Keyhole limpet hemocyanin-derived peptides presented on MHC (KLH-MHC)

Keyhole limpet hemocyanin (KLH) is a highly immunogenic, high-molecular-weight metalloprotein derived from the hemolymph of the giant keyhole limpet, Megathura crenulata [1][4]. In therapeutic and diagnostic applications, KLH is internalized by professional antigen-presenting cells (APCs), such as dendritic cells, and proteolytically processed into peptide fragments [2]. These KLH-derived peptides are subsequently loaded onto Major Histocompatibility Complex (MHC) molecules, primarily Class II, and presented on the cell surface for recognition by T-cell receptors (TCRs) [2][4]. This interaction triggers a robust cellular immune response, characterized by the activation of CD4+ T-helper cells and the secretion of pro-inflammatory cytokines [2]. Because of its potent ability to stimulate the immune system, KLH is widely used as a carrier protein to enhance the immunogenicity of haptens and weak tumor antigens in conjugate vaccines [1][3]. Additionally, the presentation of KLH-MHC complexes is utilized as a clinical tool to assess T-cell-dependent immune function and as a non-specific immunotherapy for superficial bladder cancer [3][4].

Other names

KLH-derived peptidesKLH-MHC complexMegathura crenulata hemocyanin peptidesKLH antigenKeyhole limpet hemocyanin

Presentation of KLH-derived peptides on MHC molecules to T-cell receptors, leading to the activation of CD4+ helper T cells and the subsequent release of cytokines that enhance B-cell and CD8+ T-cell responses.