In DA rats, a single intradermal injection of pristane induces a chronic relapsing polyarthritis that can remain active for at least 200 days 18. production and the induction of lupus in mice 39, 40, 41. In DA rats, a single intradermal injection of pristane induces a chronic relapsing polyarthritis that can remain active for at least 200 days 18. The disease onset is usually early, highly synchronized between animals, and accompanied by elevated levels of IL\6, rheumatoid factor, and a strong acute phase response 15, 18, 42, 43. The induction of arthritis does not appear to be dependent on B cells or the production of antibodies, since adoptive transfer of CD4 T?cells from rats injected I-191 with pristane induces a disease in na?ve rats that closely mimics the manifestations in PIA 14, 18, 23, 44. Similar to RA, PIA is usually associated with multiple discrete loci in the MHC 15, 44 of which two have been mapped at high resolution; a 33\kb locus in the MHCIII\region ((contains 12 genes of which (are located within the QTL borders (Fig. ?(Fig.1A)1A) 12. We have previously shown that controls pathogenicity and growth of T?cells after pristane administration. (A) Physical map of the rat MHC\II region. Asterisked genes are located within the flanking borders of (value for cumulative incidence. (F) Rabbit polyclonal to AREB6 Expression of Ki67 in CD4+ (upper row) and CD8+ (lower row) activated/memory T?cells (CD90\ CD45RClo Foxp3\) in pristane dLNs at indicated time\points after disease induction. Counter I-191 plots show gating strategy and adjacent histograms representative examples of Ki67 expression in DA (black) and DA.1HR10 (shaded); = 5 per group. ACF: *donor into MHCII syngeneic recipient (here referred to as individual transfer; = 6 rats/ group; *= 5 rats/group; *= 9C10 per group. (B) Cytokine levels after in\vitro stimulation of dLN cells from DA and DA.1HR10 with anti\CD3/CD28. Cells were harvested 8 days after pristane administration. (C) Frequencies of IFN\+ (Th1) and IL\17+ (Th17) cells among non\RTE (CD90\) CD4+ T?cells. Dot plots show DA (upper row) and DA.1HR10 (lower row). Data are summarized in adjacent line chart. = I-191 5 rats/group. (D) Total number of CD90\ Th1 and Th17 cells in dLNs. AU = arbitrary models. (ACD) * 0.05; ** 0.01; *** 0.001 (by MannCWhitney). Results shown are representative I-191 of two to three independent experiments (A and B). Data shown in (C and D) are pooled from five impartial experiments. Error bars represent SEM (A, C, and D); vertical line represents mean (B). Flow cytometric analyses of CD4 T?cells showed that IFN\ producing Th1 cells increased by approximately twofold between day 3 and day 5 in DA and DA.1FR61 rats (Fig. ?(Fig.4C).4C). By contrast, the frequency of Th1 cells in DA.1HR10 and DA.1UR10 was only marginally increased during the first 5 days of PIA. Further, the total number of Th1 cells was significantly increased in dLNs from DA and DA.1FR61 compared to DA.1HR10 and DA.1UR10 on day 5 and 8 after immunization. (Fig. ?(Fig.4D).4D). Unlike unstimulated cells (Fig. ?(Fig.4A)4A) and cells stimulated with anti\CD3/CD28 (Fig. ?(Fig.4B),4B), PMA/ionomycin stimulation did not reveal any significant differences in IL\17 expression between the strains (data shown for total numbers of Th17 cells in Fig. ?Fig.44D). Taken together, these data show that after pristane administration T?cells differentiate predominantly into Th1 lineage in rats with arthritis susceptible MHCII alleles. Pristane\induced arthritis is dependent on IFN\ for T\cell priming and IL\17 for disease perpetuation A significant growth of Th1 cells was observed in strains with an early\onset PIA. To probe whether IFN\ I-191 is critical for the induction of arthritis, we treated rats with anti\IFN\ and anti\IL\17 neutralizing antibodies at day 2, 4, and 6 after pristane administration. All rats, regardless of MHCII haplotype, that were treated with anti\IFN\ Abs developed significantly milder disease compared to non\treated control rats (Fig. ?(Fig.5A),5A), whereas no effect was observed when treating with anti\IL\17 Abs (Fig. ?(Fig.5B).5B). In addition, the onset of PIA was delayed by up to 4 days in rats treated with anti\IFN\ Abs (Fig. ?(Fig.5C),5C), suggesting that T\cell priming in PIA is IFN\\dependent also in strains associated with a Th17 biased immune response, such as DA.1HR10. Open in a separate window Physique 5 Pristane\induced arthritis is dependent on IFN\ for T\cell priming. (A\B) Antibodies to INF\ (DB\1) (A) and.