Cloning of a partial cDNA for rat interleukin-12 (IL-12) and analysis of IL-12 expression in vivo.
Experimental models of autoimmunity in the rat may feature selective activation of either the Th1 or Th2 subset of helper T cells. Interleukin-12 (IL-12) is a key cytokine in the development of Th1 responses. In order to study IL-12 in the rat we used polymerase chain reaction (PCR) primers based on murine IL-12 to amplify a partial cDNA from rat tissue. The product was cloned and sequenced: it shows 94% nucleotide identity with the murine gene and 94% identity of predicted amino acid sequence. Primers based on the rat IL-12 sequence were used to analyse IL-12 expression in vivo using semi-quantitative PCR. We studied RNA from lymphoid tissues of two rat strains which differ in their response to mercuric chloride (HgCl2): Brown Norway (BN) rats develop autoimmunity with a predominant Th2 response; Lewis rats are resistant. Interleukin-12 expression was higher in Lewis than BN, and higher in spleen than lymph node. After HgCl2, IL-12 expression increased in BN towards the time when the autoimmune response autoregulates. Variation in baseline levels of IL-12 expression may account for the Th2 predisposition of BN rats compared to Lewis rats; IL-12 may play a role in the autoregulation of the Th2 response induced by HgCl2.
Mathieson
P W
PW
Academic Renal Unit, University of Bristol, Southmead Hospital, UK.
Gillespie
K M
KM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification*; D005786:Gene Expression Regulation / Q000187:drug effects; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification*; D008198:Lymph Nodes / Q000378:metabolism; D008627:Mercuric Chloride / Q000494:pharmacology; D008969:Molecular Sequence Data; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D013154:Spleen / Q000378:metabolism
D018076:DNA, Complementary; D018664:Interleukin-12; D008627:Mercuric Chloride