What are the two main classes of Major Histocompatibility Complex (MHC) molecules, and how do they differ in terms of the cells they are found on, the type of antigens they present, and the T cells that recognize them?
The two main classes of MHC molecules are MHC class I and MHC class II. MHC class I molecules are found on all nucleated host cells and present endogenous antigens (from inside the cell, such as viral antigens) to cytotoxic T cells (CD8 cells). MHC class II molecules are found only on antigen-presenting cells (APCs) like dendritic cells, macrophages, and B cells, and present exogenous antigens (from outside the cell) to helper T cells (CD4 cells).
What does MHC stand for and what is its main function?
MHC stands for Major Histocompatibility Complex, and its main function is to present antigens on the surface of host cells to T cells to help generate an immune response.
Where are MHC class I molecules found in the body?
MHC class I molecules are found on all nucleated host cells.
What type of antigens do MHC class I molecules present?
MHC class I molecules present endogenous antigens, which originate from inside the cell, such as viral antigens.
Which type of T cell recognizes antigens presented by MHC class I molecules?
Cytotoxic T cells (CD8 cells) recognize antigens presented by MHC class I molecules.
On which cells are MHC class II molecules found?
MHC class II molecules are found only on antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells.
What type of antigens do MHC class II molecules present?
MHC class II molecules present exogenous antigens, which originate from outside the host cell.
Which type of T cell recognizes antigens presented by MHC class II molecules?
Helper T cells (CD4 cells) recognize antigens presented by MHC class II molecules.
What role do CD markers play in T cell and MHC interactions?
CD markers guide T cells to interact with the correct MHC class: CD8 with MHC I and CD4 with MHC II.
Can a cell have both MHC class I and class II molecules, and if so, which cells?
Yes, antigen-presenting cells (APCs) like dendritic cells, macrophages, and B cells have both MHC class I and class II molecules.