Major Histocompatibility Complex is a tight cluster of linked___________
A.
Carbohydrates
B.
Proteins
C.
Genes
D.
Lipid molecules
Answer: Option C
Explanation:
MHC is polygenic in nature, i.e. several genes control the expression of the MHC molecule. These are cell surface proteins which are present with peptide on antigen presenting cells.
Genes for MHC are located on the short arm of chromosome 6 in humans. In human, it is also known as human leukocyte antigens (HLA). MHC is glycoproteins which are expressed on all nucleated cells.
Which of the following polypeptide is important for the expression of MHC I on the cell membrane?
A.
Interferons
B.
β2-microglobin
C.
Lymphokines
D.
Interleukins
Answer: Option B
Explanation:
β<sub>2</sub>-microglobin is encoded by chromosome 15, it is always attached to α3 subunit of MHC I molecules through non-covalent interactions. It does not have a tail.
Which of these are non-professional antigen presenting cells?
A.
Macrophages
B.
Dendritic cells
C.
Fibroblast
D.
B lymphocytes
Answer: Option C
Explanation:
Antigen presenting cells (APC) is of two types i.e. professional and nonprofessional antigen presenting cells. Professional antigen presenting cells are Blymphocytes, dendritic cells, and macrophages while non-professional APCs are fibroblast, epithelial cells, glial cells etc.
Name the cell which receives antigen presented by MHC molecule.
A.
Nk cells
B.
B-cells
C.
T-cells
D.
Macrophages
Answer: Option C
Explanation:
MHC molecules present processed antigen to T-cells as T-cell receptor does not recognize free antigen, it will recognize only those antigens which are bound to MHC molecules.