HLA Region Flashcards
what are polymorphic genes
different alleles that are present in the genes
what is co-dominant expression
both parental alleles of each mhc gene are expressed at the same point
what are the cell types for expressing mhc class II
dendritic cells, macrophages, b cells
what are the cell types for expressing mhc class I
all nucleated cells
why is it important for mhc class I to be polymorphic
becauase mhc class I is a part of the endogenous pathway to present every endogenous antigen that’s possible
for hla class I why is it important you have three different genes and what are they
its important to have three different genes because all three can present antigens and the gives more potential for a more functional immune system a HLA-A HLA-B HLA-C
what causes variability in the HLA genes and why is this good
there are a high number of alleles in each gene just in case one went wrong you have another to back it up
what are common alleles
they are alleles that when expressed have the same binding pocket and tend to pick up the same peptides which is the commonality between them
what are non classical hla genes are what are they useful for
HLA-E HLA-F HLA-G non classical genes are less polymorphic
what are classical hla genes and what are they useful for
they are involved in the presentation of peptides to CD8+ cells
what are the three main ways to protect foetus in the maternal-foetal interface
cytokine shift, influence of female sex hormones and unique hla expressions by trophoblasts
functions of hla e
hla resides on the surface of placental cells and trophoblasts, they intract with NK cells to see if anything needs to be broken down
what are trophoblasts
are the outer layer of cells forom the blastocyst are it provides nutrients to cell
functions of hla g
activates maternal t-regs and inhibits maternal natural killer cells to cause cell death
what genes play a role when a cell becomes stressed and what do they do
MICA and MICB genes and they activate natural killer cells
what are the subtypes of classical class II molecules and their role
HLA -DR
HLA- DQ
HLA -DP
they make their own mhc and they are involved on presenting exogenous antigen for recognition by CD4 t cells
why is important to have multiple HLA D genes
if one fails or is comprised there are other genes that are back ups
what does it mean when HLA-DRB it made to non-polymorphic alpha chains
alpha chains are identical
are the beta chains in HLA_DRB non-polymorphic or polymorphic
they are VERY polymorphic to make up the fact the alpha are not
what does oilogomorphic mean
a little bit of polymorphism but not much
how are HLA class I or class II expressed
they are expressed in a co-dominant matter
what is linkage disequilibrium
the non random association of alleles at different loci in a given population with a higher or lower chance of being associated whereas normally it would be inherited randomly
what are haplotypes
group of genes inherited together from single parent
