HUMAN GLIOBLASTOMA CELLS PRODUCE 77 AMINO-ACID INTERLEUKIN-8 (IL-877)

The production of interleukin 8 (IL-8), a neutrophil chemotactic facto r, and its amino acid sequence were examined in glioblastoma cell line s in vitro. Neutrophil chemotactic activity was demonstrated in 9 cond itioned media of 15 human glioblastoma cell lines. Tumor necrosis fact or (TNF)-alpha stimulated secretion of the activity in 7 lines and ind uced secretion in 4 other lines. ELISA quantification disclosed that t he conditioned media contained interleukin 8 (IL-8) in an amount equiv alent to the chemotactic activity. The IL-8 secretion increased with t he stimulation by TNF-alpha. Northern blot analysis and the RT-PCR met hod confirmed expression of mRNA in the glioblastoma cells and its aug mentation by TNF-alpha and/or IL-beta. Reversed-phase HPLC following i on-exchange chromatography revealed that the chemotactic activity was a single peptide, which was determined to be IL-8 by the retention tim e and ELISA. Furthermore, amino acid analysis disclosed that a major p art of the glioblastoma-cell derived IL-8 peptide was 77 amino acid IL -8 (IL-877; with the N-terminal sequence AVLPRSAKELRCQCI-).