How many MHC molecules present in a one cell ? ?

The exact number of Major Histocompatibility Complex (MHC) molecules present in a cell can vary depending on the type of cell, species, and other factors. MHC molecules are proteins found on the surface of cells that play a crucial role in the immune system by presenting antigens to T cells, which are a type of immune cell. MHC molecules are classified into two main types: MHC class I and MHC class II. MHC class I molecules are typically found on almost all nucleated cells in the body, and they present antigens derived from intracellular pathogens, such as viruses, to cytotoxic T cells. Each MHC class I molecule typically presents one antigenic peptide at a time. The number of MHC class I molecules on a cell's surface can vary, but estimates suggest that there may be thousands of MHC class I molecules on a single cell. MHC class II molecules, on the other hand, are typically found on specialized antigen-presenting cells (APCs), such as macrophages, dendritic cells, and B cells. MHC class II molecules present antigens derived from extracellular pathogens to helper T cells. Similar to MHC class I molecules, the number of MHC class II molecules on a cell's surface can also vary, but estimates suggest that there may be hundreds to thousands of MHC class II molecules on a single cell. It's important to note that the number of MHC molecules on a cell's surface can change in response to various factors, such as the presence of pathogens, cytokines, or other environmental cues. The precise number of MHC molecules on a cell can be challenging to determine accurately and may vary depending on the specific context.