Increased expression and secretion of interleukin‐6 in human parvovirus B19 non‐structural protein (NS1) transfected COS‐7 epithelial cells

Summary Human parvovirus B19 (B19) has been associated with a variety of autoimmune diseases, including rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We have demonstrated previously that B19 non‐structural protein (NS1) induced apoptosis through the mitochondria cell death pathway in COS‐7 epithelial cells and that B19 NS1 may play a role in the pathogenesis of autoimmune diseases. In order to examine the expression profiles of cytokines and chemokines in B19 NS1 transfected COS‐7 cells, we constructed the NS1 gene in the pEGFP‐C1 vector named enhanced green fluorescence protein gene (EGFP)‐NS1. COS‐7 cells were transfected with EGFP or EGFP‐NS1 plasmid. The expression profiles of cytokines and chemokines, including interleukin (IL)‐1β, IL‐5, IL‐6, IL‐8, IL‐10, tumour necrosis factor (TNF)‐α, transforming growth factor (TGF)‐β, granulocyte–macrophage colony‐stimulating factor (GM‐CSF), growth‐related oncogene α (GROα), interferon gamma‐inducible protein (IP)‐10, stromal cell derived factor (SDF)‐1, macrophage inflammatory protein (MIP)‐1β, monocyte chemoattractant protein (MCP)‐1, regulated upon activation normal T cell expressed and secreted (RANTES), Fractalkine, CX3CR1, CCR2, CCR5 and CCR11 were examined in COS‐7 cells, EGFP and EGFP‐NS1 transfected cells using enzyme‐linked immunosorbent assay (ELISA) or reverse transcription–polymerase chain reaction (RT–PCR). Increased expression and levels of IL‐6 were found in EGFP‐NS1 transfected cells using RT–PCR and ELISA. There were no significant increases in the expression of IL‐1β, IL‐8, IP‐10, SDF‐1, RANTES, Fractalkine, CX3CR‐1, CCR2, CCR5, CCR11, TNF‐α, GM‐CSF and TGF‐β using RT–PCR. There were no significantly increased levels of IL‐5, IL‐10, TNF‐α, TGF‐β, GROα, MIP‐1β and MCP‐1 found by ELISA in this study. Our results show that increased expression and secretion of IL‐6 in B19 NS1 transfected epithelial cells may play a role in the pathogenesis of autoimmune diseases.