GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AMPLIFICATION OF INTERLEUKIN-1-BETA AND TUMOR-NECROSIS-FACTOR-ALPHA PRODUCTION IN THP-1 HUMAN MONOCYTIC CELLS STIMULATED WITH LIPOPOLYSACCHARIDE OF ORAL MICROORGANISMS

Cytokines, including granulocyte-macrophage colony-stimulating factor (GM-CSF), are used to assist in bone marrow recovery during cancer che motherapy. Interleukin-1 beta (IL-1 beta) and tumor necrosis factor al pha (TNF-alpha) play important roles in inflammatory processes, includ ing exacerbation of periodontal diseases, one of the most common compl ications in patients who undergo this therapy. A human monocyte cell l ine (THP-1) was utilized to investigate IL-1 beta and TNF-alpha produc tion following GM-CSF supplementation with lipopolysaccharide (LPS) fr om two oral microorganisms, Porphyromonas gingivalis and Fusobacterium nucleatum, LPS of P. gingivalis or F. nucleatum was prepared by a phe nol-water extraction method and characterized by sodium dodecyl sulfat e-polyacrylamide gel electrophoresis and determination of total protei n and endotoxin contents. Resting THP-1 cells were treated with LPS of P. gingivalis or F. nucleatum and/or GM-CSF (50 IU/ml) by using diffe rent concentrations for various time periods. Production of IL-1 beta and TNF-alpha in THP-1 cells was measured by solid-phase enzyme-linked immunosorbent assay. Reverse transcription (RT)-PCR was used to evalu ate the gene expression of resting and treated THP-1 cells. IL-1 beta was not detected in untreated THP-1 cells. IL-1 beta production was, h owever, stimulated sharply at 4 h, GM-CSF amplified IL-1 beta producti on in THP-I cells treated with LPS from both oral anaerobes, No IL-1 b eta-specific mRNA transcript was detected in untreated THP-1 cells. Ho wever, IL-1 beta mRNA was detected by RT-PCR 2 h after stimulation of THP-1 cells with LPS from both organisms. GM-CSF did not shorten the I L-1 beta transcriptional activation time. GM-CSF plus F. nucleatum or P. gingivalis LPS activated THP-1 cells to produce a 1.6-fold increase in TNF-alpha production at 4 h over LPS stimulation alone. These inve stigations with the in vitro THP-I model indicate that there may be an increase in the cellular immune response to oral endotoxin following GM-CSF therapy, as evidenced by production of the tissue-reactive cyto kines IL-1 beta and TNF-alpha.