16 Questions
What is the role of HLA proteins?
The role of HLA proteins is to present 'peptide antigens' to the immune system, enabling recognition of non-self antigens and development of immune responses.
Where are MHC-I proteins expressed?
MHC-I proteins are expressed ubiquitously on all nucleated cells in the body for the presentation of intracellular self/non-self antigens.
How are classical MHC-I proteins split?
Classical MHC-I proteins are split into HLA-A, HLA-B, and HLA-C subtypes.
What are the differences between classical and non-classical MHC-I molecules?
Non-classical MHC-I molecules are less polymorphic, expressed at lower levels, and have a more limited tissue distribution compared to classical MHC-I molecules.
To which class does HLA-G belong?
HLA-G belongs to the HLA nonclassical class I heavy chain paralogues.
How many isoforms of HLA-G are encoded by the same primary mRNA?
Seven different isoforms of HLA-G are encoded by the same primary mRNA through alternative splicing.
What are the four isoforms of HLA-G that are membrane-bound?
HLA-G1, HLA-G2, HLA-G3, HLA-G4
Which isoforms of HLA-G are released as soluble molecules?
HLA-G5, HLA-G6, HLA-G7
Name three types of cells that HLA-G can directly suppress the function of.
NK cells, T-cells, antigen presenting cells (APC)
What is the role of HLA-G at the maternal-fetal interface?
To avoid the lysis of semiallogeneic fetal tissue by maternal NK cells.
In transplanted patients, how may an increased expression of surface HLA-G and an augmented concentration of serum sHLA-G protect the transplanted organs?
From the rejection by the host’s immune system.
What is the pathological role of HLA-G expression on transformed cells?
It provides them with an immune escape mechanism, avoiding recognition and lysis by immune effectors such as NK cells and cytotoxic T lymphocytes.
What is the function of HLA-E in immune surveillance?
The presentation of self-peptides to NK cells, monitoring global HLA-I expression in the immune system.
What is the requirement for the surface expression of HLA-E?
Presence of peptides.
Which NK receptors does HLA-E bind to?
CD94NKG2A (inhibitory) and CD94-NKG2C (activating)
Which molecules does HLA-E bind peptides derived from?
Peptides derived from signal peptides of MHC class I molecules, namely HLA-A, B, C, G
Learn about the human leukocyte antigen (HLA) gene family and its role in presenting peptide antigens to the immune system, enabling recognition of non-self antigens and development of immune responses.
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