Published online Nov 6, 2014. doi: 10.5315/wjh.v3.i4.128
Revised: February 18, 2014
Accepted: February 20, 2014
Published online: November 6, 2014
Granulysin is a cytotoxic granular protein that was identified from human T cells by using the gene subtraction method in 1987. Based on its amino acid homology, granulysin belongs to the saposin-like protein family. The bioactive 9-kDa form of granulysin is processed from the 15-kDa pro-product in the cytoplasmic granules. It is expressed in CD8-positive αβT cells 5 d after mitogenic stimulation and constitutively in natural killer (NK) cells and γδT cells, although regulation of its expression has not yet been precisely determined. The 9-kDa granulysin form has anti-microbial activity against microorganisms such as bacteria, fungi, mycobacteria and parasites, as well as tumoricidal activity against some tumors at 1-10 μmol/L concentrations. Granulysin is secreted in both Ca-dependent and -independent manners. In sera, only the 15-kDa form is detectable and is expected to be a biomarker for immune potency, acute viral infection, anti-tumor immune reaction, acute graft vs host disease, and NK cell associated neoplasm.
Core tip: Granulysin is a cytotoxic granular protein expressed in cytotoxic T cells, natural killer (NK) cells and γδT cells, and has anti-microbial activity against microorganisms such as bacteria, fungi, mycobacteria and parasites, as well as tumoricidal activity against some tumors. It is secreted constitutively and in a trigger-dependent manner. Clinically, serum granulysin is a unique biomarker for immune response, immune capacity and NK cell related neoplasms.