MHC class I H2-Kb heavy chain (H2-Kb)

The MHC class I H2-Kb heavy chain is a classical major histocompatibility complex class I molecule expressed on nearly all nucleated cells in mice, forming a heterodimer with beta-2-microglobulin to present 8-10 residue peptides derived from intracellular proteins in a groove formed by alpha1 and alpha2 domains flanked by alpha-helices. This presentation enables recognition by CD8+ cytotoxic T lymphocytes via their T cell receptors, triggering targeted cell killing to eliminate virus-infected or malignant cells, thus mediating adaptive cellular immunity against intracellular pathogens like viruses and certain bacteria. H2-Kb also interacts with CD8 to enhance T cell signaling and serves as an inhibitory ligand for natural killer cells to prevent lysis of healthy self-cells. Beyond immunity, H2-Kb negatively regulates proliferation of neural stem and progenitor cells by modulating growth factor signaling and cell cycle progression, independent of immune functions, influencing adult hippocampal neurogenesis. While not a direct small-molecule drug target, its role in antigen presentation makes it central to immunotherapies like peptide vaccines or checkpoint inhibitors in cancer and infectious diseases, though genetic deficiency reveals risks like impaired CD8+ T cell memory and NK cell calibration. Structural studies confirm allele-specific peptide binding, with H2-Kb accommodating specific anchors in its closed-end groove.

Other names

H-2KbH2-K^bH-2K^b