Lecture 24 Flashcards
Thymus is:
a primary lymphoid organ. Largest at birth then shrinks with age. Sits at the top of the pericardium above the heart.
T lymphocytes express both:
CD4 and CD8 surface antigens
The MHC is:
group of genes that code for proteins found on the surfaces of cells that help the immune system recognize foreign substances. MHC proteins are found in all higher vertebrates. In human beings the complex is also called the human leukocyte antigen (HLA) system.
MHC refers to the genetic locus that regulates histocompatibility
CTL is:
Cytotoxic T cells react to you own cells when there is a change in MHC class 1 molecules i.e. when they express a neo antigen picked up from inside the cell. Killing non-self tumor cells.
Functional subset of CD4 helper T cells control the immune response:
Treg, Th1, Th2, Th17
Treg:
suppresses the immune response
Th1
promotes cell mediated immunity
Th2:
Promotes antibody mediated immunity
Th17
Promotes inflammation
MHC restriction: Viral immunity requires two antigens:
Self: antigen encoded by MHC
Non self: Antigen encoded by the virus
The T cell receptor is:
A membrane bound Ig-like molecule on T lymphocytes
H2 refers to:
The antigen on mouse cells
Humans Class 1:
A, B, C
Class 2:
DR, DP, DQ
HLA molecules are expressed on most cell and:
Present peptide antigens to T cells. They are highly polymorphic
CD4 and CD8 are:
Accessory molecules that physically associate with TcR.
CD4:
Helper T cells recognise antigens in MHC class II.
CD8:
Cytotoxic T cells that recognise antigens in MHC class I.
CD4 and CD8 have ___ that initiate T cell signalling through:
intracellular tyrosine kinases associated with their cytoplasmic tails, through phosphorylation
MHC class 1 peptide source, pathogen, T cell, effector function
Intracellular, Viruses, CD8, Cytotoxic
MHC class 2 peptide source, pathogen, T cell, effector function
extracellular, bacteria, CD4, Help
TcR does not undergoe affinity maturation. True or false?
True
TcR only recognises one antigen. T or F?
True
Congenic mice are:
Mice that are genetically identical excpet for the locus that controls tissue rejection. This means they only killed virally infected cells from their own strain, CTL is restricted by MHC.
The antigen binding surface of the TcR binds to:
the top of MHC, the peptide groove. Thus TcR has affinity towards the combination of MHC
Individual expression of MHC
Both maternal and paternal genes 2x3 Class 1 (A, B, C) and 2 x 3 class 2 (DR, DP, DQ). Co dominance for a total of 12 polymorphic molecules expressed on your cells.
2 major consequences of polymorphism:
1 Tissue transplantation is difficult except for in twins. This is because no two people share exactly the same MHC profile.
- MHC polymorphisms are strongly linked to many autoimmune diseases.
Cellular immunity is regulated by:
MHC, a set of highly polymorphic genes coding for a group of membrane molecules called HLA in humans.
