Interleukin-4 gene expression in mercury-induced autoimmunity.
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.
Gillespie
K M
KM
Department of Medicine, University of Cambridge, UK.
Qasim
F J
FJ
Tibbatts
L M
LM
Thiru
S
S
Oliveira
D B
DB
Mathieson
P W
PW
D000818:Animals; D001327:Autoimmune Diseases / Q000139:chemically induced / Q000276:immunology* / Q000473:pathology; D001483:Base Sequence; D002432:Cecum / Q000276:immunology / Q000473:pathology; D015847:Interleukin-4 / Q000096:biosynthesis* / Q000235:genetics; D008627:Mercuric Chloride; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D051381:Rats; D011914:Rats, Inbred BN; D013154:Spleen / Q000276:immunology; D015854:Up-Regulation / Q000187:drug effects; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000139:chemically induced / Q000276:immunology / Q000473:pathology
D015847:Interleukin-4; D008627:Mercuric Chloride