Gillespie K M, Qasim F J, Tibbatts L M, Thiru S, Oliveira D B, Mathieson P W
Department of Medicine, University of Cambridge, UK.
Scand J Immunol. 1995 Mar;41(3):268-72. doi: 10.1111/j.1365-3083.1995.tb03563.x.
Mercuric chloride (HgCl2) induces autoimmunity in Brown Norway (BN) rats, with necrotizing vasculitis in the gut. Circumstantial evidence implicates the Th2 subset of CD4+ T lymphocytes, which produces IL-4. We developed a quantitative polymerase chain reaction (PCR) technique to quantify IL-4 gene expression. A phagemid containing rat IL-4 cDNA was modified to act as the template for a synthetic RNA construct; a known amount of synthetic RNA was added to total RNA from spleen and caecum of BN rats at various times after HgCl2, followed by reverse transcriptase PCR. IL-4 gene expression increased markedly in spleen and caecum after HgCl2. Splenic levels peaked by 10 days at approximately five-times baseline, then returned towards normal as the autoimmune response was spontaneously regulated. Caecal IL-4 expression peaked at 48 h, at which time we observed a previously unreported early phase of tissue injury, with necrotizing vasculitis qualitatively similar to that reported previously in the later phases of the model. These data support a key role for IL-4 in this experimental model of autoimmunity. The quantitative PCR technique can be modified for analysis of other cytokines, allowing further investigation of the role of T cell subsets in this model.
