MOLECULAR-CLONING AND EXPRESSION OF A FUNGAL IMMUNOMODULATORY PROTEIN, FIP-FVE, FROM FLAMMULINA VELUTIPES

FIP-fve, a fungal immunomodulatory protein, was isolated from the frui ting bodies of the edible mushroom, Flammulina velutipes. FIP-fve was shown to stimulate blast-forming activity of human peripheral blood ly mphocytes and gene expression of interleukin-2, interferon-gamma and t umor necrosis factor-alpha. Repeated adminstration of FIP-fve to mice inhibits the Arthur and systemic anaphylaxis reactions. FIP-fve cDNA w as cloned and sequenced, and the amino acid sequence of FIP-fve deduce d from the nucleotide sequence is identical to that previously determi ned by protein sequencing. FIP-fve cDNA was amplified by polymerase ch ain reaction, ligated into the expression vector, pGEX-2T, and express ed in Escherichia coli as a fusion protein of glutathione S-transferas e (GST) and FIP-fve. The GST-FIP-fve fusion protein was soluble, and t he yield of recombinant FIP-fve was about 5 mg/L of induced culture. T he recombinant FIP-fve was obtained by cleaving the GST-FIP-fve fusion protein with thrombin and purifing to homogeneity. The recombinant FI P-fve had about 50% of the immunomodulatory activity of the native FIP -fve.