antigen presentation and MHC Flashcards
what are MHC protiens
found on the surface of nuceated cells called Ir or immune response genes because they control the protiens antigens to which an individual can respond, in humans they are called HLA
what is MHC haplotype and Polygenic
haplotype is the totle set of MHC genes on each chromosone one haplotype from each parent, and polygenic means multiple different genes within each individual so the d region and the B C and A region
what makes up class one MCH and what makes class 2
Class one is the B C A region and Class two MCH is the D region
How are MCH genes ploymorphic and why
they have a high amount of variability in humans allows us to have unique immunities naturally and B has 1431 different variants of the gene in the population.
know how variations in individuals arise and how this effects transplants
each person get three class one and three class 2 from each parent and then they can still pair up and make even more combination this is why transplants are so difficult because so many combiniation can occure.
what is the role MCH proteins
t lymphocytes will only respond to antigens when they are presented in conjunction with MCH proteins
know how certain HLA alleles are found more often with certain diseases
HLA DR2 found in narcolepsy in 100 percent of patients with and 22 without, and ankylosing spondylitis inflammation of vertebrae and spinal deformities have HLA-B27 in 90 percent with and only 9 percent without disease.
how is paternity testing done
HLA typing of the mother child and alleged father, can exclude father but not completely include.
where are class one MCH protiens found and what happends when you dont have them
everywhere except the red blood cells. Infection of RBC by plasmodium goes undetected by T lymphocytes
what are the four parts of the type 1 MHC proteins
Alpha 1 and 2 are peptide binding and a 3 is trans-membrane portion whereas the Beta 2 is non covalently linked to the unit in the cytoplasmic but still essential to function
what does the peptide binding region of class one MCH
hold forieng particle uses the CD8 receptor can only hold peptides 9-11 AA long because ends are pinched inward
tell me about the peptide binding region of class 2 MCH
recognized by CD4 receptors open ends so it can hold larger AA up to 10-30 long
what are the four parts of of the MCH 2
two non covelantly liked chains one with Beta 1 receptor and b 2 and the other with Alpha 1 recept and a 2
where can you fin class 2 MCH proteins
only on antigen presenting cells , dendritic cells, macrophages, and b lymphocytesand thymic empithial cells.
why are MCH important in recognition by T lmphocytes
t lymphocytes can only recognize denature protien antigens so MCH has to process them and then serve them up so they can be recognized.
what are the cells that are professional antigen presenting cells, and what one is the most potent
Macrophages dendritic cells and b lymphocytes and dendritic are the most potent
what are the characteristics of dendritic cells
long lived born in the bone marrow live in tissue and sample the environment looking for antigens to present to t cells present in nearly all organs
how do apc and t lymphocytes activate each other
APC activate t lymphocytes by presenting the antigen then t lymphocytes release interferon gamma that upregulates the class 2 MCH proteins on the surface of the APC resulting in more cells to present antigen to T lymphocytes
what does a dendritic cell do when it finds an antigen
immature cells take up antigen become activated and migrate to nearest lymphodi tissue where they mature and present antigen to T helper lymphocytes.
what happends in exogenous antigen processing
the external antigen is phagocised and mixed with a capped MHC 2 receptor and then the cap leaves and they travel to the cell surface together
what happends in endogenous antigen processing
internal viral proteins mix with MHC 1 in the ER and then transported to the cell surface
what transports the degraded protiens to the ER for MHC 1 binding
Tap Protiens
what type of antigen is most effect in virus and turmor cells and what type against extracellular pathogens
extraceullular is the MHC 2 and the viral and tumor is the MHC type 1
