptibility, to type 1 diabetes.
-Studies of knockout mice that lack
the gene for β2-microglobulin demonstrate
that MHC class I products on cell
surfaces are necessary for the maintenance
of normal iron metabolism. These
mice, which are unable to express any of
their class I molecules on the cell surfaces,
suffer from iron overload with disease
consequences similar to HH.
https://en.wikipedia.org/wiki/HLA-DQ
16. Disease susceptibility in cheetah
Loss of MHC
diversity – lead to
the emergence of
diseases in cheetah
population.
http://www.slideshare.net/JuliusManolong/cheetah-
genetic-diversity
17. -High level of MHC polymorphism that has been observed in various species may provide
the advantage of a broad range of antigen presenting MHC molecules.
-MHC diversity appears to protect a
species from a wide range of infectious diseases