What cell type binds with MHC class I molecules?

MHC class I molecules are primarily recognized by CD8+ T cells, also known as cytotoxic T lymphocytes. These molecules are found on nearly all nucleated cells in the body and play a crucial role in presenting endogenous antigens, which are typically derived from proteins synthesized within the cell.

When a cell is infected with a virus or has undergone cancerous transformation, the proteins produced by these abnormal cells are processed and presented on MHC class I molecules. CD8+ T cells specifically bind to these complexes through their T cell receptors. This interaction is vital for the immune response, allowing CD8+ T cells to identify and destroy infected or malignant cells.

In contrast, CD4+ T cells bind MHC class II molecules, which present exogenous antigens typically from pathogens that have been ingested by antigen-presenting cells. B cells and plasma cells are primarily involved in antibody production and do not engage with MHC molecules in the same way as T cells. Thus, CD8+ T cells are specifically adapted to recognize MHC class I molecules, making them fundamental to the cellular immune response against intracellular pathogens.