CONTAMINATION WITH MYCOPLASMA SPP INDUCES INTERLEUKIN-13 EXPRESSION BY HUMAN SKIN FIBROBLASTS IN CULTURE

The mycoplasmas comprise a discrete group of microorganisms that are k nown to exert a range of effects upon cells derived from the immune sy stem. Some of these interactions turn out to be immunomodulatory, such as polyclonal stimulation of T and B cells or enhancement of the cyto lytic potential of macrophages, NK cells and T lymphocytes. Immunologi cally committed cells, when infected with mycoplasmas, can also increa se the production of cytokines (IL-1, IL-2, IL-4 and IL-6); interferon (IFN)gamma, tumor necrosis factor-alpha (TNF-alpha) and colony-stimul ating factors (particularly GM-CSF). Moreover. mycoplasmas are potent inductors of cytokine secretion by fibroblasts in culture. Since growt h factors are determinants for the activation and proliferation of imm unocompetent cells in vitro, we decided to investigate if these effect s are concordant with the finding of mycoplasma contamination. In orde r to address this question, we compared the pattern of lymphokine secr etion by normal-derived human fibroblasts in culture with and without Mycoplasma spp. contamination. We found those human fibroblasts that h ave been contaminated with mycoplasma show production of IL-13 at the transcriptional level. This effect coincides with discrete morphologic al changes as compared to uncontaminated human fibroblasts. This is th e first report to acknowledge that mycoplasma contamination can induce mRNA expression for IL-13 in cultured human fibroblasts.