Spontaneous cytokine gene expression in normal guinea pig blood and tissues

The authors report, for the first time, the cloning, characterization and s equencing of guinea pig cDNAs for interleukin (IL)-2, IL-10, IL-12p40, and transforming growth factor beta (TGF-beta). Partial cDNAs for two additiona l cytokines, IL-1 alpha and TNF-alpha, whose sequences are present in the G enEMBL database, were also cloned. The IL-10 clone is a full-length cDNA, w hile the remaining clones are partial cDNAs. The guinea pig cDNA sequences have high identity with their mouse and human counterparts. Northern blot a nalysis revealed that the guinea pig transcripts range in size from 1.0 kb to 2.2 kb. The constitutive expression of cytokines in two strains of guine a pig (C4D, Albany) that differ in susceptibility to infection with Trepone ma pallidum was examined. Since susceptibility to T. pallidum is also age d ependent, both neonates and adults were examined. Spontaneous cytokine expr ession was examined in peripheral blood, skin, spleen, lymph node, brain, a nd peritoneal cells. In skin, lymph node, and peripheral blood, very low le vels of IL-1 alpha, IL-12p40, tumour necrosis factor alpha (TNF-alpha), and TGF-beta and moderate levels of IL-2 and IL-10 were observed. Cytokine gen e expression was not observed in spleen and brain. Peritoneal cells express ed;only TGF-beta. Age- and strain-associated differences were not observed, except for IL-12p40, which was elevated in guinea pigs resistant to T. pal lidum infection (C4D neonates, Albany adults). (C) 1998 Academic Press.