Mercury exposure as a model for deviation of cytokine responses in experimental Lyme arthritis: HgCl2 treatment decreases T helper cell type 1-like responses and arthritis severity but delays eradication of Borrelia burgdorferi in C3H/HeN mice
2007 (English)In: Clinical and Experimental Immunology, ISSN 0009-9104, E-ISSN 1365-2249, Vol. 150, no 1, 189-197 p.Article in journal (Refereed) Published
Lyme borreliosis is a complex infection, where some individuals develop so-called ‘chronic borreliosis’. The pathogenetic mechanisms are unknown, but the type of immune response is probably important for healing. A strong T helper cell type 1 (Th1)-like response has been suggested as crucial for eradication of Borrelia and for avoiding development of chronic disease. Many studies aimed at altering the Th1/Th2 balance in Lyme arthritis employed mice deficient in cytokine genes, but the outcome has not been clear-cut, due possibly to the high redundancy of cytokines. This study aimed at studying the importance of the Th1/Th2 balance in murine Borrelia arthritis by using the Th2-deviating effect of subtoxic doses of inorganic mercury. Ninety-eight C3H/HeN mice were divided into four groups: Borrelia-infected (Bb), Borrelia-infected exposed to HgCl2 (BbHg), controls exposed to HgCl2 alone and normal controls. Mice were killed on days 3, 16, 44 and 65 post-Borrelia inoculation. Arthritis severity was evaluated by histology, spirochaetal load determined by Borrelia culture, IgG2a- and IgE-levels analysed by enzyme-linked immunosorbemt assay (ELISA) and cytokine-secreting cells detected by enzyme-linked immunospot (ELISPOT). BbHg mice showed less severe histological arthritis, but delayed eradication of spirochaetes compared to Bb mice, associated with increased levels of IgE (Th2-induced) and decreased levels of IgG2a (Th1-induced), consistent with a Th2-deviation. Both the numbers of Th1 and Th2 cytokine-secreting cells were reduced in BbHg mice, possibly explained by the fact that numbers of cytokine-secreting cells do not correlate with cytokine concentration. In conclusion, this study supports the hypothesis that a Th1-like response is required for optimal eradication of Borrelia.
Place, publisher, year, edition, pages
2007. Vol. 150, no 1, 189-197 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-41251DOI: 10.1111/j.1365-2249.2007.03474.xLocal ID: 55401OAI: oai:DiVA.org:liu-41251DiVA: diva2:262102