Cytokine production by SV40-transformed adherent synovial cells from rheumatoid arthritis patients

We examined the mRNA levels for various cytokines, including IL-1 alpha, IL-1 beta, TNF alpha, TGF-beta 1, GM-CSF, IL-6, IL-8, bFGF, PDGF-A, PDGF-B and IL-1ra, and IL-1 beta converting enzyme, and the protein levels of some of these cytokines in 19 SV40-transformed synovial cell clones. Among those tested, the mRNA levels for IL-6, bFGF and PDGF-A in rheumatoid arthritis (RA) cell clones were greater than those in non-RA cell clones. Moreover, except for one osteoarthritis (OA) cell clone, the mRNA levels for IL-8 in RA cell clones were also greater than those in non-RA cell clones. Although the protein levels were not always correlated with the mRNA levels, the exception being the same OA cell clone, the protein levels of cytokines, such as IL-1 alpha, IL-1 beta, IL-6 and IL-8, in RA cell clones were greater than those in non-RA cell clones. TNF-a was not detected in any cells tested at either the mRNA or the protein level. TNF-alpha upregulated the expression of GM-CSF mRNA in both RA cell clones and one OA cell clone, but not in the other OA cell clone or the normal cell clone. Taken together, these SV-40 transformed synovial cell clones retained many of the original characteristics in terms of cytokine production.